Discussion:
To Megger or not to Megger
(too old to reply)
Keith Cronin
2009-04-27 21:36:35 UTC
Permalink
Hi

I was wondering, by a show of hands, how many of you megger every project?

Do you have a cut off- like if it is "x" sized system, you will or decide to opt out of performing this task?




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Max Balchowsky
2009-04-27 23:16:11 UTC
Permalink
I haven't used a meggar since I stopped designing traffic signal systems. No ill affects so far ( 20 years now )

Max Balchowsky
SEE Systems




________________________________
From: Keith Cronin <electrichi01 at yahoo.com>
To: RE-Wrenches <re-wrenches at lists.re-wrenches.org>
Sent: Monday, April 27, 2009 2:36:35 PM
Subject: [RE-wrenches] To Megger or not to Megger


Hi

I was wondering, by a show of hands, how many of you megger every project?

Do you have a cut off- like if it is "x" sized system, you will or decide to opt out of performing this task?
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Matt Lafferty
2009-04-28 03:08:28 UTC
Permalink
Hi Keith,

Both hands up here. From day 1 in PV.

Every single field-installed current carrying conductor to the point of
termination. AC & DC. BEFORE energizing them! One megger lead on the
conductor, the other on the raceway or ground-wire. Megger @ 1kV. Must be
greater than 250 Megohms to pass. Record the values on your commissioning
sheet.

I only meggered the actual arrays on projects where it was a requirement and
I only did that following specific procedures provided by the module
manufacturer. No procedure from the mfr = No array megger.

I believe it's a critical thing to do as part of the commissioning. But then
again, I don't like ground faults or fires.

I'll never forget a couple of head scratchers that the megger found.... One
was a perfectly fine, 6' long piece of Orange #12 XHHW-2 that would only
pull 40 Megohms installed in EMT. Pulled it out and replaced it. Inspected
it for any visible flaws. None found. Not a scratch or scuff. Used it as a
training tool for my guys. Hung it on the wall over my desk as a handy
reminder. If anybody wants a picture...

The other was interesting, too. The very first PV system I ever installed.
Was shooting the DC circuits from the inverter all the way to the connector
on the output jumper cables at the modules. Megger showed dead short on one
wire. Fluke 79 on ohms showed clear. Hit it with the megger again. Dead
short. I'm known for being anal about conduit and wire installation, so this
was quite unexpected, not to mention a little embarrassing. This happened to
be a Solarex Millennia Integra system with an Omnion inverter and the array
happened to be scattered all over this roof. For those of you who who have
dealt with that situation, you'll understand what a cluster-*$#! that is...
Especially being my very first PV system and all... I wasn't anywhere near
confident that I had a clue by that point. All ready to see my first install
fire up and this happens.

It was my first install and I had 3 people getting paid prevailing wages to
learn... I was learning too, but I wasn't making anywhere near prevailing
wages, let me tell ya. Well, it was early January, late in the day and foggy
as foggy gets, but we went back onto the roof anyway. Yeah... Overtime for
everybody but me. We opened up the condulets and J-boxes for inspection.
Pulled all the wires up out of the J-boxes. Pulled the endcaps and ground
clips off (unique components of the Integra product). Couldn't find anything
suspicious. Shot it with the megger again, and it was all clear. But no sign
of anything that could have been shorted. We put everything back together
and shot it again. Dead short! Aiyeeeee!

Call it a day. Go home. I couldn't get back to that site until about the
same time the next day. Foggy again. Only took 1 helper with me this time.
We completely repeated the entire exercise, with exactly the same results.
By now, I was pretty sure this solar stuff wasn't my calling. I've always
been regarded as a gifted trouble-shooter and all I could say at this point
was that I didn't know _____! All signs pointed to it being associated with
one of the J-boxes or the endcaps or the ground clips, but there was NOT a
thing we could see. Oh, well. I would have to come back another day. When I
went back, I took the same helper and made sure I had all day if necessary
to fix the problem. No matter what it turned out to be. We planned to take
it apart 1 piece at a time and re-shoot it with the megger after each step.
I left my helper on the ground with the megger while I took it apart on the
roof, 1 screw at a time. Again.

Well, lo and behold, he hollers up that "It's clear" when I pulled the cover
off one of the 2-gang bell boxes. Hadn't moved a wire. Just took the cover
off. Let me tell ya, I stuck my nose and four eyes in that box real close,
but didn't touch any wires. The box was a tight fit with those big,
sealant-filled blue wire nuts that came with the Solarex Kit, but I still
couldn't see anything wierd.

"Shoot it again."

"All clear, boss."

I put the cover back on and installed all the screws. "Shoot it again."

"Dead short." We had a talk later about shouting things like "Dead short" on
the jobsite, but I won't get into all that right now.

I took out one of the cover screws. "Shoot it again." Same answer from the
ground.

I took out a second screw. "Shoot it again." This time the reply was
different. I took out the third screw and we repeated the process. Still
clear. And the fourth. Still clear. WTF? I lifted the cover for what seemed
like the hundredth time. I studied the nested wires, all neatly and
systematically put into what I had thought would be their final resting
place... Days before and time and time again at this point.

I began gently lifting the wires out so they all stood up like dandelions in
a spring lawn. I inspected them for the nth time. Looking for a stray strand
outside its protective hat. Nope. Overtightened wire nut with the spring or
a conductor coming out the tip? Nope. But what's this little, nearly
imperceptible dent in the side of this wire nut? As I looked closer, I could
see that it was round, flat bottomed and about the same diameter as a 6-32
screw. Hmmmm. I rolled the wires back into their resting position. Uh, huh.
This particular wire nut's natural home was directly under the cover screw
which had cleared the fault when removed and the dent lined up perfectly.
The screw could just barely be long enough to pierce the plastic and contact
the wire-spring.

I replaced the wire nut, repositioned the conductors to make sure we
wouldn't have a repeat, and buttoned up the J-box. I put the wirenut in my
pocket for later reference. One more megger shot proved the system to be all
clear. We could now energize the DC and do our Voc & Isc testing prior to
startup. Thank goodness the sun was shining. I wasn't happy about this whole
ordeal, but it was a good thing we caught it with the megger before we put
the power to it.

That wire nut became the first exhibit in what became my collection of
training materials for the "what can go wrong and why we do these
procedures" trainings. Verification that cover and mounting screws cannot
come in contact with energized equipment was officially put in the
checklist. All cover & mounting screws in all types of enclosures. There
would be no exceptions. There would be no excuses. I actually had to write
one guy up for a violation of this at one point. Good thing we caught that
one with the megger before putting the power to it.

I would posit that at least one of the recent PV fires would absolutely have
been prevented if the installer followed the procedure described above. Too
bad most don't. Kudos to those of you who do. It's only a matter of time
until more and more of these AVOIDABLE problems surface.

If you don't have a megger, get one. If you have one, use it! The Fluke 1520
is a nice unit. I recommend it over analog models. I cut my teeth with
analog gear, but really like my 1520. A lot! Rugged instrument that gives
you an actual number to write on your commissioning sheet. In addition to
Megohms, it also does VAC, Lo Ohms, Continuity, has a display backlight,
Lock and Zero functions and my favorite.... Battery Check! Reads out an
actual % value for your battery condition. Nice! Uses 4 "C" cells.

I hope more hands go up on this topic. Thanks for asking, Keith.

Peace and Palm Trees everybody,

Matt Lafferty

_____

From: re-wrenches-bounces at lists.re-wrenches.org
[mailto:re-wrenches-bounces at lists.re-wrenches.org] On Behalf Of Keith Cronin
Sent: Monday, April 27, 2009 2:37 PM
To: RE-Wrenches
Subject: [RE-wrenches] To Megger or not to Megger


Hi

I was wondering, by a show of hands, how many of you megger every project?

Do you have a cut off- like if it is "x" sized system, you will or decide to
opt out of performing this task?


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David Katz
2009-04-28 04:49:55 UTC
Permalink
Wrenches,
Here is a really scary link. the guy is selling a book for $50 that
shows you how you can build your own PV module for $125.
http://www.power4home.com/index.php?hop=roeib
Cheers

David Katz


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Wind-sun.com
2009-04-28 05:17:56 UTC
Permalink
Microsoft Outlook Signaturepower4home and earth4energy (same outfit I think) have been on our public scam list for over a year now.

..................................................................................................
Northern Arizona Wind & Sun - Electricity From The Sun Since 1979
Solar Discussion Forum: http://www.wind-sun.com/ForumVB/
..................................................................................................
----- Original Message -----
From: David Katz
To: RE-wrenches
Sent: Monday, April 27, 2009 9:49 PM
Subject: [RE-wrenches] Cheap solar


Wrenches,
Here is a really scary link. the guy is selling a book for $50 that shows you how you can build your own PV module for $125.
http://www.power4home.com/index.php?hop=roeib
Cheers


David Katz





------------------------------------------------------------------------------


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Roy Butler
2009-04-28 13:47:44 UTC
Permalink
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Ken Schaal
2009-04-28 15:11:04 UTC
Permalink
You can kill all those pop-ups manually in Windows by using the Task Manager to end the process:
1) Press Ctrl and Alt and Delete at the same time
This brings up Task Manager

2) Go to the "Processes" tab

Click on the Mem Usage column to bring those items that consume the most system resources up to the top or bottom.
Generally your web browser (like iexplor.exe for Windows Explorer) will rise to the top two or three items consuming memory resources for less scrolling around. Or maybe its Mozilla, whichever is the browser you are using.

3) Click on that process to highlight

4) lower right hand corner press "End Process"
Click Yes on the warning that ending processes can make the computer unstable.

And voila, all those popups are GONE!


----- Original Message -----

I especially like the popups that won't let you leave the site.....
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David Palumbo
2009-08-10 17:11:33 UTC
Permalink
Hi Ken,



Good talking with you again. We could use 9' x 9' of the reinforced
polyethelene vapor barrier. It would not hurt for us to have double, so you
could sell us 10' by 20' and fold it up for UPS if you can do that.



You could invoice me, or I could give you a credit card over the phone. We
would like the material as soon as you can get it out.



Dave



David Palumbo, President

Independent Power LLC

462 Solar Way Drive

Hyde Park, VT 05655

NABCEP Certified

www.independentpowerllc.com





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David Palumbo
2009-08-10 17:11:33 UTC
Permalink
Hi Ken,



Good talking with you again. We could use 9' x 9' of the reinforced
polyethelene vapor barrier. It would not hurt for us to have double, so you
could sell us 10' by 20' and fold it up for UPS if you can do that.



You could invoice me, or I could give you a credit card over the phone. We
would like the material as soon as you can get it out.



Dave



David Palumbo, President

Independent Power LLC

462 Solar Way Drive

Hyde Park, VT 05655

NABCEP Certified

www.independentpowerllc.com





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Ken Schaal
2009-04-28 15:11:04 UTC
Permalink
You can kill all those pop-ups manually in Windows by using the Task Manager to end the process:
1) Press Ctrl and Alt and Delete at the same time
This brings up Task Manager

2) Go to the "Processes" tab

Click on the Mem Usage column to bring those items that consume the most system resources up to the top or bottom.
Generally your web browser (like iexplor.exe for Windows Explorer) will rise to the top two or three items consuming memory resources for less scrolling around. Or maybe its Mozilla, whichever is the browser you are using.

3) Click on that process to highlight

4) lower right hand corner press "End Process"
Click Yes on the warning that ending processes can make the computer unstable.

And voila, all those popups are GONE!


----- Original Message -----

I especially like the popups that won't let you leave the site.....
-------------- next part --------------
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Wind-sun.com
2009-04-28 05:17:56 UTC
Permalink
Microsoft Outlook Signaturepower4home and earth4energy (same outfit I think) have been on our public scam list for over a year now.

..................................................................................................
Northern Arizona Wind & Sun - Electricity From The Sun Since 1979
Solar Discussion Forum: http://www.wind-sun.com/ForumVB/
..................................................................................................
----- Original Message -----
From: David Katz
To: RE-wrenches
Sent: Monday, April 27, 2009 9:49 PM
Subject: [RE-wrenches] Cheap solar


Wrenches,
Here is a really scary link. the guy is selling a book for $50 that shows you how you can build your own PV module for $125.
http://www.power4home.com/index.php?hop=roeib
Cheers


David Katz





------------------------------------------------------------------------------


_______________________________________________
List sponsored by Home Power magazine

List Address: RE-wrenches at lists.re-wrenches.org

Options & settings:
http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org

List-Archive: http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org

List rules & etiquette:
www.re-wrenches.org/etiquette.htm

Check out participant bios:
www.members.re-wrenches.org

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Roy Butler
2009-04-28 13:47:44 UTC
Permalink
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robert ellison
2009-04-28 10:24:25 UTC
Permalink
Just went to check the Fluke 1520 price. Looks like it is discontinued.
They do have a couple suggested replacements.

Just for reference,
Bob

On Mon, Apr 27, 2009 at 11:08 PM, Matt Lafferty <gilligan06 at gmail.com>wrote:

> Hi Keith,
>
> Both hands up here. From day 1 in PV.
>
> Every single field-installed current carrying conductor to the point of
> termination. AC & DC. BEFORE energizing them! One megger lead on the
> conductor, the other on the raceway or ground-wire. Megger @ 1kV. Must be
> greater than 250 Megohms to pass. Record the values on your commissioning
> sheet.
>
> I only meggered the actual arrays on projects where it was a requirement
> and I only did that following specific procedures provided by the module
> manufacturer. No procedure from the mfr = No array megger.
>
> I believe it's a critical thing to do as part of the commissioning. But
> then again, I don't like ground faults or fires.
>
> I'll never forget a couple of head scratchers that the megger found.... One
> was a perfectly fine, 6' long piece of Orange #12 XHHW-2 that would only
> pull 40 Megohms installed in EMT. Pulled it out and replaced it. Inspected
> it for any visible flaws. None found. Not a scratch or scuff. Used it as a
> training tool for my guys. Hung it on the wall over my desk as a handy
> reminder. If anybody wants a picture...
>
> The other was interesting, too. The very first PV system I ever installed. Was
> shooting the DC circuits from the inverter all the way to the connector on
> the output jumper cables at the modules. Megger showed dead short on one
> wire. Fluke 79 on ohms showed clear. Hit it with the megger again. Dead
> short. I'm known for being anal about conduit and wire installation, so
> this was quite unexpected, not to mention a little embarrassing. This
> happened to be a Solarex Millennia Integra system with an Omnion inverter
> and the array happened to be scattered all over this roof. For those of you
> who who have dealt with that situation, you'll understand what a
> cluster-*$#! that is... Especially being my very first PV system and
> all... I wasn't anywhere near confident that I had a clue by that point. All
> ready to see my first install fire up and this happens.
>
> It was my first install and I had 3 people getting paid prevailing wages to
> learn... I was learning too, but I wasn't making anywhere near prevailing
> wages, let me tell ya. Well, it was early January, late in the day and
> foggy as foggy gets, but we went back onto the roof anyway. Yeah... Overtime
> for everybody but me. We opened up the condulets and J-boxes for
> inspection. Pulled all the wires up out of the J-boxes. Pulled the endcaps
> and ground clips off *(unique components of the Integra product)*.
> Couldn't find anything suspicious. Shot it with the megger again, and it was
> all clear. But no sign of anything that could have been shorted. We put
> everything back together and shot it again. Dead short! Aiyeeeee!
>
> Call it a day. Go home. I couldn't get back to that site until about the
> same time the next day. Foggy again. Only took 1 helper with me this time.
> We completely repeated the entire exercise, with exactly the same results.
> By now, I was pretty sure this solar stuff wasn't my calling. I've always
> been regarded as a gifted trouble-shooter and all I could say at this point
> was that I didn't know _____! All signs pointed to it being associated with
> one of the J-boxes or the endcaps or the ground clips, but there was NOT a
> thing we could see. Oh, well. I would have to come back another day. When
> I went back, I took the same helper and made sure I had all day if necessary
> to fix the problem. No matter what it turned out to be. We planned to
> take it apart 1 piece at a time and re-shoot it with the megger after each
> step. I left my helper on the ground with the megger while I took it apart
> on the roof, 1 screw at a time. Again.
>
> Well, lo and behold, he hollers up that "It's clear" when I pulled the
> cover off one of the 2-gang bell boxes. Hadn't moved a wire. Just took the
> cover off. Let me tell ya, I stuck my nose and four eyes in that box real
> close, but didn't touch any wires. The box was a tight fit with those big,
> sealant-filled blue wire nuts that came with the Solarex Kit, but I still
> couldn't see anything wierd.
>
> "Shoot it again."
>
> "All clear, boss."
>
> I put the cover back on and installed all the screws. "Shoot it again."
>
> "Dead short." We had a talk later about shouting things like "Dead short"
> on the jobsite, but I won't get into all that right now.
>
> I took out one of the cover screws. "Shoot it again." Same answer from the
> ground.
>
> I took out a second screw. "Shoot it again." This time the reply was
> different. I took out the third screw and we repeated the process. Still
> clear. And the fourth. Still clear. WTF? I lifted the cover for what seemed
> like the hundredth time. I studied the nested wires, all neatly and
> systematically put into what I had thought would be their final resting
> place... Days before and time and time again at this point.
>
> I began gently lifting the wires out so they all stood up like dandelions
> in a spring lawn. I inspected them for the nth time. Looking for a stray
> strand outside its protective hat. Nope. Overtightened wire nut with the
> spring or a conductor coming out the tip? Nope. But what's this little,
> nearly imperceptible dent in the side of this wire nut? As I looked closer,
> I could see that it was round, flat bottomed and about the same diameter as
> a 6-32 screw. Hmmmm. I rolled the wires back into their resting position.
> Uh, huh. This particular wire nut's natural home was directly under the
> cover screw which had cleared the fault when removed and the dent lined up
> perfectly. The screw could just barely be long enough to pierce the plastic
> and contact the wire-spring.
>
> I replaced the wire nut, repositioned the conductors to make sure we
> wouldn't have a repeat, and buttoned up the J-box. I put the wirenut in my
> pocket for later reference. One more megger shot proved the system to be all
> clear. We could now energize the DC and do our Voc & Isc testing prior to
> startup. Thank goodness the sun was shining. I wasn't happy about this whole
> ordeal, but it was a good thing we caught it with the megger before we put
> the power to it.
>
> That wire nut became the first exhibit in what became my collection of
> training materials for the "what can go wrong and why we do these
> procedures" trainings. Verification that cover and mounting screws cannot
> come in contact with energized equipment was officially put in the
> checklist. *All *cover & mounting screws in *all* types of enclosures.
> There would be no exceptions. There would be no excuses. I actually had to
> write one guy up for a violation of this at one point. Good thing we caught
> that one with the megger before putting the power to it.
>
> I would posit that at least one of the recent PV fires would *absolutely
> have been prevented* if the installer followed the procedure described
> above. Too bad most don't. Kudos to those of you who do. It's only a
> matter of time until more and more of these AVOIDABLE problems surface.
>
> If you don't have a megger, get one. If you have one, use it! The Fluke
> 1520 is a nice unit. I recommend it over analog models. I cut my teeth with
> analog gear, but really like my 1520. A lot! Rugged instrument that gives
> you an actual number to write on your commissioning sheet. In addition to
> Megohms, it also does VAC, Lo Ohms, Continuity, has a display backlight,
> Lock and Zero functions and my favorite.... Battery Check! Reads out an
> actual % value for your battery condition. Nice! Uses 4 "C" cells.
>
> I hope more hands go up on this topic. Thanks for asking, Keith.
>
> Peace and Palm Trees everybody,
>
> Matt Lafferty
>
> ------------------------------
> *From:* re-wrenches-bounces at lists.re-wrenches.org [mailto:
> re-wrenches-bounces at lists.re-wrenches.org] *On Behalf Of *Keith Cronin
> *Sent:* Monday, April 27, 2009 2:37 PM
> *To:* RE-Wrenches
> *Subject:* [RE-wrenches] To Megger or not to Megger
>
> Hi
>
> I was wondering, by a show of hands, how many of you megger every project?
>
> Do you have a cut off- like if it is "x" sized system, you will or decide
> to opt out of performing this task?
>
>
> _______________________________________________
> List sponsored by Home Power magazine
>
> List Address: RE-wrenches at lists.re-wrenches.org
>
> Options & settings:
> http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org
>
> List-Archive:
> http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org
>
> List rules & etiquette:
> www.re-wrenches.org/etiquette.htm
>
> Check out participant bios:
> www.members.re-wrenches.org
>
>
>
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David Palumbo
2009-04-28 12:33:16 UTC
Permalink
What are the options to the Fluke 1520? Also what are good sources for
purchasing these pricey meters?



Dave



From: re-wrenches-bounces at lists.re-wrenches.org
[mailto:re-wrenches-bounces at lists.re-wrenches.org] On Behalf Of robert
ellison
Sent: Tuesday, April 28, 2009 6:24 AM
To: RE-wrenches
Subject: Re: [RE-wrenches] To Megger or not to Megger



Just went to check the Fluke 1520 price. Looks like it is discontinued.

They do have a couple suggested replacements.



Just for reference,

Bob

On Mon, Apr 27, 2009 at 11:08 PM, Matt Lafferty <gilligan06 at gmail.com>
wrote:

Hi Keith,



Both hands up here. From day 1 in PV.



Every single field-installed current carrying conductor to the point of
termination. AC & DC. BEFORE energizing them! One megger lead on the
conductor, the other on the raceway or ground-wire. Megger @ 1kV. Must be
greater than 250 Megohms to pass. Record the values on your commissioning
sheet.



I only meggered the actual arrays on projects where it was a requirement and
I only did that following specific procedures provided by the module
manufacturer. No procedure from the mfr = No array megger.



I believe it's a critical thing to do as part of the commissioning. But then
again, I don't like ground faults or fires.



I'll never forget a couple of head scratchers that the megger found.... One
was a perfectly fine, 6' long piece of Orange #12 XHHW-2 that would only
pull 40 Megohms installed in EMT. Pulled it out and replaced it. Inspected
it for any visible flaws. None found. Not a scratch or scuff. Used it as a
training tool for my guys. Hung it on the wall over my desk as a handy
reminder. If anybody wants a picture...



The other was interesting, too. The very first PV system I ever installed.
Was shooting the DC circuits from the inverter all the way to the connector
on the output jumper cables at the modules. Megger showed dead short on one
wire. Fluke 79 on ohms showed clear. Hit it with the megger again. Dead
short. I'm known for being anal about conduit and wire installation, so this
was quite unexpected, not to mention a little embarrassing. This happened to
be a Solarex Millennia Integra system with an Omnion inverter and the array
happened to be scattered all over this roof. For those of you who who have
dealt with that situation, you'll understand what a cluster-*$#! that is...
Especially being my very first PV system and all... I wasn't anywhere near
confident that I had a clue by that point. All ready to see my first install
fire up and this happens.



It was my first install and I had 3 people getting paid prevailing wages to
learn... I was learning too, but I wasn't making anywhere near prevailing
wages, let me tell ya. Well, it was early January, late in the day and foggy
as foggy gets, but we went back onto the roof anyway. Yeah... Overtime for
everybody but me. We opened up the condulets and J-boxes for inspection.
Pulled all the wires up out of the J-boxes. Pulled the endcaps and ground
clips off (unique components of the Integra product). Couldn't find anything
suspicious. Shot it with the megger again, and it was all clear. But no sign
of anything that could have been shorted. We put everything back together
and shot it again. Dead short! Aiyeeeee!



Call it a day. Go home. I couldn't get back to that site until about the
same time the next day. Foggy again. Only took 1 helper with me this time.
We completely repeated the entire exercise, with exactly the same results.
By now, I was pretty sure this solar stuff wasn't my calling. I've always
been regarded as a gifted trouble-shooter and all I could say at this point
was that I didn't know _____! All signs pointed to it being associated with
one of the J-boxes or the endcaps or the ground clips, but there was NOT a
thing we could see. Oh, well. I would have to come back another day. When I
went back, I took the same helper and made sure I had all day if necessary
to fix the problem. No matter what it turned out to be. We planned to take
it apart 1 piece at a time and re-shoot it with the megger after each step.
I left my helper on the ground with the megger while I took it apart on the
roof, 1 screw at a time. Again.



Well, lo and behold, he hollers up that "It's clear" when I pulled the cover
off one of the 2-gang bell boxes. Hadn't moved a wire. Just took the cover
off. Let me tell ya, I stuck my nose and four eyes in that box real close,
but didn't touch any wires. The box was a tight fit with those big,
sealant-filled blue wire nuts that came with the Solarex Kit, but I still
couldn't see anything wierd.



"Shoot it again."



"All clear, boss."



I put the cover back on and installed all the screws. "Shoot it again."



"Dead short." We had a talk later about shouting things like "Dead short" on
the jobsite, but I won't get into all that right now.



I took out one of the cover screws. "Shoot it again." Same answer from the
ground.



I took out a second screw. "Shoot it again." This time the reply was
different. I took out the third screw and we repeated the process. Still
clear. And the fourth. Still clear. WTF? I lifted the cover for what seemed
like the hundredth time. I studied the nested wires, all neatly and
systematically put into what I had thought would be their final resting
place... Days before and time and time again at this point.



I began gently lifting the wires out so they all stood up like dandelions in
a spring lawn. I inspected them for the nth time. Looking for a stray strand
outside its protective hat. Nope. Overtightened wire nut with the spring or
a conductor coming out the tip? Nope. But what's this little, nearly
imperceptible dent in the side of this wire nut? As I looked closer, I could
see that it was round, flat bottomed and about the same diameter as a 6-32
screw. Hmmmm. I rolled the wires back into their resting position. Uh, huh.
This particular wire nut's natural home was directly under the cover screw
which had cleared the fault when removed and the dent lined up perfectly.
The screw could just barely be long enough to pierce the plastic and contact
the wire-spring.



I replaced the wire nut, repositioned the conductors to make sure we
wouldn't have a repeat, and buttoned up the J-box. I put the wirenut in my
pocket for later reference. One more megger shot proved the system to be all
clear. We could now energize the DC and do our Voc & Isc testing prior to
startup. Thank goodness the sun was shining. I wasn't happy about this whole
ordeal, but it was a good thing we caught it with the megger before we put
the power to it.



That wire nut became the first exhibit in what became my collection of
training materials for the "what can go wrong and why we do these
procedures" trainings. Verification that cover and mounting screws cannot
come in contact with energized equipment was officially put in the
checklist. All cover & mounting screws in all types of enclosures. There
would be no exceptions. There would be no excuses. I actually had to write
one guy up for a violation of this at one point. Good thing we caught that
one with the megger before putting the power to it.



I would posit that at least one of the recent PV fires would absolutely have
been prevented if the installer followed the procedure described above. Too
bad most don't. Kudos to those of you who do. It's only a matter of time
until more and more of these AVOIDABLE problems surface.



If you don't have a megger, get one. If you have one, use it! The Fluke 1520
is a nice unit. I recommend it over analog models. I cut my teeth with
analog gear, but really like my 1520. A lot! Rugged instrument that gives
you an actual number to write on your commissioning sheet. In addition to
Megohms, it also does VAC, Lo Ohms, Continuity, has a display backlight,
Lock and Zero functions and my favorite.... Battery Check! Reads out an
actual % value for your battery condition. Nice! Uses 4 "C" cells.



I hope more hands go up on this topic. Thanks for asking, Keith.



Peace and Palm Trees everybody,



Matt Lafferty



_____

From: re-wrenches-bounces at lists.re-wrenches.org
[mailto:re-wrenches-bounces at lists.re-wrenches.org] On Behalf Of Keith Cronin
Sent: Monday, April 27, 2009 2:37 PM
To: RE-Wrenches


Subject: [RE-wrenches] To Megger or not to Megger



Hi

I was wondering, by a show of hands, how many of you megger every project?

Do you have a cut off- like if it is "x" sized system, you will or decide to
opt out of performing this task?




_______________________________________________
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Matt Lafferty
2009-04-28 13:55:51 UTC
Permalink
RE: Suggested replacements for Fluke 1520 and "pricey meters"... Good News
below!

Another Wrench sent me a note off-list last night, asking how much a
"muggering" would cost. Here's what I sent him:

When I got that 1520 it was just over $600. I just checked online and find
that it's a discontinued item... Bummer!

Fluke recommends the 1587 or the 1507 or the 1503. They also mention the
1577, but it's an ugly stepsister, or maybe a retarded adopted relative, to
the 1587.

The 1587 is basically a multimeter that also has a <TEST> button to
discharge a high voltage shock into the sample under test... It runs about
$620 from standard distributors.
<http://us.fluke.com/usen/products/Fluke+1587+1577.htm?catalog_name=FlukeUni
tedStates>
http://us.fluke.com/usen/products/Fluke+1587+1577.htm?catalog_name=FlukeUnit
edStates You can get it for $522 here:
<http://www.testequipmentdepot.com/fluke/megohmmeters/1577_87.htm>
http://www.testequipmentdepot.com/fluke/megohmmeters/1577_87.htm NOTE: It
does not test at 10A in DMM mode which means it wouldn't be able to test
short-circuit current in strings. Don't bother with the 1577!

The 1507 & 1503 are more robust equipment. You can check them out here:
<http://us.fluke.com/usen/products/features.htm?cs_id=35391(FlukeProducts)&c
ategory=HMA(FlukeProducts>
http://us.fluke.com/usen/products/features.htm?cs_id=35391(FlukeProducts)&ca
tegory=HMA(FlukeProducts) While they do measure AC & DC Voltages to 600V as
well as some lower ohm & continuity work, they are really more tailored to
being a megger. The 1503 will suffice for most of what I expect you will get
into, but there are some features on the 1507 that might make it worth
considering. Mind you, I haven't looked at at price on either yet, so that
last comment may just be noises coming out my ass.

The 1507 has a Compare function which basically sets up a Pass/Fail value so
you can quickly run through repeated tests. This would be useful for doing
larger systems where you are testing dozens or hundreds of circuits at a
time. For my purposes, I want my guys to think a little more than "Buzz =
OK" and I want them to write an actual tested value down on a piece of paper
so this is not a big plus to me.

The 1507 also does Polarization Index and Absorption Ratios. These are more
advanced di-electric tests that you are not likely to need in smaller scale
PV. Use of these features would come into play when playing with real
high-voltage gear or transformers. Might also come into play on
super-sensitive equipment. They might also be used to assess older or aging
underground or overhead feeders.

The 1507 & 1503 both have an Earth Bond Resistance function which is likely
to become more of an issue in the future. This feature lets you test the
resistance between a grounding electrode or a grounding electrode conductor
and actual earth. Another use for this feature would be to set the output to
1kV, connect the alligator jaw to one of Mike Gripando's extremities and use
the probe lead as a tongue depressor while you push <TEST>. This feature
used to be in a single-purpose tester that ran >$2K. They also both have
backlit displays which comes in real handy out in the field.

The primary features you want are: 500V & 1kV Test Voltage and 2 Gohms
(2,000 Megaohms) or above for the top end of the range. Any of the 3 meet
this spec.

Well, I just checked prices for the 1503 & 1507 and I'm pleasantly
surprised. The 1503 ranges from about $291-$370. Here's the place I found it
for $291 <http://www.testequipmentdepot.com/fluke/megohmmeters/1503.htm>
http://www.testequipmentdepot.com/fluke/megohmmeters/1503.htm That's marked
down from the regular price of $342.

The 1507 ranges from about $385 to $500. Here's where I found it for $385...
<http://www.testequipmentdepot.com/fluke/megohmmeters/1507.htm>
http://www.testequipmentdepot.com/fluke/megohmmeters/1507.htm That's a
special price, for you only, down from $454.

All things considered if I were in your shoes, I'd go for the 1503. That
give you a solid megger that you can dedicate to that purpose for a
reasonale muggering. If it were me, in Matt's shoes... Oh, what am I saying?
I've already got mine and I just found out I paid too much for it! But I
have Battery Check... Neener neener neener!

Be safe out there!

Matt Lafferty


I hope more hands go up on this topic. Thanks for asking, Keith.

Peace and Palm Trees everybody,

Matt Lafferty


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robert ellison
2009-04-28 14:11:55 UTC
Permalink
http://www.testequipmentdepot.com/fluke/pricelist.htm Has a 1507 for $385.06




On Tue, Apr 28, 2009 at 9:55 AM, Matt Lafferty <gilligan06 at gmail.com> wrote:

> RE: Suggested replacements for Fluke 1520 and "pricey meters"... Good
> News below!
>
> Another Wrench sent me a note off-list last night, asking how much a
> "muggering" would cost. Here's what I sent him:
>
> When I got that 1520 it was just over $600. I just checked online and find
> that it's a discontinued item... Bummer!
>
> Fluke recommends the 1587 or the 1507 or the 1503. They also mention the
> 1577, but it's an ugly stepsister, or maybe a retarded adopted relative, to
> the 1587.
>
> The 1587 is basically a multimeter that also has a <TEST> button to
> discharge a high voltage shock into the sample under test... It runs about
> $620 from standard distributors.
> http://us.fluke.com/usen/products/Fluke+1587+1577.htm?catalog_name=FlukeUnitedStates
> You can get it for $522 here:
> http://www.testequipmentdepot.com/fluke/megohmmeters/1577_87.htm NOTE: It
> does not test at 10A in DMM mode which means it wouldn't be able to test
> short-circuit current in strings. Don't bother with the 1577!
>
> The 1507 & 1503 are more robust equipment. You can check them out here:
> http://us.fluke.com/usen/products/features.htm?cs_id=35391(FlukeProducts)&category=HMA(FlukeProducts)
> While they do measure AC & DC Voltages to 600V as well as some lower ohm &
> continuity work, they are really more tailored to being a megger. The 1503
> will suffice for most of what I expect you will get into, but there are some
> features on the 1507 that might make it worth considering. Mind you, I
> haven't looked at at price on either yet, so that last comment may just be
> noises coming out my ass.
>
> The 1507 has a Compare function which basically sets up a Pass/Fail value
> so you can quickly run through repeated tests. This would be useful for
> doing larger systems where you are testing dozens or hundreds of circuits at
> a time. For my purposes, I want my guys to think a little more than "Buzz =
> OK" and I want them to write an actual tested value down on a piece of paper
> so this is not a big plus to me.
>
> The 1507 also does Polarization Index and Absorption Ratios. These are more
> advanced di-electric tests that you are not likely to need in smaller scale
> PV. Use of these features would come into play when playing with real
> high-voltage gear or transformers. Might also come into play on
> super-sensitive equipment. They might also be used to assess older or aging
> underground or overhead feeders.
>
> The 1507 & 1503 both have an Earth Bond Resistance function which is likely
> to become more of an issue in the future. This feature lets you test the
> resistance between a grounding electrode or a grounding electrode conductor
> and actual earth. Another use for this feature would be to set the output to
> 1kV, connect the alligator jaw to one of Mike Gripando's extremities and use
> the probe lead as a tongue depressor while you push <TEST>. This feature
> used to be in a single-purpose tester that ran >$2K. They also both have
> backlit displays which comes in real handy out in the field.
>
> The primary features you want are: 500V & 1kV Test Voltage and 2 Gohms
> (2,000 Megaohms) or above for the top end of the range. Any of the 3 meet
> this spec.
>
> Well, I just checked prices for the 1503 & 1507 and I'm pleasantly
> surprised. The 1503 ranges from about $291-$370. Here's the place I found
> it for *$291 *
> http://www.testequipmentdepot.com/fluke/megohmmeters/1503.htm That's
> marked down from the regular price of $342.
>
> The 1507 ranges from about $385 to $500. Here's where I found it for *$385...
> *http://www.testequipmentdepot.com/fluke/megohmmeters/1507.htm That's a
> special price, for you only, down from $454.
>
> All things considered if I were in your shoes, I'd go for the 1503. That
> give you a solid megger that you can dedicate to that purpose for a
> reasonale muggering. If it were me, in Matt's shoes... Oh, what am I
> saying? I've already got mine and I just found out I paid too much for it!
> But I have Battery Check... Neener neener neener!
>
> Be safe out there!
>
> Matt Lafferty
>
>
>> I hope more hands go up on this topic. Thanks for asking, Keith.
>>
>> Peace and Palm Trees everybody,
>>
>> Matt Lafferty
>>
>
>
> _______________________________________________
> List sponsored by Home Power magazine
>
> List Address: RE-wrenches at lists.re-wrenches.org
>
> Options & settings:
> http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org
>
> List-Archive:
> http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org
>
> List rules & etiquette:
> www.re-wrenches.org/etiquette.htm
>
> Check out participant bios:
> www.members.re-wrenches.org
>
>
>
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robert ellison
2009-04-28 14:14:01 UTC
Permalink
Sorry it's already covered. Thats what I get for not reading all the way to
the bottom of the posts.

Bob

On Tue, Apr 28, 2009 at 10:11 AM, robert ellison <reellison at gmail.com>wrote:

> http://www.testequipmentdepot.com/fluke/pricelist.htm Has a 1507 for
> $385.06
>
>
>
>
> On Tue, Apr 28, 2009 at 9:55 AM, Matt Lafferty <gilligan06 at gmail.com>wrote:
>
>> RE: Suggested replacements for Fluke 1520 and "pricey meters"... Good
>> News below!
>>
>> Another Wrench sent me a note off-list last night, asking how much a
>> "muggering" would cost. Here's what I sent him:
>>
>> When I got that 1520 it was just over $600. I just checked online and find
>> that it's a discontinued item... Bummer!
>>
>> Fluke recommends the 1587 or the 1507 or the 1503. They also mention the
>> 1577, but it's an ugly stepsister, or maybe a retarded adopted relative, to
>> the 1587.
>>
>> The 1587 is basically a multimeter that also has a <TEST> button to
>> discharge a high voltage shock into the sample under test... It runs about
>> $620 from standard distributors.
>> http://us.fluke.com/usen/products/Fluke+1587+1577.htm?catalog_name=FlukeUnitedStates
>> You can get it for $522 here:
>> http://www.testequipmentdepot.com/fluke/megohmmeters/1577_87.htm NOTE:
>> It does not test at 10A in DMM mode which means it wouldn't be able to test
>> short-circuit current in strings. Don't bother with the 1577!
>>
>> The 1507 & 1503 are more robust equipment. You can check them out here:
>> http://us.fluke.com/usen/products/features.htm?cs_id=35391(FlukeProducts)&category=HMA(FlukeProducts)
>> While they do measure AC & DC Voltages to 600V as well as some lower ohm &
>> continuity work, they are really more tailored to being a megger. The 1503
>> will suffice for most of what I expect you will get into, but there are some
>> features on the 1507 that might make it worth considering. Mind you, I
>> haven't looked at at price on either yet, so that last comment may just be
>> noises coming out my ass.
>>
>> The 1507 has a Compare function which basically sets up a Pass/Fail value
>> so you can quickly run through repeated tests. This would be useful for
>> doing larger systems where you are testing dozens or hundreds of circuits at
>> a time. For my purposes, I want my guys to think a little more than "Buzz =
>> OK" and I want them to write an actual tested value down on a piece of paper
>> so this is not a big plus to me.
>>
>> The 1507 also does Polarization Index and Absorption Ratios. These are
>> more advanced di-electric tests that you are not likely to need in smaller
>> scale PV. Use of these features would come into play when playing with real
>> high-voltage gear or transformers. Might also come into play on
>> super-sensitive equipment. They might also be used to assess older or aging
>> underground or overhead feeders.
>>
>> The 1507 & 1503 both have an Earth Bond Resistance function which is
>> likely to become more of an issue in the future. This feature lets you test
>> the resistance between a grounding electrode or a grounding electrode
>> conductor and actual earth. Another use for this feature would be to set the
>> output to 1kV, connect the alligator jaw to one of Mike Gripando's
>> extremities and use the probe lead as a tongue depressor while you push
>> <TEST>. This feature used to be in a single-purpose tester that ran >$2K.
>> They also both have backlit displays which comes in real handy out in the
>> field.
>>
>> The primary features you want are: 500V & 1kV Test Voltage and 2 Gohms
>> (2,000 Megaohms) or above for the top end of the range. Any of the 3 meet
>> this spec.
>>
>> Well, I just checked prices for the 1503 & 1507 and I'm pleasantly
>> surprised. The 1503 ranges from about $291-$370. Here's the place I found
>> it for *$291 *
>> http://www.testequipmentdepot.com/fluke/megohmmeters/1503.htm That's
>> marked down from the regular price of $342.
>>
>> The 1507 ranges from about $385 to $500. Here's where I found it for *$385...
>> *http://www.testequipmentdepot.com/fluke/megohmmeters/1507.htm That's a
>> special price, for you only, down from $454.
>>
>> All things considered if I were in your shoes, I'd go for the 1503. That
>> give you a solid megger that you can dedicate to that purpose for a
>> reasonale muggering. If it were me, in Matt's shoes... Oh, what am I
>> saying? I've already got mine and I just found out I paid too much for it!
>> But I have Battery Check... Neener neener neener!
>>
>> Be safe out there!
>>
>> Matt Lafferty
>>
>>
>>> I hope more hands go up on this topic. Thanks for asking, Keith.
>>>
>>> Peace and Palm Trees everybody,
>>>
>>> Matt Lafferty
>>>
>>
>>
>> _______________________________________________
>> List sponsored by Home Power magazine
>>
>> List Address: RE-wrenches at lists.re-wrenches.org
>>
>> Options & settings:
>> http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org
>>
>> List-Archive:
>> http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org
>>
>> List rules & etiquette:
>> www.re-wrenches.org/etiquette.htm
>>
>> Check out participant bios:
>> www.members.re-wrenches.org
>>
>>
>>
>
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robert ellison
2009-04-28 14:14:01 UTC
Permalink
Sorry it's already covered. Thats what I get for not reading all the way to
the bottom of the posts.

Bob

On Tue, Apr 28, 2009 at 10:11 AM, robert ellison <reellison at gmail.com>wrote:

> http://www.testequipmentdepot.com/fluke/pricelist.htm Has a 1507 for
> $385.06
>
>
>
>
> On Tue, Apr 28, 2009 at 9:55 AM, Matt Lafferty <gilligan06 at gmail.com>wrote:
>
>> RE: Suggested replacements for Fluke 1520 and "pricey meters"... Good
>> News below!
>>
>> Another Wrench sent me a note off-list last night, asking how much a
>> "muggering" would cost. Here's what I sent him:
>>
>> When I got that 1520 it was just over $600. I just checked online and find
>> that it's a discontinued item... Bummer!
>>
>> Fluke recommends the 1587 or the 1507 or the 1503. They also mention the
>> 1577, but it's an ugly stepsister, or maybe a retarded adopted relative, to
>> the 1587.
>>
>> The 1587 is basically a multimeter that also has a <TEST> button to
>> discharge a high voltage shock into the sample under test... It runs about
>> $620 from standard distributors.
>> http://us.fluke.com/usen/products/Fluke+1587+1577.htm?catalog_name=FlukeUnitedStates
>> You can get it for $522 here:
>> http://www.testequipmentdepot.com/fluke/megohmmeters/1577_87.htm NOTE:
>> It does not test at 10A in DMM mode which means it wouldn't be able to test
>> short-circuit current in strings. Don't bother with the 1577!
>>
>> The 1507 & 1503 are more robust equipment. You can check them out here:
>> http://us.fluke.com/usen/products/features.htm?cs_id=35391(FlukeProducts)&category=HMA(FlukeProducts)
>> While they do measure AC & DC Voltages to 600V as well as some lower ohm &
>> continuity work, they are really more tailored to being a megger. The 1503
>> will suffice for most of what I expect you will get into, but there are some
>> features on the 1507 that might make it worth considering. Mind you, I
>> haven't looked at at price on either yet, so that last comment may just be
>> noises coming out my ass.
>>
>> The 1507 has a Compare function which basically sets up a Pass/Fail value
>> so you can quickly run through repeated tests. This would be useful for
>> doing larger systems where you are testing dozens or hundreds of circuits at
>> a time. For my purposes, I want my guys to think a little more than "Buzz =
>> OK" and I want them to write an actual tested value down on a piece of paper
>> so this is not a big plus to me.
>>
>> The 1507 also does Polarization Index and Absorption Ratios. These are
>> more advanced di-electric tests that you are not likely to need in smaller
>> scale PV. Use of these features would come into play when playing with real
>> high-voltage gear or transformers. Might also come into play on
>> super-sensitive equipment. They might also be used to assess older or aging
>> underground or overhead feeders.
>>
>> The 1507 & 1503 both have an Earth Bond Resistance function which is
>> likely to become more of an issue in the future. This feature lets you test
>> the resistance between a grounding electrode or a grounding electrode
>> conductor and actual earth. Another use for this feature would be to set the
>> output to 1kV, connect the alligator jaw to one of Mike Gripando's
>> extremities and use the probe lead as a tongue depressor while you push
>> <TEST>. This feature used to be in a single-purpose tester that ran >$2K.
>> They also both have backlit displays which comes in real handy out in the
>> field.
>>
>> The primary features you want are: 500V & 1kV Test Voltage and 2 Gohms
>> (2,000 Megaohms) or above for the top end of the range. Any of the 3 meet
>> this spec.
>>
>> Well, I just checked prices for the 1503 & 1507 and I'm pleasantly
>> surprised. The 1503 ranges from about $291-$370. Here's the place I found
>> it for *$291 *
>> http://www.testequipmentdepot.com/fluke/megohmmeters/1503.htm That's
>> marked down from the regular price of $342.
>>
>> The 1507 ranges from about $385 to $500. Here's where I found it for *$385...
>> *http://www.testequipmentdepot.com/fluke/megohmmeters/1507.htm That's a
>> special price, for you only, down from $454.
>>
>> All things considered if I were in your shoes, I'd go for the 1503. That
>> give you a solid megger that you can dedicate to that purpose for a
>> reasonale muggering. If it were me, in Matt's shoes... Oh, what am I
>> saying? I've already got mine and I just found out I paid too much for it!
>> But I have Battery Check... Neener neener neener!
>>
>> Be safe out there!
>>
>> Matt Lafferty
>>
>>
>>> I hope more hands go up on this topic. Thanks for asking, Keith.
>>>
>>> Peace and Palm Trees everybody,
>>>
>>> Matt Lafferty
>>>
>>
>>
>> _______________________________________________
>> List sponsored by Home Power magazine
>>
>> List Address: RE-wrenches at lists.re-wrenches.org
>>
>> Options & settings:
>> http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org
>>
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>> http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org
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>
-------------- next part --------------
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David Palumbo
2009-04-28 14:59:20 UTC
Permalink
Matt,



"Muggering", I think that will catch on. The last post, I think, ol' Uncle
Bill Brooks (4/13/09 8:17 PM) had on this topic raised a concern about "not
having enough resolution in the low impedance area. PV arrays can have an
impedance to ground of a slow as 2kOhms. A resolution of 0.1MOhms will
likely not cut it." Bill went on to say that he had bought a cheaper meter
to test out "for fun". Some of us do enjoy "muggering around".



So my question is. Do the Fluke 1503's and 1507's have enough resolution
in the low range?



Dave



From: re-wrenches-bounces at lists.re-wrenches.org
[mailto:re-wrenches-bounces at lists.re-wrenches.org] On Behalf Of Matt
Lafferty
Sent: Tuesday, April 28, 2009 9:56 AM
To: 'RE-wrenches'
Subject: Re: [RE-wrenches] To Megger or not to Megger



RE: Suggested replacements for Fluke 1520 and "pricey meters"... Good News
below!



Another Wrench sent me a note off-list last night, asking how much a
"muggering" would cost. Here's what I sent him:



When I got that 1520 it was just over $600. I just checked online and find
that it's a discontinued item... Bummer!



Fluke recommends the 1587 or the 1507 or the 1503. They also mention the
1577, but it's an ugly stepsister, or maybe a retarded adopted relative, to
the 1587.



The 1587 is basically a multimeter that also has a <TEST> button to
discharge a high voltage shock into the sample under test... It runs about
$620 from standard distributors.
<http://us.fluke.com/usen/products/Fluke+1587+1577.htm?catalog_name=FlukeUni
tedStates>
http://us.fluke.com/usen/products/Fluke+1587+1577.htm?catalog_name=FlukeUnit
edStates You can get it for $522 here:

<http://www.testequipmentdepot.com/fluke/megohmmeters/1577_87.htm>
http://www.testequipmentdepot.com/fluke/megohmmeters/1577_87.htm NOTE: It
does not test at 10A in DMM mode which means it wouldn't be able to test
short-circuit current in strings. Don't bother with the 1577!



The 1507 & 1503 are more robust equipment. You can check them out here:
<http://us.fluke.com/usen/products/features.htm?cs_id=35391(FlukeProducts)&c
ategory=HMA(FlukeProducts>
http://us.fluke.com/usen/products/features.htm?cs_id=35391(FlukeProducts)&ca
tegory=HMA(FlukeProducts) While they do measure AC & DC Voltages to 600V as
well as some lower ohm & continuity work, they are really more tailored to
being a megger. The 1503 will suffice for most of what I expect you will get
into, but there are some features on the 1507 that might make it worth
considering. Mind you, I haven't looked at at price on either yet, so that
last comment may just be noises coming out my ass.



The 1507 has a Compare function which basically sets up a Pass/Fail value so
you can quickly run through repeated tests. This would be useful for doing
larger systems where you are testing dozens or hundreds of circuits at a
time. For my purposes, I want my guys to think a little more than "Buzz =
OK" and I want them to write an actual tested value down on a piece of paper
so this is not a big plus to me.



The 1507 also does Polarization Index and Absorption Ratios. These are more
advanced di-electric tests that you are not likely to need in smaller scale
PV. Use of these features would come into play when playing with real
high-voltage gear or transformers. Might also come into play on
super-sensitive equipment. They might also be used to assess older or aging
underground or overhead feeders.



The 1507 & 1503 both have an Earth Bond Resistance function which is likely
to become more of an issue in the future. This feature lets you test the
resistance between a grounding electrode or a grounding electrode conductor
and actual earth. Another use for this feature would be to set the output to
1kV, connect the alligator jaw to one of Mike Gripando's extremities and use
the probe lead as a tongue depressor while you push <TEST>. This feature
used to be in a single-purpose tester that ran >$2K. They also both have
backlit displays which comes in real handy out in the field.



The primary features you want are: 500V & 1kV Test Voltage and 2 Gohms
(2,000 Megaohms) or above for the top end of the range. Any of the 3 meet
this spec.



Well, I just checked prices for the 1503 & 1507 and I'm pleasantly
surprised. The 1503 ranges from about $291-$370. Here's the place I found it
for $291 <http://www.testequipmentdepot.com/fluke/megohmmeters/1503.htm>
http://www.testequipmentdepot.com/fluke/megohmmeters/1503.htm That's marked
down from the regular price of $342.



The 1507 ranges from about $385 to $500. Here's where I found it for $385...
<http://www.testequipmentdepot.com/fluke/megohmmeters/1507.htm>
http://www.testequipmentdepot.com/fluke/megohmmeters/1507.htm That's a
special price, for you only, down from $454.



All things considered if I were in your shoes, I'd go for the 1503. That
give you a solid megger that you can dedicate to that purpose for a
reasonale muggering. If it were me, in Matt's shoes... Oh, what am I saying?
I've already got mine and I just found out I paid too much for it! But I
have Battery Check... Neener neener neener!



Be safe out there!



Matt Lafferty



I hope more hands go up on this topic. Thanks for asking, Keith.



Peace and Palm Trees everybody,



Matt Lafferty



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Bill Brooks
2009-04-28 17:39:44 UTC
Permalink
Dave,



The issue is definitely resolution. The cool thing about the Fluke 1520 is
that it goes down to 0.001MOhms (1000 Ohms). That is the resolution you are
looking for. Neither of the current Flukes go low enough. That is why I'm
going into the field later this week to see how a 0.1MOhm meter stacks up to
finding faults-I have an array with a pesky fault that should make it fun.



Many arrays will ring out as a faulted array when, in fact, everything is
fine. This is especially true of a-Si arrays with low quality glass. They
are very leaky. I'll keep looking and report back on a recommendation for
Christmas shopping.



Just to add punctuation to this thread, I always recommend that contractors
megger their arrays, because it has saved my butt several times. Also, with
exterior wiring systems it is even more important. The problem in the early
days is that people would whine about the $600-$1000 price tag. In my
opinion, that argument is gone. With contractors routinely putting down
$1400 for a SunEye, the value of a good megger is similar and costs less.



Bill.



From: re-wrenches-bounces at lists.re-wrenches.org
[mailto:re-wrenches-bounces at lists.re-wrenches.org] On Behalf Of David
Palumbo
Sent: Tuesday, April 28, 2009 7:59 AM
To: gilligan06 at gmail.com; 'RE-wrenches'
Subject: Re: [RE-wrenches] To Megger or not to Megger



Matt,



"Muggering", I think that will catch on. The last post, I think, ol' Uncle
Bill Brooks (4/13/09 8:17 PM) had on this topic raised a concern about "not
having enough resolution in the low impedance area. PV arrays can have an
impedance to ground of a slow as 2kOhms. A resolution of 0.1MOhms will
likely not cut it." Bill went on to say that he had bought a cheaper meter
to test out "for fun". Some of us do enjoy "muggering around".



So my question is. Do the Fluke 1503's and 1507's have enough resolution
in the low range?



Dave



From: re-wrenches-bounces at lists.re-wrenches.org
[mailto:re-wrenches-bounces at lists.re-wrenches.org] On Behalf Of Matt
Lafferty
Sent: Tuesday, April 28, 2009 9:56 AM
To: 'RE-wrenches'
Subject: Re: [RE-wrenches] To Megger or not to Megger



RE: Suggested replacements for Fluke 1520 and "pricey meters"... Good News
below!



Another Wrench sent me a note off-list last night, asking how much a
"muggering" would cost. Here's what I sent him:



When I got that 1520 it was just over $600. I just checked online and find
that it's a discontinued item... Bummer!



Fluke recommends the 1587 or the 1507 or the 1503. They also mention the
1577, but it's an ugly stepsister, or maybe a retarded adopted relative, to
the 1587.



The 1587 is basically a multimeter that also has a <TEST> button to
discharge a high voltage shock into the sample under test... It runs about
$620 from standard distributors.
<http://us.fluke.com/usen/products/Fluke+1587+1577.htm?catalog_name=FlukeUni
tedStates>
http://us.fluke.com/usen/products/Fluke+1587+1577.htm?catalog_name=FlukeUnit
edStates You can get it for $522 here:

<http://www.testequipmentdepot.com/fluke/megohmmeters/1577_87.htm>
http://www.testequipmentdepot.com/fluke/megohmmeters/1577_87.htm NOTE: It
does not test at 10A in DMM mode which means it wouldn't be able to test
short-circuit current in strings. Don't bother with the 1577!



The 1507 & 1503 are more robust equipment. You can check them out here:
<http://us.fluke.com/usen/products/features.htm?cs_id=35391(FlukeProducts)&c
ategory=HMA(FlukeProducts>
http://us.fluke.com/usen/products/features.htm?cs_id=35391(FlukeProducts)&ca
tegory=HMA(FlukeProducts) While they do measure AC & DC Voltages to 600V as
well as some lower ohm & continuity work, they are really more tailored to
being a megger. The 1503 will suffice for most of what I expect you will get
into, but there are some features on the 1507 that might make it worth
considering. Mind you, I haven't looked at at price on either yet, so that
last comment may just be noises coming out my ass.



The 1507 has a Compare function which basically sets up a Pass/Fail value so
you can quickly run through repeated tests. This would be useful for doing
larger systems where you are testing dozens or hundreds of circuits at a
time. For my purposes, I want my guys to think a little more than "Buzz =
OK" and I want them to write an actual tested value down on a piece of paper
so this is not a big plus to me.



The 1507 also does Polarization Index and Absorption Ratios. These are more
advanced di-electric tests that you are not likely to need in smaller scale
PV. Use of these features would come into play when playing with real
high-voltage gear or transformers. Might also come into play on
super-sensitive equipment. They might also be used to assess older or aging
underground or overhead feeders.



The 1507 & 1503 both have an Earth Bond Resistance function which is likely
to become more of an issue in the future. This feature lets you test the
resistance between a grounding electrode or a grounding electrode conductor
and actual earth. Another use for this feature would be to set the output to
1kV, connect the alligator jaw to one of Mike Gripando's extremities and use
the probe lead as a tongue depressor while you push <TEST>. This feature
used to be in a single-purpose tester that ran >$2K. They also both have
backlit displays which comes in real handy out in the field.



The primary features you want are: 500V & 1kV Test Voltage and 2 Gohms
(2,000 Megaohms) or above for the top end of the range. Any of the 3 meet
this spec.



Well, I just checked prices for the 1503 & 1507 and I'm pleasantly
surprised. The 1503 ranges from about $291-$370. Here's the place I found it
for $291 <http://www.testequipmentdepot.com/fluke/megohmmeters/1503.htm>
http://www.testequipmentdepot.com/fluke/megohmmeters/1503.htm That's marked
down from the regular price of $342.



The 1507 ranges from about $385 to $500. Here's where I found it for $385...
<http://www.testequipmentdepot.com/fluke/megohmmeters/1507.htm>
http://www.testequipmentdepot.com/fluke/megohmmeters/1507.htm That's a
special price, for you only, down from $454.



All things considered if I were in your shoes, I'd go for the 1503. That
give you a solid megger that you can dedicate to that purpose for a
reasonale muggering. If it were me, in Matt's shoes... Oh, what am I saying?
I've already got mine and I just found out I paid too much for it! But I
have Battery Check... Neener neener neener!



Be safe out there!



Matt Lafferty



I hope more hands go up on this topic. Thanks for asking, Keith.



Peace and Palm Trees everybody,



Matt Lafferty



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Matt Lafferty
2009-04-28 19:48:59 UTC
Permalink
Hi Bill,

I so totally agree with your comment about the price of these being a
non-issue, all things considered. As long as we're getting the features we
need in the sub-$750 range, that is. When it comes down to it, this is
meaningful safety and reliability stuff. No slam to the Bolinas crew, but
the SunEye is a lettle less important than that. Unless, of course, you
shade a certain type of module and the bypass diode fails and the thing
ignites.... Then you could make a case for the SunEye being prudent for
Disqualification of location, which would mean there wouldn't be a need for
the megger on that non-job.

Perhaps you could address a couple of aspects that I have questioned for a
long time.

First of all, is it or is it not true that megger testing an array at 1kV
may result in flaky-bias diodes (my term) if polarity of test leads is
incorrect relative the array and/or the array wiring is grounded/not
grounded during the test? (The root of my policy to NOT megger arrays unless
I have specific procedure provided by the mfr... Me no wanna get in a "you
meggered it so you don't have a warranty" conversation if ya know of what I
speak.)

Which of the mainstream module manufacturers are publishing a procedure for
megger testing their arrays for use by installers?

Are these being published for wet or dry testing? Both?

Which of these manufacturers are supplying this documentation in a publicly
accessible manner? (Asked quite a few sales reps over the years and only 1
ever produced a document... I have been able to get some from engineers in
the factory, but this was generally when I had a big stick to pound on
somebody's desk.)

Why don't most installers and distributors know this documentation exists or
understand the procedure at this point?

Yeah, it's one of those thorny issues with me. Maybe we can get our heads
together to steamroll a solution to the above. Happy to take the subject up
off-list if you like.

On to today's question regarding resolution....

When you are measuring an array, why is the resolution so critical?
What value or value range do you believe constitutes a Pass on a quality Csi
product?
How about Asi / CdTe with crappy glass?
How about Asi with Tefcel?
Wet? Dry?
Does your answer change relative the capacity of the array portion under
test?
Does the answer change with temperature &/or relative humidity?
Does the answer change relative test voltage compared to array VOC?

What I'm getting at is, unless the minimum "Pass" value is a very low number
for the test setup, say 200K - 2M, or has a very narrow "Pass" range, a
super-fine resolution shouldn't be that critical. On the few occasions back
in the day when I actually meggered arrays, I used an analog megger. Top end
range @ 1kV was 250M. My recollection is that these things pulled 15M or
better, but I can't really testify to that... Fuzzy memory on the actual
values. I'd have to dig through some deep stacks of paperwork to find out if
I have any archives of the tests, and I'm not gonna do that for this post.
Had to submit the test results to SMUD (can't find them) and the mfrs.
Nobody ever said, "Hey. Close your other eye and tell me what it says." When
I asked what values would be appropriate, all I ever got was, "Just like you
got here. These are good." Never could nail them down and, frankly, never
got the idea that they were all-to-happy having installers owning meggers.

I'm with you on testing the array and module interconnects for leakage.
Really. But, if the arrays rings out as "faulted" when it's really "OK", why
bother? What are you looking for? If the resistance is that low, maybe we
should be using a "Kohmer" for the arrays and a Megger for the wiring &
equpment bussing. If you're getting such a low resistance, aren't you
picking it up with a "Static" test... Would the Earth Bond Resistance
function of the 1507 & 1503 be sufficient for these situations?
http://us.fluke.com/usen/products/specifications.htm?cs_id=35391(FlukeProduc
ts)
<http://us.fluke.com/usen/products/specifications.htm?cs_id=35391(FlukeProdu
cts)&category=HMA(FlukeProducts> &category=HMA(FlukeProducts) This is
basically a voltage shot like a megger, but measures resistance in the <20k
range. Resolution very nice there! This tester has a gap between 20k & 100k
(0.1M).

>From a "reasonable resolution" perspective, I think the gap is more like 20k
to 2M. Anything over 2M, the 0.1M resolution should be fine. If the array is
that close to failing, fail it and tell the mfr to start making some decent
glass. They might understand it better this way: ??

Dunno. I think it comes down to figuring out what ranges equal "Pass" for
the application and going from there. Will look forward to what you find in
your side-by-sides later this week. Please do post back. With a basic
description of the glass-type, mounting, wire-management, test results and
findings, if you can.

I'm gonna hang onto my 1520... If anybody wants to see what one looks like
with a 100% Battery Level, let me know... I'll hold it up in front of my
webcam for ya!

No Ground Faults!

Matt Lafferty

_____

From: re-wrenches-bounces at lists.re-wrenches.org
[mailto:re-wrenches-bounces at lists.re-wrenches.org] On Behalf Of Bill Brooks
Sent: Tuesday, April 28, 2009 10:40 AM
To: 'RE-wrenches'
Subject: Re: [RE-wrenches] To Megger or not to Megger



Dave,



The issue is definitely resolution. The cool thing about the Fluke 1520 is
that it goes down to 0.001MOhms (1000 Ohms). That is the resolution you are
looking for. Neither of the current Flukes go low enough. That is why I?m
going into the field later this week to see how a 0.1MOhm meter stacks up to
finding faults?I have an array with a pesky fault that should make it fun.



Many arrays will ring out as a faulted array when, in fact, everything is
fine. This is especially true of a-Si arrays with low quality glass. They
are very leaky. I?ll keep looking and report back on a recommendation for
Christmas shopping.



Just to add punctuation to this thread, I always recommend that contractors
megger their arrays, because it has saved my butt several times. Also, with
exterior wiring systems it is even more important. The problem in the early
days is that people would whine about the $600-$1000 price tag. In my
opinion, that argument is gone. With contractors routinely putting down
$1400 for a SunEye, the value of a good megger is similar and costs less.



Bill.



From: re-wrenches-bounces at lists.re-wrenches.org
[mailto:re-wrenches-bounces at lists.re-wrenches.org] On Behalf Of David
Palumbo
Sent: Tuesday, April 28, 2009 7:59 AM
To: gilligan06 at gmail.com; 'RE-wrenches'
Subject: Re: [RE-wrenches] To Megger or not to Megger



Matt,



?Muggering?, I think that will catch on. The last post, I think, ol?
Uncle Bill Brooks (4/13/09 8:17 PM) had on this topic raised a concern about
?not having enough resolution in the low impedance area. PV arrays can have
an impedance to ground of a slow as 2kOhms. A resolution of 0.1MOhms will
likely not cut it.? Bill went on to say that he had bought a cheaper meter
to test out ?for fun?. Some of us do enjoy ?muggering around?.



So my question is. Do the Fluke 1503?s and 1507?s have enough resolution
in the low range?



Dave



From: re-wrenches-bounces at lists.re-wrenches.org
[mailto:re-wrenches-bounces at lists.re-wrenches.org] On Behalf Of Matt
Lafferty
Sent: Tuesday, April 28, 2009 9:56 AM
To: 'RE-wrenches'
Subject: Re: [RE-wrenches] To Megger or not to Megger



RE: Suggested replacements for Fluke 1520 and "pricey meters"... Good News
below!



Another Wrench sent me a note off-list last night, asking how much a
"muggering" would cost. Here's what I sent him:



When I got that 1520 it was just over $600. I just checked online and find
that it's a discontinued item... Bummer!



Fluke recommends the 1587 or the 1507 or the 1503. They also mention the
1577, but it's an ugly stepsister, or maybe a retarded adopted relative, to
the 1587.



The 1587 is basically a multimeter that also has a <TEST> button to
discharge a high voltage shock into the sample under test... It runs about
$620 from standard distributors.
<http://us.fluke.com/usen/products/Fluke+1587+1577.htm?catalog_name=FlukeUni
tedStates>
http://us.fluke.com/usen/products/Fluke+1587+1577.htm?catalog_name=FlukeUnit
edStates You can get it for $522 here:

<http://www.testequipmentdepot.com/fluke/megohmmeters/1577_87.htm>
http://www.testequipmentdepot.com/fluke/megohmmeters/1577_87.htm NOTE: It
does not test at 10A in DMM mode which means it wouldn't be able to test
short-circuit current in strings. Don't bother with the 1577!



The 1507 & 1503 are more robust equipment. You can check them out here:
<http://us.fluke.com/usen/products/features.htm?cs_id=35391(FlukeProducts)&c
ategory=HMA(FlukeProducts>
http://us.fluke.com/usen/products/features.htm?cs_id=35391(FlukeProducts)&ca
tegory=HMA(FlukeProducts) While they do measure AC & DC Voltages to 600V as
well as some lower ohm & continuity work, they are really more tailored to
being a megger. The 1503 will suffice for most of what I expect you will get
into, but there are some features on the 1507 that might make it worth
considering. Mind you, I haven't looked at at price on either yet, so that
last comment may just be noises coming out my ass.



The 1507 has a Compare function which basically sets up a Pass/Fail value so
you can quickly run through repeated tests. This would be useful for doing
larger systems where you are testing dozens or hundreds of circuits at a
time. For my purposes, I want my guys to think a little more than "Buzz =
OK" and I want them to write an actual tested value down on a piece of paper
so this is not a big plus to me.



The 1507 also does Polarization Index and Absorption Ratios. These are more
advanced di-electric tests that you are not likely to need in smaller scale
PV. Use of these features would come into play when playing with real
high-voltage gear or transformers. Might also come into play on
super-sensitive equipment. They might also be used to assess older or aging
underground or overhead feeders.



The 1507 & 1503 both have an Earth Bond Resistance function which is likely
to become more of an issue in the future. This feature lets you test the
resistance between a grounding electrode or a grounding electrode conductor
and actual earth. Another use for this feature would be to set the output to
1kV, connect the alligator jaw to one of <Insert name of your
least-favorite building official here> extremities and use the probe lead as
a tongue depressor while you push <TEST>. This feature used to be in a
single-purpose tester that ran >$2K. They also both have backlit displays
which comes in real handy out in the field.



The primary features you want are: 500V & 1kV Test Voltage and 2 Gohms
(2,000 Megaohms) or above for the top end of the range. Any of the 3 meet
this spec.



Well, I just checked prices for the 1503 & 1507 and I'm pleasantly
surprised. The 1503 ranges from about $291-$370. Here's the place I found it
for $291 <http://www.testequipmentdepot.com/fluke/megohmmeters/1503.htm>
http://www.testequipmentdepot.com/fluke/megohmmeters/1503.htm That's marked
down from the regular price of $342.



The 1507 ranges from about $385 to $500. Here's where I found it for $385...
<http://www.testequipmentdepot.com/fluke/megohmmeters/1507.htm>
http://www.testequipmentdepot.com/fluke/megohmmeters/1507.htm That's a
special price, for you only, down from $454.



All things considered if I were in your shoes, I'd go for the 1503. That
give you a solid megger that you can dedicate to that purpose for a
reasonale muggering. If it were me, in Matt's shoes... Oh, what am I saying?
I've already got mine and I just found out I paid too much for it! But I
have Battery Check... Neener neener neener!



Be safe out there!



Matt Lafferty



I hope more hands go up on this topic. Thanks for asking, Keith.



Peace and Palm Trees everybody,



Matt Lafferty



-------------- next part --------------
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URL: <http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org/attachments/20090428/69631bff/attachment.htm>
Joel Davidson
2009-04-29 01:34:50 UTC
Permalink
Hello Matt,
All UL modules or panels with accessible metal parts are rquired to be production line factory dielectric voltage-withstand tested for 1 minute without electrical breakdown at 2 times maximum system dc voltage plus 1,000 volts (UL 1703, Section 43).
Joel Davidson
----- Original Message -----
From: Matt Lafferty
To: 'RE-wrenches'
Sent: Tuesday, April 28, 2009 12:48 PM
Subject: Re: [RE-wrenches] To Megger or not to Megger


Hi Bill,

I so totally agree with your comment about the price of these being a non-issue, all things considered. As long as we're getting the features we need in the sub-$750 range, that is. When it comes down to it, this is meaningful safety and reliability stuff. No slam to the Bolinas crew, but the SunEye is a lettle less important than that. Unless, of course, you shade a certain type of module and the bypass diode fails and the thing ignites.... Then you could make a case for the SunEye being prudent for Disqualification of location, which would mean there wouldn't be a need for the megger on that non-job.

Perhaps you could address a couple of aspects that I have questioned for a long time.

First of all, is it or is it not true that megger testing an array at 1kV may result in flaky-bias diodes (my term) if polarity of test leads is incorrect relative the array and/or the array wiring is grounded/not grounded during the test? (The root of my policy to NOT megger arrays unless I have specific procedure provided by the mfr... Me no wanna get in a "you meggered it so you don't have a warranty" conversation if ya know of what I speak.)

Which of the mainstream module manufacturers are publishing a procedure for megger testing their arrays for use by installers?

Are these being published for wet or dry testing? Both?

Which of these manufacturers are supplying this documentation in a publicly accessible manner? (Asked quite a few sales reps over the years and only 1 ever produced a document... I have been able to get some from engineers in the factory, but this was generally when I had a big stick to pound on somebody's desk.)

Why don't most installers and distributors know this documentation exists or understand the procedure at this point?

Yeah, it's one of those thorny issues with me. Maybe we can get our heads together to steamroll a solution to the above. Happy to take the subject up off-list if you like.

On to today's question regarding resolution....

When you are measuring an array, why is the resolution so critical?
What value or value range do you believe constitutes a Pass on a quality Csi product?
How about Asi / CdTe with crappy glass?
How about Asi with Tefcel?
Wet? Dry?
Does your answer change relative the capacity of the array portion under test?
Does the answer change with temperature &/or relative humidity?
Does the answer change relative test voltage compared to array VOC?

What I'm getting at is, unless the minimum "Pass" value is a very low number for the test setup, say 200K - 2M, or has a very narrow "Pass" range, a super-fine resolution shouldn't be that critical. On the few occasions back in the day when I actually meggered arrays, I used an analog megger. Top end range @ 1kV was 250M. My recollection is that these things pulled 15M or better, but I can't really testify to that... Fuzzy memory on the actual values. I'd have to dig through some deep stacks of paperwork to find out if I have any archives of the tests, and I'm not gonna do that for this post. Had to submit the test results to SMUD (can't find them) and the mfrs. Nobody ever said, "Hey. Close your other eye and tell me what it says." When I asked what values would be appropriate, all I ever got was, "Just like you got here. These are good." Never could nail them down and, frankly, never got the idea that they were all-to-happy having installers owning meggers.

I'm with you on testing the array and module interconnects for leakage. Really. But, if the arrays rings out as "faulted" when it's really "OK", why bother? What are you looking for? If the resistance is that low, maybe we should be using a "Kohmer" for the arrays and a Megger for the wiring & equpment bussing. If you're getting such a low resistance, aren't you picking it up with a "Static" test... Would the Earth Bond Resistance function of the 1507 & 1503 be sufficient for these situations? http://us.fluke.com/usen/products/specifications.htm?cs_id=35391(FlukeProducts)&category=HMA(FlukeProducts) This is basically a voltage shot like a megger, but measures resistance in the <20k range. Resolution very nice there! This tester has a gap between 20k & 100k (0.1M).

From a "reasonable resolution" perspective, I think the gap is more like 20k to 2M. Anything over 2M, the 0.1M resolution should be fine. If the array is that close to failing, fail it and tell the mfr to start making some decent glass. They might understand it better this way: ??

Dunno. I think it comes down to figuring out what ranges equal "Pass" for the application and going from there. Will look forward to what you find in your side-by-sides later this week. Please do post back. With a basic description of the glass-type, mounting, wire-management, test results and findings, if you can.

I'm gonna hang onto my 1520... If anybody wants to see what one looks like with a 100% Battery Level, let me know... I'll hold it up in front of my webcam for ya!

No Ground Faults!

Matt Lafferty

-------------- next part --------------
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Joel Davidson
2009-04-29 01:34:50 UTC
Permalink
Hello Matt,
All UL modules or panels with accessible metal parts are rquired to be production line factory dielectric voltage-withstand tested for 1 minute without electrical breakdown at 2 times maximum system dc voltage plus 1,000 volts (UL 1703, Section 43).
Joel Davidson
----- Original Message -----
From: Matt Lafferty
To: 'RE-wrenches'
Sent: Tuesday, April 28, 2009 12:48 PM
Subject: Re: [RE-wrenches] To Megger or not to Megger


Hi Bill,

I so totally agree with your comment about the price of these being a non-issue, all things considered. As long as we're getting the features we need in the sub-$750 range, that is. When it comes down to it, this is meaningful safety and reliability stuff. No slam to the Bolinas crew, but the SunEye is a lettle less important than that. Unless, of course, you shade a certain type of module and the bypass diode fails and the thing ignites.... Then you could make a case for the SunEye being prudent for Disqualification of location, which would mean there wouldn't be a need for the megger on that non-job.

Perhaps you could address a couple of aspects that I have questioned for a long time.

First of all, is it or is it not true that megger testing an array at 1kV may result in flaky-bias diodes (my term) if polarity of test leads is incorrect relative the array and/or the array wiring is grounded/not grounded during the test? (The root of my policy to NOT megger arrays unless I have specific procedure provided by the mfr... Me no wanna get in a "you meggered it so you don't have a warranty" conversation if ya know of what I speak.)

Which of the mainstream module manufacturers are publishing a procedure for megger testing their arrays for use by installers?

Are these being published for wet or dry testing? Both?

Which of these manufacturers are supplying this documentation in a publicly accessible manner? (Asked quite a few sales reps over the years and only 1 ever produced a document... I have been able to get some from engineers in the factory, but this was generally when I had a big stick to pound on somebody's desk.)

Why don't most installers and distributors know this documentation exists or understand the procedure at this point?

Yeah, it's one of those thorny issues with me. Maybe we can get our heads together to steamroll a solution to the above. Happy to take the subject up off-list if you like.

On to today's question regarding resolution....

When you are measuring an array, why is the resolution so critical?
What value or value range do you believe constitutes a Pass on a quality Csi product?
How about Asi / CdTe with crappy glass?
How about Asi with Tefcel?
Wet? Dry?
Does your answer change relative the capacity of the array portion under test?
Does the answer change with temperature &/or relative humidity?
Does the answer change relative test voltage compared to array VOC?

What I'm getting at is, unless the minimum "Pass" value is a very low number for the test setup, say 200K - 2M, or has a very narrow "Pass" range, a super-fine resolution shouldn't be that critical. On the few occasions back in the day when I actually meggered arrays, I used an analog megger. Top end range @ 1kV was 250M. My recollection is that these things pulled 15M or better, but I can't really testify to that... Fuzzy memory on the actual values. I'd have to dig through some deep stacks of paperwork to find out if I have any archives of the tests, and I'm not gonna do that for this post. Had to submit the test results to SMUD (can't find them) and the mfrs. Nobody ever said, "Hey. Close your other eye and tell me what it says." When I asked what values would be appropriate, all I ever got was, "Just like you got here. These are good." Never could nail them down and, frankly, never got the idea that they were all-to-happy having installers owning meggers.

I'm with you on testing the array and module interconnects for leakage. Really. But, if the arrays rings out as "faulted" when it's really "OK", why bother? What are you looking for? If the resistance is that low, maybe we should be using a "Kohmer" for the arrays and a Megger for the wiring & equpment bussing. If you're getting such a low resistance, aren't you picking it up with a "Static" test... Would the Earth Bond Resistance function of the 1507 & 1503 be sufficient for these situations? http://us.fluke.com/usen/products/specifications.htm?cs_id=35391(FlukeProducts)&category=HMA(FlukeProducts) This is basically a voltage shot like a megger, but measures resistance in the <20k range. Resolution very nice there! This tester has a gap between 20k & 100k (0.1M).

From a "reasonable resolution" perspective, I think the gap is more like 20k to 2M. Anything over 2M, the 0.1M resolution should be fine. If the array is that close to failing, fail it and tell the mfr to start making some decent glass. They might understand it better this way: ??

Dunno. I think it comes down to figuring out what ranges equal "Pass" for the application and going from there. Will look forward to what you find in your side-by-sides later this week. Please do post back. With a basic description of the glass-type, mounting, wire-management, test results and findings, if you can.

I'm gonna hang onto my 1520... If anybody wants to see what one looks like with a 100% Battery Level, let me know... I'll hold it up in front of my webcam for ya!

No Ground Faults!

Matt Lafferty

-------------- next part --------------
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Matt Lafferty
2009-04-28 19:48:59 UTC
Permalink
Hi Bill,

I so totally agree with your comment about the price of these being a
non-issue, all things considered. As long as we're getting the features we
need in the sub-$750 range, that is. When it comes down to it, this is
meaningful safety and reliability stuff. No slam to the Bolinas crew, but
the SunEye is a lettle less important than that. Unless, of course, you
shade a certain type of module and the bypass diode fails and the thing
ignites.... Then you could make a case for the SunEye being prudent for
Disqualification of location, which would mean there wouldn't be a need for
the megger on that non-job.

Perhaps you could address a couple of aspects that I have questioned for a
long time.

First of all, is it or is it not true that megger testing an array at 1kV
may result in flaky-bias diodes (my term) if polarity of test leads is
incorrect relative the array and/or the array wiring is grounded/not
grounded during the test? (The root of my policy to NOT megger arrays unless
I have specific procedure provided by the mfr... Me no wanna get in a "you
meggered it so you don't have a warranty" conversation if ya know of what I
speak.)

Which of the mainstream module manufacturers are publishing a procedure for
megger testing their arrays for use by installers?

Are these being published for wet or dry testing? Both?

Which of these manufacturers are supplying this documentation in a publicly
accessible manner? (Asked quite a few sales reps over the years and only 1
ever produced a document... I have been able to get some from engineers in
the factory, but this was generally when I had a big stick to pound on
somebody's desk.)

Why don't most installers and distributors know this documentation exists or
understand the procedure at this point?

Yeah, it's one of those thorny issues with me. Maybe we can get our heads
together to steamroll a solution to the above. Happy to take the subject up
off-list if you like.

On to today's question regarding resolution....

When you are measuring an array, why is the resolution so critical?
What value or value range do you believe constitutes a Pass on a quality Csi
product?
How about Asi / CdTe with crappy glass?
How about Asi with Tefcel?
Wet? Dry?
Does your answer change relative the capacity of the array portion under
test?
Does the answer change with temperature &/or relative humidity?
Does the answer change relative test voltage compared to array VOC?

What I'm getting at is, unless the minimum "Pass" value is a very low number
for the test setup, say 200K - 2M, or has a very narrow "Pass" range, a
super-fine resolution shouldn't be that critical. On the few occasions back
in the day when I actually meggered arrays, I used an analog megger. Top end
range @ 1kV was 250M. My recollection is that these things pulled 15M or
better, but I can't really testify to that... Fuzzy memory on the actual
values. I'd have to dig through some deep stacks of paperwork to find out if
I have any archives of the tests, and I'm not gonna do that for this post.
Had to submit the test results to SMUD (can't find them) and the mfrs.
Nobody ever said, "Hey. Close your other eye and tell me what it says." When
I asked what values would be appropriate, all I ever got was, "Just like you
got here. These are good." Never could nail them down and, frankly, never
got the idea that they were all-to-happy having installers owning meggers.

I'm with you on testing the array and module interconnects for leakage.
Really. But, if the arrays rings out as "faulted" when it's really "OK", why
bother? What are you looking for? If the resistance is that low, maybe we
should be using a "Kohmer" for the arrays and a Megger for the wiring &
equpment bussing. If you're getting such a low resistance, aren't you
picking it up with a "Static" test... Would the Earth Bond Resistance
function of the 1507 & 1503 be sufficient for these situations?
http://us.fluke.com/usen/products/specifications.htm?cs_id=35391(FlukeProduc
ts)
<http://us.fluke.com/usen/products/specifications.htm?cs_id=35391(FlukeProdu
cts)&category=HMA(FlukeProducts> &category=HMA(FlukeProducts) This is
basically a voltage shot like a megger, but measures resistance in the <20k
range. Resolution very nice there! This tester has a gap between 20k & 100k
(0.1M).

>From a "reasonable resolution" perspective, I think the gap is more like 20k
to 2M. Anything over 2M, the 0.1M resolution should be fine. If the array is
that close to failing, fail it and tell the mfr to start making some decent
glass. They might understand it better this way: ??

Dunno. I think it comes down to figuring out what ranges equal "Pass" for
the application and going from there. Will look forward to what you find in
your side-by-sides later this week. Please do post back. With a basic
description of the glass-type, mounting, wire-management, test results and
findings, if you can.

I'm gonna hang onto my 1520... If anybody wants to see what one looks like
with a 100% Battery Level, let me know... I'll hold it up in front of my
webcam for ya!

No Ground Faults!

Matt Lafferty

_____

From: re-wrenches-bounces at lists.re-wrenches.org
[mailto:re-wrenches-bounces at lists.re-wrenches.org] On Behalf Of Bill Brooks
Sent: Tuesday, April 28, 2009 10:40 AM
To: 'RE-wrenches'
Subject: Re: [RE-wrenches] To Megger or not to Megger



Dave,



The issue is definitely resolution. The cool thing about the Fluke 1520 is
that it goes down to 0.001MOhms (1000 Ohms). That is the resolution you are
looking for. Neither of the current Flukes go low enough. That is why I?m
going into the field later this week to see how a 0.1MOhm meter stacks up to
finding faults?I have an array with a pesky fault that should make it fun.



Many arrays will ring out as a faulted array when, in fact, everything is
fine. This is especially true of a-Si arrays with low quality glass. They
are very leaky. I?ll keep looking and report back on a recommendation for
Christmas shopping.



Just to add punctuation to this thread, I always recommend that contractors
megger their arrays, because it has saved my butt several times. Also, with
exterior wiring systems it is even more important. The problem in the early
days is that people would whine about the $600-$1000 price tag. In my
opinion, that argument is gone. With contractors routinely putting down
$1400 for a SunEye, the value of a good megger is similar and costs less.



Bill.



From: re-wrenches-bounces at lists.re-wrenches.org
[mailto:re-wrenches-bounces at lists.re-wrenches.org] On Behalf Of David
Palumbo
Sent: Tuesday, April 28, 2009 7:59 AM
To: gilligan06 at gmail.com; 'RE-wrenches'
Subject: Re: [RE-wrenches] To Megger or not to Megger



Matt,



?Muggering?, I think that will catch on. The last post, I think, ol?
Uncle Bill Brooks (4/13/09 8:17 PM) had on this topic raised a concern about
?not having enough resolution in the low impedance area. PV arrays can have
an impedance to ground of a slow as 2kOhms. A resolution of 0.1MOhms will
likely not cut it.? Bill went on to say that he had bought a cheaper meter
to test out ?for fun?. Some of us do enjoy ?muggering around?.



So my question is. Do the Fluke 1503?s and 1507?s have enough resolution
in the low range?



Dave



From: re-wrenches-bounces at lists.re-wrenches.org
[mailto:re-wrenches-bounces at lists.re-wrenches.org] On Behalf Of Matt
Lafferty
Sent: Tuesday, April 28, 2009 9:56 AM
To: 'RE-wrenches'
Subject: Re: [RE-wrenches] To Megger or not to Megger



RE: Suggested replacements for Fluke 1520 and "pricey meters"... Good News
below!



Another Wrench sent me a note off-list last night, asking how much a
"muggering" would cost. Here's what I sent him:



When I got that 1520 it was just over $600. I just checked online and find
that it's a discontinued item... Bummer!



Fluke recommends the 1587 or the 1507 or the 1503. They also mention the
1577, but it's an ugly stepsister, or maybe a retarded adopted relative, to
the 1587.



The 1587 is basically a multimeter that also has a <TEST> button to
discharge a high voltage shock into the sample under test... It runs about
$620 from standard distributors.
<http://us.fluke.com/usen/products/Fluke+1587+1577.htm?catalog_name=FlukeUni
tedStates>
http://us.fluke.com/usen/products/Fluke+1587+1577.htm?catalog_name=FlukeUnit
edStates You can get it for $522 here:

<http://www.testequipmentdepot.com/fluke/megohmmeters/1577_87.htm>
http://www.testequipmentdepot.com/fluke/megohmmeters/1577_87.htm NOTE: It
does not test at 10A in DMM mode which means it wouldn't be able to test
short-circuit current in strings. Don't bother with the 1577!



The 1507 & 1503 are more robust equipment. You can check them out here:
<http://us.fluke.com/usen/products/features.htm?cs_id=35391(FlukeProducts)&c
ategory=HMA(FlukeProducts>
http://us.fluke.com/usen/products/features.htm?cs_id=35391(FlukeProducts)&ca
tegory=HMA(FlukeProducts) While they do measure AC & DC Voltages to 600V as
well as some lower ohm & continuity work, they are really more tailored to
being a megger. The 1503 will suffice for most of what I expect you will get
into, but there are some features on the 1507 that might make it worth
considering. Mind you, I haven't looked at at price on either yet, so that
last comment may just be noises coming out my ass.



The 1507 has a Compare function which basically sets up a Pass/Fail value so
you can quickly run through repeated tests. This would be useful for doing
larger systems where you are testing dozens or hundreds of circuits at a
time. For my purposes, I want my guys to think a little more than "Buzz =
OK" and I want them to write an actual tested value down on a piece of paper
so this is not a big plus to me.



The 1507 also does Polarization Index and Absorption Ratios. These are more
advanced di-electric tests that you are not likely to need in smaller scale
PV. Use of these features would come into play when playing with real
high-voltage gear or transformers. Might also come into play on
super-sensitive equipment. They might also be used to assess older or aging
underground or overhead feeders.



The 1507 & 1503 both have an Earth Bond Resistance function which is likely
to become more of an issue in the future. This feature lets you test the
resistance between a grounding electrode or a grounding electrode conductor
and actual earth. Another use for this feature would be to set the output to
1kV, connect the alligator jaw to one of <Insert name of your
least-favorite building official here> extremities and use the probe lead as
a tongue depressor while you push <TEST>. This feature used to be in a
single-purpose tester that ran >$2K. They also both have backlit displays
which comes in real handy out in the field.



The primary features you want are: 500V & 1kV Test Voltage and 2 Gohms
(2,000 Megaohms) or above for the top end of the range. Any of the 3 meet
this spec.



Well, I just checked prices for the 1503 & 1507 and I'm pleasantly
surprised. The 1503 ranges from about $291-$370. Here's the place I found it
for $291 <http://www.testequipmentdepot.com/fluke/megohmmeters/1503.htm>
http://www.testequipmentdepot.com/fluke/megohmmeters/1503.htm That's marked
down from the regular price of $342.



The 1507 ranges from about $385 to $500. Here's where I found it for $385...
<http://www.testequipmentdepot.com/fluke/megohmmeters/1507.htm>
http://www.testequipmentdepot.com/fluke/megohmmeters/1507.htm That's a
special price, for you only, down from $454.



All things considered if I were in your shoes, I'd go for the 1503. That
give you a solid megger that you can dedicate to that purpose for a
reasonale muggering. If it were me, in Matt's shoes... Oh, what am I saying?
I've already got mine and I just found out I paid too much for it! But I
have Battery Check... Neener neener neener!



Be safe out there!



Matt Lafferty



I hope more hands go up on this topic. Thanks for asking, Keith.



Peace and Palm Trees everybody,



Matt Lafferty



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Bill Brooks
2009-04-28 17:39:44 UTC
Permalink
Dave,



The issue is definitely resolution. The cool thing about the Fluke 1520 is
that it goes down to 0.001MOhms (1000 Ohms). That is the resolution you are
looking for. Neither of the current Flukes go low enough. That is why I'm
going into the field later this week to see how a 0.1MOhm meter stacks up to
finding faults-I have an array with a pesky fault that should make it fun.



Many arrays will ring out as a faulted array when, in fact, everything is
fine. This is especially true of a-Si arrays with low quality glass. They
are very leaky. I'll keep looking and report back on a recommendation for
Christmas shopping.



Just to add punctuation to this thread, I always recommend that contractors
megger their arrays, because it has saved my butt several times. Also, with
exterior wiring systems it is even more important. The problem in the early
days is that people would whine about the $600-$1000 price tag. In my
opinion, that argument is gone. With contractors routinely putting down
$1400 for a SunEye, the value of a good megger is similar and costs less.



Bill.



From: re-wrenches-bounces at lists.re-wrenches.org
[mailto:re-wrenches-bounces at lists.re-wrenches.org] On Behalf Of David
Palumbo
Sent: Tuesday, April 28, 2009 7:59 AM
To: gilligan06 at gmail.com; 'RE-wrenches'
Subject: Re: [RE-wrenches] To Megger or not to Megger



Matt,



"Muggering", I think that will catch on. The last post, I think, ol' Uncle
Bill Brooks (4/13/09 8:17 PM) had on this topic raised a concern about "not
having enough resolution in the low impedance area. PV arrays can have an
impedance to ground of a slow as 2kOhms. A resolution of 0.1MOhms will
likely not cut it." Bill went on to say that he had bought a cheaper meter
to test out "for fun". Some of us do enjoy "muggering around".



So my question is. Do the Fluke 1503's and 1507's have enough resolution
in the low range?



Dave



From: re-wrenches-bounces at lists.re-wrenches.org
[mailto:re-wrenches-bounces at lists.re-wrenches.org] On Behalf Of Matt
Lafferty
Sent: Tuesday, April 28, 2009 9:56 AM
To: 'RE-wrenches'
Subject: Re: [RE-wrenches] To Megger or not to Megger



RE: Suggested replacements for Fluke 1520 and "pricey meters"... Good News
below!



Another Wrench sent me a note off-list last night, asking how much a
"muggering" would cost. Here's what I sent him:



When I got that 1520 it was just over $600. I just checked online and find
that it's a discontinued item... Bummer!



Fluke recommends the 1587 or the 1507 or the 1503. They also mention the
1577, but it's an ugly stepsister, or maybe a retarded adopted relative, to
the 1587.



The 1587 is basically a multimeter that also has a <TEST> button to
discharge a high voltage shock into the sample under test... It runs about
$620 from standard distributors.
<http://us.fluke.com/usen/products/Fluke+1587+1577.htm?catalog_name=FlukeUni
tedStates>
http://us.fluke.com/usen/products/Fluke+1587+1577.htm?catalog_name=FlukeUnit
edStates You can get it for $522 here:

<http://www.testequipmentdepot.com/fluke/megohmmeters/1577_87.htm>
http://www.testequipmentdepot.com/fluke/megohmmeters/1577_87.htm NOTE: It
does not test at 10A in DMM mode which means it wouldn't be able to test
short-circuit current in strings. Don't bother with the 1577!



The 1507 & 1503 are more robust equipment. You can check them out here:
<http://us.fluke.com/usen/products/features.htm?cs_id=35391(FlukeProducts)&c
ategory=HMA(FlukeProducts>
http://us.fluke.com/usen/products/features.htm?cs_id=35391(FlukeProducts)&ca
tegory=HMA(FlukeProducts) While they do measure AC & DC Voltages to 600V as
well as some lower ohm & continuity work, they are really more tailored to
being a megger. The 1503 will suffice for most of what I expect you will get
into, but there are some features on the 1507 that might make it worth
considering. Mind you, I haven't looked at at price on either yet, so that
last comment may just be noises coming out my ass.



The 1507 has a Compare function which basically sets up a Pass/Fail value so
you can quickly run through repeated tests. This would be useful for doing
larger systems where you are testing dozens or hundreds of circuits at a
time. For my purposes, I want my guys to think a little more than "Buzz =
OK" and I want them to write an actual tested value down on a piece of paper
so this is not a big plus to me.



The 1507 also does Polarization Index and Absorption Ratios. These are more
advanced di-electric tests that you are not likely to need in smaller scale
PV. Use of these features would come into play when playing with real
high-voltage gear or transformers. Might also come into play on
super-sensitive equipment. They might also be used to assess older or aging
underground or overhead feeders.



The 1507 & 1503 both have an Earth Bond Resistance function which is likely
to become more of an issue in the future. This feature lets you test the
resistance between a grounding electrode or a grounding electrode conductor
and actual earth. Another use for this feature would be to set the output to
1kV, connect the alligator jaw to one of Mike Gripando's extremities and use
the probe lead as a tongue depressor while you push <TEST>. This feature
used to be in a single-purpose tester that ran >$2K. They also both have
backlit displays which comes in real handy out in the field.



The primary features you want are: 500V & 1kV Test Voltage and 2 Gohms
(2,000 Megaohms) or above for the top end of the range. Any of the 3 meet
this spec.



Well, I just checked prices for the 1503 & 1507 and I'm pleasantly
surprised. The 1503 ranges from about $291-$370. Here's the place I found it
for $291 <http://www.testequipmentdepot.com/fluke/megohmmeters/1503.htm>
http://www.testequipmentdepot.com/fluke/megohmmeters/1503.htm That's marked
down from the regular price of $342.



The 1507 ranges from about $385 to $500. Here's where I found it for $385...
<http://www.testequipmentdepot.com/fluke/megohmmeters/1507.htm>
http://www.testequipmentdepot.com/fluke/megohmmeters/1507.htm That's a
special price, for you only, down from $454.



All things considered if I were in your shoes, I'd go for the 1503. That
give you a solid megger that you can dedicate to that purpose for a
reasonale muggering. If it were me, in Matt's shoes... Oh, what am I saying?
I've already got mine and I just found out I paid too much for it! But I
have Battery Check... Neener neener neener!



Be safe out there!



Matt Lafferty



I hope more hands go up on this topic. Thanks for asking, Keith.



Peace and Palm Trees everybody,



Matt Lafferty



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robert ellison
2009-04-28 14:11:55 UTC
Permalink
http://www.testequipmentdepot.com/fluke/pricelist.htm Has a 1507 for $385.06




On Tue, Apr 28, 2009 at 9:55 AM, Matt Lafferty <gilligan06 at gmail.com> wrote:

> RE: Suggested replacements for Fluke 1520 and "pricey meters"... Good
> News below!
>
> Another Wrench sent me a note off-list last night, asking how much a
> "muggering" would cost. Here's what I sent him:
>
> When I got that 1520 it was just over $600. I just checked online and find
> that it's a discontinued item... Bummer!
>
> Fluke recommends the 1587 or the 1507 or the 1503. They also mention the
> 1577, but it's an ugly stepsister, or maybe a retarded adopted relative, to
> the 1587.
>
> The 1587 is basically a multimeter that also has a <TEST> button to
> discharge a high voltage shock into the sample under test... It runs about
> $620 from standard distributors.
> http://us.fluke.com/usen/products/Fluke+1587+1577.htm?catalog_name=FlukeUnitedStates
> You can get it for $522 here:
> http://www.testequipmentdepot.com/fluke/megohmmeters/1577_87.htm NOTE: It
> does not test at 10A in DMM mode which means it wouldn't be able to test
> short-circuit current in strings. Don't bother with the 1577!
>
> The 1507 & 1503 are more robust equipment. You can check them out here:
> http://us.fluke.com/usen/products/features.htm?cs_id=35391(FlukeProducts)&category=HMA(FlukeProducts)
> While they do measure AC & DC Voltages to 600V as well as some lower ohm &
> continuity work, they are really more tailored to being a megger. The 1503
> will suffice for most of what I expect you will get into, but there are some
> features on the 1507 that might make it worth considering. Mind you, I
> haven't looked at at price on either yet, so that last comment may just be
> noises coming out my ass.
>
> The 1507 has a Compare function which basically sets up a Pass/Fail value
> so you can quickly run through repeated tests. This would be useful for
> doing larger systems where you are testing dozens or hundreds of circuits at
> a time. For my purposes, I want my guys to think a little more than "Buzz =
> OK" and I want them to write an actual tested value down on a piece of paper
> so this is not a big plus to me.
>
> The 1507 also does Polarization Index and Absorption Ratios. These are more
> advanced di-electric tests that you are not likely to need in smaller scale
> PV. Use of these features would come into play when playing with real
> high-voltage gear or transformers. Might also come into play on
> super-sensitive equipment. They might also be used to assess older or aging
> underground or overhead feeders.
>
> The 1507 & 1503 both have an Earth Bond Resistance function which is likely
> to become more of an issue in the future. This feature lets you test the
> resistance between a grounding electrode or a grounding electrode conductor
> and actual earth. Another use for this feature would be to set the output to
> 1kV, connect the alligator jaw to one of Mike Gripando's extremities and use
> the probe lead as a tongue depressor while you push <TEST>. This feature
> used to be in a single-purpose tester that ran >$2K. They also both have
> backlit displays which comes in real handy out in the field.
>
> The primary features you want are: 500V & 1kV Test Voltage and 2 Gohms
> (2,000 Megaohms) or above for the top end of the range. Any of the 3 meet
> this spec.
>
> Well, I just checked prices for the 1503 & 1507 and I'm pleasantly
> surprised. The 1503 ranges from about $291-$370. Here's the place I found
> it for *$291 *
> http://www.testequipmentdepot.com/fluke/megohmmeters/1503.htm That's
> marked down from the regular price of $342.
>
> The 1507 ranges from about $385 to $500. Here's where I found it for *$385...
> *http://www.testequipmentdepot.com/fluke/megohmmeters/1507.htm That's a
> special price, for you only, down from $454.
>
> All things considered if I were in your shoes, I'd go for the 1503. That
> give you a solid megger that you can dedicate to that purpose for a
> reasonale muggering. If it were me, in Matt's shoes... Oh, what am I
> saying? I've already got mine and I just found out I paid too much for it!
> But I have Battery Check... Neener neener neener!
>
> Be safe out there!
>
> Matt Lafferty
>
>
>> I hope more hands go up on this topic. Thanks for asking, Keith.
>>
>> Peace and Palm Trees everybody,
>>
>> Matt Lafferty
>>
>
>
> _______________________________________________
> List sponsored by Home Power magazine
>
> List Address: RE-wrenches at lists.re-wrenches.org
>
> Options & settings:
> http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org
>
> List-Archive:
> http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org
>
> List rules & etiquette:
> www.re-wrenches.org/etiquette.htm
>
> Check out participant bios:
> www.members.re-wrenches.org
>
>
>
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David Palumbo
2009-04-28 14:59:20 UTC
Permalink
Matt,



"Muggering", I think that will catch on. The last post, I think, ol' Uncle
Bill Brooks (4/13/09 8:17 PM) had on this topic raised a concern about "not
having enough resolution in the low impedance area. PV arrays can have an
impedance to ground of a slow as 2kOhms. A resolution of 0.1MOhms will
likely not cut it." Bill went on to say that he had bought a cheaper meter
to test out "for fun". Some of us do enjoy "muggering around".



So my question is. Do the Fluke 1503's and 1507's have enough resolution
in the low range?



Dave



From: re-wrenches-bounces at lists.re-wrenches.org
[mailto:re-wrenches-bounces at lists.re-wrenches.org] On Behalf Of Matt
Lafferty
Sent: Tuesday, April 28, 2009 9:56 AM
To: 'RE-wrenches'
Subject: Re: [RE-wrenches] To Megger or not to Megger



RE: Suggested replacements for Fluke 1520 and "pricey meters"... Good News
below!



Another Wrench sent me a note off-list last night, asking how much a
"muggering" would cost. Here's what I sent him:



When I got that 1520 it was just over $600. I just checked online and find
that it's a discontinued item... Bummer!



Fluke recommends the 1587 or the 1507 or the 1503. They also mention the
1577, but it's an ugly stepsister, or maybe a retarded adopted relative, to
the 1587.



The 1587 is basically a multimeter that also has a <TEST> button to
discharge a high voltage shock into the sample under test... It runs about
$620 from standard distributors.
<http://us.fluke.com/usen/products/Fluke+1587+1577.htm?catalog_name=FlukeUni
tedStates>
http://us.fluke.com/usen/products/Fluke+1587+1577.htm?catalog_name=FlukeUnit
edStates You can get it for $522 here:

<http://www.testequipmentdepot.com/fluke/megohmmeters/1577_87.htm>
http://www.testequipmentdepot.com/fluke/megohmmeters/1577_87.htm NOTE: It
does not test at 10A in DMM mode which means it wouldn't be able to test
short-circuit current in strings. Don't bother with the 1577!



The 1507 & 1503 are more robust equipment. You can check them out here:
<http://us.fluke.com/usen/products/features.htm?cs_id=35391(FlukeProducts)&c
ategory=HMA(FlukeProducts>
http://us.fluke.com/usen/products/features.htm?cs_id=35391(FlukeProducts)&ca
tegory=HMA(FlukeProducts) While they do measure AC & DC Voltages to 600V as
well as some lower ohm & continuity work, they are really more tailored to
being a megger. The 1503 will suffice for most of what I expect you will get
into, but there are some features on the 1507 that might make it worth
considering. Mind you, I haven't looked at at price on either yet, so that
last comment may just be noises coming out my ass.



The 1507 has a Compare function which basically sets up a Pass/Fail value so
you can quickly run through repeated tests. This would be useful for doing
larger systems where you are testing dozens or hundreds of circuits at a
time. For my purposes, I want my guys to think a little more than "Buzz =
OK" and I want them to write an actual tested value down on a piece of paper
so this is not a big plus to me.



The 1507 also does Polarization Index and Absorption Ratios. These are more
advanced di-electric tests that you are not likely to need in smaller scale
PV. Use of these features would come into play when playing with real
high-voltage gear or transformers. Might also come into play on
super-sensitive equipment. They might also be used to assess older or aging
underground or overhead feeders.



The 1507 & 1503 both have an Earth Bond Resistance function which is likely
to become more of an issue in the future. This feature lets you test the
resistance between a grounding electrode or a grounding electrode conductor
and actual earth. Another use for this feature would be to set the output to
1kV, connect the alligator jaw to one of Mike Gripando's extremities and use
the probe lead as a tongue depressor while you push <TEST>. This feature
used to be in a single-purpose tester that ran >$2K. They also both have
backlit displays which comes in real handy out in the field.



The primary features you want are: 500V & 1kV Test Voltage and 2 Gohms
(2,000 Megaohms) or above for the top end of the range. Any of the 3 meet
this spec.



Well, I just checked prices for the 1503 & 1507 and I'm pleasantly
surprised. The 1503 ranges from about $291-$370. Here's the place I found it
for $291 <http://www.testequipmentdepot.com/fluke/megohmmeters/1503.htm>
http://www.testequipmentdepot.com/fluke/megohmmeters/1503.htm That's marked
down from the regular price of $342.



The 1507 ranges from about $385 to $500. Here's where I found it for $385...
<http://www.testequipmentdepot.com/fluke/megohmmeters/1507.htm>
http://www.testequipmentdepot.com/fluke/megohmmeters/1507.htm That's a
special price, for you only, down from $454.



All things considered if I were in your shoes, I'd go for the 1503. That
give you a solid megger that you can dedicate to that purpose for a
reasonale muggering. If it were me, in Matt's shoes... Oh, what am I saying?
I've already got mine and I just found out I paid too much for it! But I
have Battery Check... Neener neener neener!



Be safe out there!



Matt Lafferty



I hope more hands go up on this topic. Thanks for asking, Keith.



Peace and Palm Trees everybody,



Matt Lafferty



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David Palumbo
2009-04-28 12:33:16 UTC
Permalink
What are the options to the Fluke 1520? Also what are good sources for
purchasing these pricey meters?



Dave



From: re-wrenches-bounces at lists.re-wrenches.org
[mailto:re-wrenches-bounces at lists.re-wrenches.org] On Behalf Of robert
ellison
Sent: Tuesday, April 28, 2009 6:24 AM
To: RE-wrenches
Subject: Re: [RE-wrenches] To Megger or not to Megger



Just went to check the Fluke 1520 price. Looks like it is discontinued.

They do have a couple suggested replacements.



Just for reference,

Bob

On Mon, Apr 27, 2009 at 11:08 PM, Matt Lafferty <gilligan06 at gmail.com>
wrote:

Hi Keith,



Both hands up here. From day 1 in PV.



Every single field-installed current carrying conductor to the point of
termination. AC & DC. BEFORE energizing them! One megger lead on the
conductor, the other on the raceway or ground-wire. Megger @ 1kV. Must be
greater than 250 Megohms to pass. Record the values on your commissioning
sheet.



I only meggered the actual arrays on projects where it was a requirement and
I only did that following specific procedures provided by the module
manufacturer. No procedure from the mfr = No array megger.



I believe it's a critical thing to do as part of the commissioning. But then
again, I don't like ground faults or fires.



I'll never forget a couple of head scratchers that the megger found.... One
was a perfectly fine, 6' long piece of Orange #12 XHHW-2 that would only
pull 40 Megohms installed in EMT. Pulled it out and replaced it. Inspected
it for any visible flaws. None found. Not a scratch or scuff. Used it as a
training tool for my guys. Hung it on the wall over my desk as a handy
reminder. If anybody wants a picture...



The other was interesting, too. The very first PV system I ever installed.
Was shooting the DC circuits from the inverter all the way to the connector
on the output jumper cables at the modules. Megger showed dead short on one
wire. Fluke 79 on ohms showed clear. Hit it with the megger again. Dead
short. I'm known for being anal about conduit and wire installation, so this
was quite unexpected, not to mention a little embarrassing. This happened to
be a Solarex Millennia Integra system with an Omnion inverter and the array
happened to be scattered all over this roof. For those of you who who have
dealt with that situation, you'll understand what a cluster-*$#! that is...
Especially being my very first PV system and all... I wasn't anywhere near
confident that I had a clue by that point. All ready to see my first install
fire up and this happens.



It was my first install and I had 3 people getting paid prevailing wages to
learn... I was learning too, but I wasn't making anywhere near prevailing
wages, let me tell ya. Well, it was early January, late in the day and foggy
as foggy gets, but we went back onto the roof anyway. Yeah... Overtime for
everybody but me. We opened up the condulets and J-boxes for inspection.
Pulled all the wires up out of the J-boxes. Pulled the endcaps and ground
clips off (unique components of the Integra product). Couldn't find anything
suspicious. Shot it with the megger again, and it was all clear. But no sign
of anything that could have been shorted. We put everything back together
and shot it again. Dead short! Aiyeeeee!



Call it a day. Go home. I couldn't get back to that site until about the
same time the next day. Foggy again. Only took 1 helper with me this time.
We completely repeated the entire exercise, with exactly the same results.
By now, I was pretty sure this solar stuff wasn't my calling. I've always
been regarded as a gifted trouble-shooter and all I could say at this point
was that I didn't know _____! All signs pointed to it being associated with
one of the J-boxes or the endcaps or the ground clips, but there was NOT a
thing we could see. Oh, well. I would have to come back another day. When I
went back, I took the same helper and made sure I had all day if necessary
to fix the problem. No matter what it turned out to be. We planned to take
it apart 1 piece at a time and re-shoot it with the megger after each step.
I left my helper on the ground with the megger while I took it apart on the
roof, 1 screw at a time. Again.



Well, lo and behold, he hollers up that "It's clear" when I pulled the cover
off one of the 2-gang bell boxes. Hadn't moved a wire. Just took the cover
off. Let me tell ya, I stuck my nose and four eyes in that box real close,
but didn't touch any wires. The box was a tight fit with those big,
sealant-filled blue wire nuts that came with the Solarex Kit, but I still
couldn't see anything wierd.



"Shoot it again."



"All clear, boss."



I put the cover back on and installed all the screws. "Shoot it again."



"Dead short." We had a talk later about shouting things like "Dead short" on
the jobsite, but I won't get into all that right now.



I took out one of the cover screws. "Shoot it again." Same answer from the
ground.



I took out a second screw. "Shoot it again." This time the reply was
different. I took out the third screw and we repeated the process. Still
clear. And the fourth. Still clear. WTF? I lifted the cover for what seemed
like the hundredth time. I studied the nested wires, all neatly and
systematically put into what I had thought would be their final resting
place... Days before and time and time again at this point.



I began gently lifting the wires out so they all stood up like dandelions in
a spring lawn. I inspected them for the nth time. Looking for a stray strand
outside its protective hat. Nope. Overtightened wire nut with the spring or
a conductor coming out the tip? Nope. But what's this little, nearly
imperceptible dent in the side of this wire nut? As I looked closer, I could
see that it was round, flat bottomed and about the same diameter as a 6-32
screw. Hmmmm. I rolled the wires back into their resting position. Uh, huh.
This particular wire nut's natural home was directly under the cover screw
which had cleared the fault when removed and the dent lined up perfectly.
The screw could just barely be long enough to pierce the plastic and contact
the wire-spring.



I replaced the wire nut, repositioned the conductors to make sure we
wouldn't have a repeat, and buttoned up the J-box. I put the wirenut in my
pocket for later reference. One more megger shot proved the system to be all
clear. We could now energize the DC and do our Voc & Isc testing prior to
startup. Thank goodness the sun was shining. I wasn't happy about this whole
ordeal, but it was a good thing we caught it with the megger before we put
the power to it.



That wire nut became the first exhibit in what became my collection of
training materials for the "what can go wrong and why we do these
procedures" trainings. Verification that cover and mounting screws cannot
come in contact with energized equipment was officially put in the
checklist. All cover & mounting screws in all types of enclosures. There
would be no exceptions. There would be no excuses. I actually had to write
one guy up for a violation of this at one point. Good thing we caught that
one with the megger before putting the power to it.



I would posit that at least one of the recent PV fires would absolutely have
been prevented if the installer followed the procedure described above. Too
bad most don't. Kudos to those of you who do. It's only a matter of time
until more and more of these AVOIDABLE problems surface.



If you don't have a megger, get one. If you have one, use it! The Fluke 1520
is a nice unit. I recommend it over analog models. I cut my teeth with
analog gear, but really like my 1520. A lot! Rugged instrument that gives
you an actual number to write on your commissioning sheet. In addition to
Megohms, it also does VAC, Lo Ohms, Continuity, has a display backlight,
Lock and Zero functions and my favorite.... Battery Check! Reads out an
actual % value for your battery condition. Nice! Uses 4 "C" cells.



I hope more hands go up on this topic. Thanks for asking, Keith.



Peace and Palm Trees everybody,



Matt Lafferty



_____

From: re-wrenches-bounces at lists.re-wrenches.org
[mailto:re-wrenches-bounces at lists.re-wrenches.org] On Behalf Of Keith Cronin
Sent: Monday, April 27, 2009 2:37 PM
To: RE-Wrenches


Subject: [RE-wrenches] To Megger or not to Megger



Hi

I was wondering, by a show of hands, how many of you megger every project?

Do you have a cut off- like if it is "x" sized system, you will or decide to
opt out of performing this task?




_______________________________________________
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Matt Lafferty
2009-04-28 13:55:51 UTC
Permalink
RE: Suggested replacements for Fluke 1520 and "pricey meters"... Good News
below!

Another Wrench sent me a note off-list last night, asking how much a
"muggering" would cost. Here's what I sent him:

When I got that 1520 it was just over $600. I just checked online and find
that it's a discontinued item... Bummer!

Fluke recommends the 1587 or the 1507 or the 1503. They also mention the
1577, but it's an ugly stepsister, or maybe a retarded adopted relative, to
the 1587.

The 1587 is basically a multimeter that also has a <TEST> button to
discharge a high voltage shock into the sample under test... It runs about
$620 from standard distributors.
<http://us.fluke.com/usen/products/Fluke+1587+1577.htm?catalog_name=FlukeUni
tedStates>
http://us.fluke.com/usen/products/Fluke+1587+1577.htm?catalog_name=FlukeUnit
edStates You can get it for $522 here:
<http://www.testequipmentdepot.com/fluke/megohmmeters/1577_87.htm>
http://www.testequipmentdepot.com/fluke/megohmmeters/1577_87.htm NOTE: It
does not test at 10A in DMM mode which means it wouldn't be able to test
short-circuit current in strings. Don't bother with the 1577!

The 1507 & 1503 are more robust equipment. You can check them out here:
<http://us.fluke.com/usen/products/features.htm?cs_id=35391(FlukeProducts)&c
ategory=HMA(FlukeProducts>
http://us.fluke.com/usen/products/features.htm?cs_id=35391(FlukeProducts)&ca
tegory=HMA(FlukeProducts) While they do measure AC & DC Voltages to 600V as
well as some lower ohm & continuity work, they are really more tailored to
being a megger. The 1503 will suffice for most of what I expect you will get
into, but there are some features on the 1507 that might make it worth
considering. Mind you, I haven't looked at at price on either yet, so that
last comment may just be noises coming out my ass.

The 1507 has a Compare function which basically sets up a Pass/Fail value so
you can quickly run through repeated tests. This would be useful for doing
larger systems where you are testing dozens or hundreds of circuits at a
time. For my purposes, I want my guys to think a little more than "Buzz =
OK" and I want them to write an actual tested value down on a piece of paper
so this is not a big plus to me.

The 1507 also does Polarization Index and Absorption Ratios. These are more
advanced di-electric tests that you are not likely to need in smaller scale
PV. Use of these features would come into play when playing with real
high-voltage gear or transformers. Might also come into play on
super-sensitive equipment. They might also be used to assess older or aging
underground or overhead feeders.

The 1507 & 1503 both have an Earth Bond Resistance function which is likely
to become more of an issue in the future. This feature lets you test the
resistance between a grounding electrode or a grounding electrode conductor
and actual earth. Another use for this feature would be to set the output to
1kV, connect the alligator jaw to one of Mike Gripando's extremities and use
the probe lead as a tongue depressor while you push <TEST>. This feature
used to be in a single-purpose tester that ran >$2K. They also both have
backlit displays which comes in real handy out in the field.

The primary features you want are: 500V & 1kV Test Voltage and 2 Gohms
(2,000 Megaohms) or above for the top end of the range. Any of the 3 meet
this spec.

Well, I just checked prices for the 1503 & 1507 and I'm pleasantly
surprised. The 1503 ranges from about $291-$370. Here's the place I found it
for $291 <http://www.testequipmentdepot.com/fluke/megohmmeters/1503.htm>
http://www.testequipmentdepot.com/fluke/megohmmeters/1503.htm That's marked
down from the regular price of $342.

The 1507 ranges from about $385 to $500. Here's where I found it for $385...
<http://www.testequipmentdepot.com/fluke/megohmmeters/1507.htm>
http://www.testequipmentdepot.com/fluke/megohmmeters/1507.htm That's a
special price, for you only, down from $454.

All things considered if I were in your shoes, I'd go for the 1503. That
give you a solid megger that you can dedicate to that purpose for a
reasonale muggering. If it were me, in Matt's shoes... Oh, what am I saying?
I've already got mine and I just found out I paid too much for it! But I
have Battery Check... Neener neener neener!

Be safe out there!

Matt Lafferty


I hope more hands go up on this topic. Thanks for asking, Keith.

Peace and Palm Trees everybody,

Matt Lafferty


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Joel Davidson
2009-04-28 14:44:37 UTC
Permalink
Hello Matt,

Both hands up here too. One in the factory and one in the field. I require technicians to use the UL 1703 standard dc test potential of 2 times maximum system voltage plus 1,000 volts (or 3,000 vdc). Be safe. Wear your gloves.

Joel Davidson
----- Original Message -----
From: Matt Lafferty
To: 'RE-wrenches'
Sent: Monday, April 27, 2009 8:08 PM
Subject: Re: [RE-wrenches] To Megger or not to Megger


Hi Keith,

Both hands up here. From day 1 in PV.

Every single field-installed current carrying conductor to the point of termination. AC & DC. BEFORE energizing them! One megger lead on the conductor, the other on the raceway or ground-wire. Megger @ 1kV. Must be greater than 250 Megohms to pass. Record the values on your commissioning sheet.

I only meggered the actual arrays on projects where it was a requirement and I only did that following specific procedures provided by the module manufacturer. No procedure from the mfr = No array megger.

I believe it's a critical thing to do as part of the commissioning. But then again, I don't like ground faults or fires.

I'll never forget a couple of head scratchers that the megger found.... One was a perfectly fine, 6' long piece of Orange #12 XHHW-2 that would only pull 40 Megohms installed in EMT. Pulled it out and replaced it. Inspected it for any visible flaws. None found. Not a scratch or scuff. Used it as a training tool for my guys. Hung it on the wall over my desk as a handy reminder. If anybody wants a picture...

The other was interesting, too. The very first PV system I ever installed. Was shooting the DC circuits from the inverter all the way to the connector on the output jumper cables at the modules. Megger showed dead short on one wire. Fluke 79 on ohms showed clear. Hit it with the megger again. Dead short. I'm known for being anal about conduit and wire installation, so this was quite unexpected, not to mention a little embarrassing. This happened to be a Solarex Millennia Integra system with an Omnion inverter and the array happened to be scattered all over this roof. For those of you who who have dealt with that situation, you'll understand what a cluster-*$#! that is... Especially being my very first PV system and all... I wasn't anywhere near confident that I had a clue by that point. All ready to see my first install fire up and this happens.

It was my first install and I had 3 people getting paid prevailing wages to learn... I was learning too, but I wasn't making anywhere near prevailing wages, let me tell ya. Well, it was early January, late in the day and foggy as foggy gets, but we went back onto the roof anyway. Yeah... Overtime for everybody but me. We opened up the condulets and J-boxes for inspection. Pulled all the wires up out of the J-boxes. Pulled the endcaps and ground clips off (unique components of the Integra product). Couldn't find anything suspicious. Shot it with the megger again, and it was all clear. But no sign of anything that could have been shorted. We put everything back together and shot it again. Dead short! Aiyeeeee!

Call it a day. Go home. I couldn't get back to that site until about the same time the next day. Foggy again. Only took 1 helper with me this time. We completely repeated the entire exercise, with exactly the same results. By now, I was pretty sure this solar stuff wasn't my calling. I've always been regarded as a gifted trouble-shooter and all I could say at this point was that I didn't know _____! All signs pointed to it being associated with one of the J-boxes or the endcaps or the ground clips, but there was NOT a thing we could see. Oh, well. I would have to come back another day. When I went back, I took the same helper and made sure I had all day if necessary to fix the problem. No matter what it turned out to be. We planned to take it apart 1 piece at a time and re-shoot it with the megger after each step. I left my helper on the ground with the megger while I took it apart on the roof, 1 screw at a time. Again.

Well, lo and behold, he hollers up that "It's clear" when I pulled the cover off one of the 2-gang bell boxes. Hadn't moved a wire. Just took the cover off. Let me tell ya, I stuck my nose and four eyes in that box real close, but didn't touch any wires. The box was a tight fit with those big, sealant-filled blue wire nuts that came with the Solarex Kit, but I still couldn't see anything wierd.

"Shoot it again."

"All clear, boss."

I put the cover back on and installed all the screws. "Shoot it again."

"Dead short." We had a talk later about shouting things like "Dead short" on the jobsite, but I won't get into all that right now.

I took out one of the cover screws. "Shoot it again." Same answer from the ground.

I took out a second screw. "Shoot it again." This time the reply was different. I took out the third screw and we repeated the process. Still clear. And the fourth. Still clear. WTF? I lifted the cover for what seemed like the hundredth time. I studied the nested wires, all neatly and systematically put into what I had thought would be their final resting place... Days before and time and time again at this point.

I began gently lifting the wires out so they all stood up like dandelions in a spring lawn. I inspected them for the nth time. Looking for a stray strand outside its protective hat. Nope. Overtightened wire nut with the spring or a conductor coming out the tip? Nope. But what's this little, nearly imperceptible dent in the side of this wire nut? As I looked closer, I could see that it was round, flat bottomed and about the same diameter as a 6-32 screw. Hmmmm. I rolled the wires back into their resting position. Uh, huh. This particular wire nut's natural home was directly under the cover screw which had cleared the fault when removed and the dent lined up perfectly. The screw could just barely be long enough to pierce the plastic and contact the wire-spring.

I replaced the wire nut, repositioned the conductors to make sure we wouldn't have a repeat, and buttoned up the J-box. I put the wirenut in my pocket for later reference. One more megger shot proved the system to be all clear. We could now energize the DC and do our Voc & Isc testing prior to startup. Thank goodness the sun was shining. I wasn't happy about this whole ordeal, but it was a good thing we caught it with the megger before we put the power to it.

That wire nut became the first exhibit in what became my collection of training materials for the "what can go wrong and why we do these procedures" trainings. Verification that cover and mounting screws cannot come in contact with energized equipment was officially put in the checklist. All cover & mounting screws in all types of enclosures. There would be no exceptions. There would be no excuses. I actually had to write one guy up for a violation of this at one point. Good thing we caught that one with the megger before putting the power to it.

I would posit that at least one of the recent PV fires would absolutely have been prevented if the installer followed the procedure described above. Too bad most don't. Kudos to those of you who do. It's only a matter of time until more and more of these AVOIDABLE problems surface.

If you don't have a megger, get one. If you have one, use it! The Fluke 1520 is a nice unit. I recommend it over analog models. I cut my teeth with analog gear, but really like my 1520. A lot! Rugged instrument that gives you an actual number to write on your commissioning sheet. In addition to Megohms, it also does VAC, Lo Ohms, Continuity, has a display backlight, Lock and Zero functions and my favorite.... Battery Check! Reads out an actual % value for your battery condition. Nice! Uses 4 "C" cells.

I hope more hands go up on this topic. Thanks for asking, Keith.

Peace and Palm Trees everybody,

Matt Lafferty


------------------------------------------------------------------------------
From: re-wrenches-bounces at lists.re-wrenches.org [mailto:re-wrenches-bounces at lists.re-wrenches.org] On Behalf Of Keith Cronin
Sent: Monday, April 27, 2009 2:37 PM
To: RE-Wrenches
Subject: [RE-wrenches] To Megger or not to Megger


Hi

I was wondering, by a show of hands, how many of you megger every project?

Do you have a cut off- like if it is "x" sized system, you will or decide to opt out of performing this task?





------------------------------------------------------------------------------


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David Katz
2009-04-28 04:49:55 UTC
Permalink
Wrenches,
Here is a really scary link. the guy is selling a book for $50 that
shows you how you can build your own PV module for $125.
http://www.power4home.com/index.php?hop=roeib
Cheers

David Katz


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robert ellison
2009-04-28 10:24:25 UTC
Permalink
Just went to check the Fluke 1520 price. Looks like it is discontinued.
They do have a couple suggested replacements.

Just for reference,
Bob

On Mon, Apr 27, 2009 at 11:08 PM, Matt Lafferty <gilligan06 at gmail.com>wrote:

> Hi Keith,
>
> Both hands up here. From day 1 in PV.
>
> Every single field-installed current carrying conductor to the point of
> termination. AC & DC. BEFORE energizing them! One megger lead on the
> conductor, the other on the raceway or ground-wire. Megger @ 1kV. Must be
> greater than 250 Megohms to pass. Record the values on your commissioning
> sheet.
>
> I only meggered the actual arrays on projects where it was a requirement
> and I only did that following specific procedures provided by the module
> manufacturer. No procedure from the mfr = No array megger.
>
> I believe it's a critical thing to do as part of the commissioning. But
> then again, I don't like ground faults or fires.
>
> I'll never forget a couple of head scratchers that the megger found.... One
> was a perfectly fine, 6' long piece of Orange #12 XHHW-2 that would only
> pull 40 Megohms installed in EMT. Pulled it out and replaced it. Inspected
> it for any visible flaws. None found. Not a scratch or scuff. Used it as a
> training tool for my guys. Hung it on the wall over my desk as a handy
> reminder. If anybody wants a picture...
>
> The other was interesting, too. The very first PV system I ever installed. Was
> shooting the DC circuits from the inverter all the way to the connector on
> the output jumper cables at the modules. Megger showed dead short on one
> wire. Fluke 79 on ohms showed clear. Hit it with the megger again. Dead
> short. I'm known for being anal about conduit and wire installation, so
> this was quite unexpected, not to mention a little embarrassing. This
> happened to be a Solarex Millennia Integra system with an Omnion inverter
> and the array happened to be scattered all over this roof. For those of you
> who who have dealt with that situation, you'll understand what a
> cluster-*$#! that is... Especially being my very first PV system and
> all... I wasn't anywhere near confident that I had a clue by that point. All
> ready to see my first install fire up and this happens.
>
> It was my first install and I had 3 people getting paid prevailing wages to
> learn... I was learning too, but I wasn't making anywhere near prevailing
> wages, let me tell ya. Well, it was early January, late in the day and
> foggy as foggy gets, but we went back onto the roof anyway. Yeah... Overtime
> for everybody but me. We opened up the condulets and J-boxes for
> inspection. Pulled all the wires up out of the J-boxes. Pulled the endcaps
> and ground clips off *(unique components of the Integra product)*.
> Couldn't find anything suspicious. Shot it with the megger again, and it was
> all clear. But no sign of anything that could have been shorted. We put
> everything back together and shot it again. Dead short! Aiyeeeee!
>
> Call it a day. Go home. I couldn't get back to that site until about the
> same time the next day. Foggy again. Only took 1 helper with me this time.
> We completely repeated the entire exercise, with exactly the same results.
> By now, I was pretty sure this solar stuff wasn't my calling. I've always
> been regarded as a gifted trouble-shooter and all I could say at this point
> was that I didn't know _____! All signs pointed to it being associated with
> one of the J-boxes or the endcaps or the ground clips, but there was NOT a
> thing we could see. Oh, well. I would have to come back another day. When
> I went back, I took the same helper and made sure I had all day if necessary
> to fix the problem. No matter what it turned out to be. We planned to
> take it apart 1 piece at a time and re-shoot it with the megger after each
> step. I left my helper on the ground with the megger while I took it apart
> on the roof, 1 screw at a time. Again.
>
> Well, lo and behold, he hollers up that "It's clear" when I pulled the
> cover off one of the 2-gang bell boxes. Hadn't moved a wire. Just took the
> cover off. Let me tell ya, I stuck my nose and four eyes in that box real
> close, but didn't touch any wires. The box was a tight fit with those big,
> sealant-filled blue wire nuts that came with the Solarex Kit, but I still
> couldn't see anything wierd.
>
> "Shoot it again."
>
> "All clear, boss."
>
> I put the cover back on and installed all the screws. "Shoot it again."
>
> "Dead short." We had a talk later about shouting things like "Dead short"
> on the jobsite, but I won't get into all that right now.
>
> I took out one of the cover screws. "Shoot it again." Same answer from the
> ground.
>
> I took out a second screw. "Shoot it again." This time the reply was
> different. I took out the third screw and we repeated the process. Still
> clear. And the fourth. Still clear. WTF? I lifted the cover for what seemed
> like the hundredth time. I studied the nested wires, all neatly and
> systematically put into what I had thought would be their final resting
> place... Days before and time and time again at this point.
>
> I began gently lifting the wires out so they all stood up like dandelions
> in a spring lawn. I inspected them for the nth time. Looking for a stray
> strand outside its protective hat. Nope. Overtightened wire nut with the
> spring or a conductor coming out the tip? Nope. But what's this little,
> nearly imperceptible dent in the side of this wire nut? As I looked closer,
> I could see that it was round, flat bottomed and about the same diameter as
> a 6-32 screw. Hmmmm. I rolled the wires back into their resting position.
> Uh, huh. This particular wire nut's natural home was directly under the
> cover screw which had cleared the fault when removed and the dent lined up
> perfectly. The screw could just barely be long enough to pierce the plastic
> and contact the wire-spring.
>
> I replaced the wire nut, repositioned the conductors to make sure we
> wouldn't have a repeat, and buttoned up the J-box. I put the wirenut in my
> pocket for later reference. One more megger shot proved the system to be all
> clear. We could now energize the DC and do our Voc & Isc testing prior to
> startup. Thank goodness the sun was shining. I wasn't happy about this whole
> ordeal, but it was a good thing we caught it with the megger before we put
> the power to it.
>
> That wire nut became the first exhibit in what became my collection of
> training materials for the "what can go wrong and why we do these
> procedures" trainings. Verification that cover and mounting screws cannot
> come in contact with energized equipment was officially put in the
> checklist. *All *cover & mounting screws in *all* types of enclosures.
> There would be no exceptions. There would be no excuses. I actually had to
> write one guy up for a violation of this at one point. Good thing we caught
> that one with the megger before putting the power to it.
>
> I would posit that at least one of the recent PV fires would *absolutely
> have been prevented* if the installer followed the procedure described
> above. Too bad most don't. Kudos to those of you who do. It's only a
> matter of time until more and more of these AVOIDABLE problems surface.
>
> If you don't have a megger, get one. If you have one, use it! The Fluke
> 1520 is a nice unit. I recommend it over analog models. I cut my teeth with
> analog gear, but really like my 1520. A lot! Rugged instrument that gives
> you an actual number to write on your commissioning sheet. In addition to
> Megohms, it also does VAC, Lo Ohms, Continuity, has a display backlight,
> Lock and Zero functions and my favorite.... Battery Check! Reads out an
> actual % value for your battery condition. Nice! Uses 4 "C" cells.
>
> I hope more hands go up on this topic. Thanks for asking, Keith.
>
> Peace and Palm Trees everybody,
>
> Matt Lafferty
>
> ------------------------------
> *From:* re-wrenches-bounces at lists.re-wrenches.org [mailto:
> re-wrenches-bounces at lists.re-wrenches.org] *On Behalf Of *Keith Cronin
> *Sent:* Monday, April 27, 2009 2:37 PM
> *To:* RE-Wrenches
> *Subject:* [RE-wrenches] To Megger or not to Megger
>
> Hi
>
> I was wondering, by a show of hands, how many of you megger every project?
>
> Do you have a cut off- like if it is "x" sized system, you will or decide
> to opt out of performing this task?
>
>
> _______________________________________________
> List sponsored by Home Power magazine
>
> List Address: RE-wrenches at lists.re-wrenches.org
>
> Options & settings:
> http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org
>
> List-Archive:
> http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org
>
> List rules & etiquette:
> www.re-wrenches.org/etiquette.htm
>
> Check out participant bios:
> www.members.re-wrenches.org
>
>
>
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Joel Davidson
2009-04-28 14:44:37 UTC
Permalink
Hello Matt,

Both hands up here too. One in the factory and one in the field. I require technicians to use the UL 1703 standard dc test potential of 2 times maximum system voltage plus 1,000 volts (or 3,000 vdc). Be safe. Wear your gloves.

Joel Davidson
----- Original Message -----
From: Matt Lafferty
To: 'RE-wrenches'
Sent: Monday, April 27, 2009 8:08 PM
Subject: Re: [RE-wrenches] To Megger or not to Megger


Hi Keith,

Both hands up here. From day 1 in PV.

Every single field-installed current carrying conductor to the point of termination. AC & DC. BEFORE energizing them! One megger lead on the conductor, the other on the raceway or ground-wire. Megger @ 1kV. Must be greater than 250 Megohms to pass. Record the values on your commissioning sheet.

I only meggered the actual arrays on projects where it was a requirement and I only did that following specific procedures provided by the module manufacturer. No procedure from the mfr = No array megger.

I believe it's a critical thing to do as part of the commissioning. But then again, I don't like ground faults or fires.

I'll never forget a couple of head scratchers that the megger found.... One was a perfectly fine, 6' long piece of Orange #12 XHHW-2 that would only pull 40 Megohms installed in EMT. Pulled it out and replaced it. Inspected it for any visible flaws. None found. Not a scratch or scuff. Used it as a training tool for my guys. Hung it on the wall over my desk as a handy reminder. If anybody wants a picture...

The other was interesting, too. The very first PV system I ever installed. Was shooting the DC circuits from the inverter all the way to the connector on the output jumper cables at the modules. Megger showed dead short on one wire. Fluke 79 on ohms showed clear. Hit it with the megger again. Dead short. I'm known for being anal about conduit and wire installation, so this was quite unexpected, not to mention a little embarrassing. This happened to be a Solarex Millennia Integra system with an Omnion inverter and the array happened to be scattered all over this roof. For those of you who who have dealt with that situation, you'll understand what a cluster-*$#! that is... Especially being my very first PV system and all... I wasn't anywhere near confident that I had a clue by that point. All ready to see my first install fire up and this happens.

It was my first install and I had 3 people getting paid prevailing wages to learn... I was learning too, but I wasn't making anywhere near prevailing wages, let me tell ya. Well, it was early January, late in the day and foggy as foggy gets, but we went back onto the roof anyway. Yeah... Overtime for everybody but me. We opened up the condulets and J-boxes for inspection. Pulled all the wires up out of the J-boxes. Pulled the endcaps and ground clips off (unique components of the Integra product). Couldn't find anything suspicious. Shot it with the megger again, and it was all clear. But no sign of anything that could have been shorted. We put everything back together and shot it again. Dead short! Aiyeeeee!

Call it a day. Go home. I couldn't get back to that site until about the same time the next day. Foggy again. Only took 1 helper with me this time. We completely repeated the entire exercise, with exactly the same results. By now, I was pretty sure this solar stuff wasn't my calling. I've always been regarded as a gifted trouble-shooter and all I could say at this point was that I didn't know _____! All signs pointed to it being associated with one of the J-boxes or the endcaps or the ground clips, but there was NOT a thing we could see. Oh, well. I would have to come back another day. When I went back, I took the same helper and made sure I had all day if necessary to fix the problem. No matter what it turned out to be. We planned to take it apart 1 piece at a time and re-shoot it with the megger after each step. I left my helper on the ground with the megger while I took it apart on the roof, 1 screw at a time. Again.

Well, lo and behold, he hollers up that "It's clear" when I pulled the cover off one of the 2-gang bell boxes. Hadn't moved a wire. Just took the cover off. Let me tell ya, I stuck my nose and four eyes in that box real close, but didn't touch any wires. The box was a tight fit with those big, sealant-filled blue wire nuts that came with the Solarex Kit, but I still couldn't see anything wierd.

"Shoot it again."

"All clear, boss."

I put the cover back on and installed all the screws. "Shoot it again."

"Dead short." We had a talk later about shouting things like "Dead short" on the jobsite, but I won't get into all that right now.

I took out one of the cover screws. "Shoot it again." Same answer from the ground.

I took out a second screw. "Shoot it again." This time the reply was different. I took out the third screw and we repeated the process. Still clear. And the fourth. Still clear. WTF? I lifted the cover for what seemed like the hundredth time. I studied the nested wires, all neatly and systematically put into what I had thought would be their final resting place... Days before and time and time again at this point.

I began gently lifting the wires out so they all stood up like dandelions in a spring lawn. I inspected them for the nth time. Looking for a stray strand outside its protective hat. Nope. Overtightened wire nut with the spring or a conductor coming out the tip? Nope. But what's this little, nearly imperceptible dent in the side of this wire nut? As I looked closer, I could see that it was round, flat bottomed and about the same diameter as a 6-32 screw. Hmmmm. I rolled the wires back into their resting position. Uh, huh. This particular wire nut's natural home was directly under the cover screw which had cleared the fault when removed and the dent lined up perfectly. The screw could just barely be long enough to pierce the plastic and contact the wire-spring.

I replaced the wire nut, repositioned the conductors to make sure we wouldn't have a repeat, and buttoned up the J-box. I put the wirenut in my pocket for later reference. One more megger shot proved the system to be all clear. We could now energize the DC and do our Voc & Isc testing prior to startup. Thank goodness the sun was shining. I wasn't happy about this whole ordeal, but it was a good thing we caught it with the megger before we put the power to it.

That wire nut became the first exhibit in what became my collection of training materials for the "what can go wrong and why we do these procedures" trainings. Verification that cover and mounting screws cannot come in contact with energized equipment was officially put in the checklist. All cover & mounting screws in all types of enclosures. There would be no exceptions. There would be no excuses. I actually had to write one guy up for a violation of this at one point. Good thing we caught that one with the megger before putting the power to it.

I would posit that at least one of the recent PV fires would absolutely have been prevented if the installer followed the procedure described above. Too bad most don't. Kudos to those of you who do. It's only a matter of time until more and more of these AVOIDABLE problems surface.

If you don't have a megger, get one. If you have one, use it! The Fluke 1520 is a nice unit. I recommend it over analog models. I cut my teeth with analog gear, but really like my 1520. A lot! Rugged instrument that gives you an actual number to write on your commissioning sheet. In addition to Megohms, it also does VAC, Lo Ohms, Continuity, has a display backlight, Lock and Zero functions and my favorite.... Battery Check! Reads out an actual % value for your battery condition. Nice! Uses 4 "C" cells.

I hope more hands go up on this topic. Thanks for asking, Keith.

Peace and Palm Trees everybody,

Matt Lafferty


------------------------------------------------------------------------------
From: re-wrenches-bounces at lists.re-wrenches.org [mailto:re-wrenches-bounces at lists.re-wrenches.org] On Behalf Of Keith Cronin
Sent: Monday, April 27, 2009 2:37 PM
To: RE-Wrenches
Subject: [RE-wrenches] To Megger or not to Megger


Hi

I was wondering, by a show of hands, how many of you megger every project?

Do you have a cut off- like if it is "x" sized system, you will or decide to opt out of performing this task?





------------------------------------------------------------------------------


_______________________________________________
List sponsored by Home Power magazine

List Address: RE-wrenches at lists.re-wrenches.org

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Jeff Yago
2009-04-28 14:59:04 UTC
Permalink
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Jim MacDonald
2012-02-09 21:44:47 UTC
Permalink
Hello wrenches

I am in Central America and looking to suggest customers buy efficient LEDs for illumination in their 120V-wired homes, connected to local power grids with less-than-desirable power quality.

I see that so many manus claim long life for the LEDs, in the tens of thousands of hours, yet so few if any back it up with a decent warranty.

Folks are hesitant to make this investment, believing that voltage surges or dips could destroy the LEDs.

Has anyone heard of LED lights' lives ending prematurely due to grid events?
Would inline surge protectors [something small to be installed immediately downstream of the breaker in the home's main panel) be helpful, and if so, does anyone have any recommended brands?

thanks
Jim MacDonald
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Larry Crutcher, Starlight Solar Power Systems
2012-02-09 22:25:24 UTC
Permalink
Still looking for about 200 PV module junction boxes that are 5" x 7". see attached picture. Please email me off list. larry at starlightsolar.com



Larry Crutcher
Starlight Solar Power Systems
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Larry Crutcher, Starlight Solar Power Systems
2012-02-09 22:25:24 UTC
Permalink
Still looking for about 200 PV module junction boxes that are 5" x 7". see attached picture. Please email me off list. larry at starlightsolar.com



Larry Crutcher
Starlight Solar Power Systems
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toddcory
2012-02-09 23:54:16 UTC
Permalink
i have some personal experience with led light bulbs. i put them outside because the cfl floodlights are very s-l-o-w to warm up to full brightness.

1) leds are still slightly less efficient (lumens per watt) than cfl's
2) led light bulbs (2 different brands) throw out an ungodly amount of rfi... want to listen to a conversation on the 2 meter ham radio or listen to a weak fm broadcast station or watch channel 6 on the tee-vee? go shut off the led lights off first.

my conclusion? led light bulbs are not ready for prime time.

todd (still using my 25+ year old phillips dulux cfls)



On Thursday, February 9, 2012 1:44pm, "Jim MacDonald" <jmac at solaresystems.com> said:




Hello wrenches

I am in Central America and looking to suggest customers buy efficient LEDs for illumination in their 120V-wired homes, connected to local power grids with less-than-desirable power quality.

I see that so many manus claim long life for the LEDs, in the tens of thousands of hours, yet so few if any back it up with a decent warranty.

Folks are hesitant to make this investment, believing that voltage surges or dips could destroy the LEDs.

Has anyone heard of LED lights' lives ending prematurely due to grid events?
Would inline surge protectors [something small to be installed immediately downstream of the breaker in the home's main panel) be helpful, and if so, does anyone have any recommended brands?

thanks
Jim MacDonald


Sent from Finest Planet WebMail.
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Ray Walters
2012-02-10 01:45:02 UTC
Permalink
Personally I love my latest LED lights. They have gotten substantially
better just in the past year. We have some 8 watt units in our kitchen
that illuminate just like a 35 watt halogen, beautiful color rendition,
not that blue they used to have.
I especially like my new 1000 lumen spotlight that lights up brighter
than a car head light in a package slightly larger than the old mini mag
flash lights.
However, I have no experience with ham radio, or theRF interference
issue. We're WiFi, and cell at our house. I do some audio recording,
etc. and haven't noticed any extra buzz from the several LEDs I have in
my basement studio.

Ray

On 2/9/2012 4:54 PM, toddcory at finestplanet.com wrote:
>
> i have some personal experience with led light bulbs. i put them
> outside because the cfl floodlights are very s-l-o-w to warm up to
> full brightness.
>
> 1) leds are still slightly less efficient (lumens per watt) than cfl's
>
> 2) led light bulbs (2 different brands) throw out an ungodly amount of
> rfi... want to listen to a conversation on the 2 meter ham radio or
> listen to a weak fm broadcast station or watch channel 6 on the
> tee-vee? go shut off the led lights off first.
>
> my conclusion? led light bulbs are not ready for prime time.
>
> todd (still using my 25+ year old phillips dulux cfls)
>
> On Thursday, February 9, 2012 1:44pm, "Jim MacDonald"
> <jmac at solaresystems.com> said:
>
> Hello wrenches
>
> I am in Central America and looking to suggest customers buy efficient
> LEDs for illumination in their 120V-wired homes, connected to local
> power grids with less-than-desirable power quality.
>
> I see that so many manus claim long life for the LEDs, in the tens of
> thousands of hours, yet so few if any back it up with a decent warranty.
>
> Folks are hesitant to make this investment, believing that voltage
> surges or dips could destroy the LEDs.
>
> Has anyone heard of LED lights' lives ending prematurely due to grid
> events?
>
> Would inline surge protectors [something small to be installed
> immediately downstream of the breaker in the home's main panel) be
> helpful, and if so, does anyone have any recommended brands?
>
> thanks
>
> Jim MacDonald
>
>
>
>
> Sent from Finest Planet WebMail.
>
>
> _______________________________________________
> List sponsored by Home Power magazine
>
> List Address: RE-wrenches at lists.re-wrenches.org
>
> Options& settings:
> http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org
>
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>
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Jesse Dahl
2012-02-10 13:32:18 UTC
Permalink
I don't know about spikes or grid events, but my home is 3/4 LED and have zero complaints. The warranty on them is a little weak compared to life cycle...... All of mine vary in K rating and lumens and work beautifully.



Sent from my iPhone

On Feb 9, 2012, at 7:45 PM, Ray Walters <ray at solarray.com> wrote:

> Personally I love my latest LED lights. They have gotten substantially better just in the past year. We have some 8 watt units in our kitchen that illuminate just like a 35 watt halogen, beautiful color rendition, not that blue they used to have.
> I especially like my new 1000 lumen spotlight that lights up brighter than a car head light in a package slightly larger than the old mini mag flash lights.
> However, I have no experience with ham radio, or theRF interference issue. We're WiFi, and cell at our house. I do some audio recording, etc. and haven't noticed any extra buzz from the several LEDs I have in my basement studio.
>
> Ray
>
> On 2/9/2012 4:54 PM, toddcory at finestplanet.com wrote:
>>
>> i have some personal experience with led light bulbs. i put them outside because the cfl floodlights are very s-l-o-w to warm up to full brightness.
>>
>> 1) leds are still slightly less efficient (lumens per watt) than cfl's
>> 2) led light bulbs (2 different brands) throw out an ungodly amount of rfi... want to listen to a conversation on the 2 meter ham radio or listen to a weak fm broadcast station or watch channel 6 on the tee-vee? go shut off the led lights off first.
>>
>> my conclusion? led light bulbs are not ready for prime time.
>>
>> todd (still using my 25+ year old phillips dulux cfls)
>>
>>
>>
>> On Thursday, February 9, 2012 1:44pm, "Jim MacDonald" <jmac at solaresystems.com> said:
>>
>> Hello wrenches
>>
>> I am in Central America and looking to suggest customers buy efficient LEDs for illumination in their 120V-wired homes, connected to local power grids with less-than-desirable power quality.
>>
>> I see that so many manus claim long life for the LEDs, in the tens of thousands of hours, yet so few if any back it up with a decent warranty.
>> Folks are hesitant to make this investment, believing that voltage surges or dips could destroy the LEDs.
>>
>> Has anyone heard of LED lights' lives ending prematurely due to grid events?
>> Would inline surge protectors [something small to be installed immediately downstream of the breaker in the home's main panel) be helpful, and if so, does anyone have any recommended brands?
>> thanks
>> Jim MacDonald
>>
>>
>>
>> Sent from Finest Planet WebMail.
>>
>>
>> _______________________________________________
>> List sponsored by Home Power magazine
>>
>> List Address: RE-wrenches at lists.re-wrenches.org
>>
>> Options & settings:
>> http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org
>>
>> List-Archive: http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org
>>
>> List rules & etiquette:
>> www.re-wrenches.org/etiquette.htm
>>
>> Check out participant bios:
>> www.members.re-wrenches.org
>>
> _______________________________________________
> List sponsored by Home Power magazine
>
> List Address: RE-wrenches at lists.re-wrenches.org
>
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> http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org
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penobscotsolar
2012-02-10 13:54:26 UTC
Permalink
My home is 100% LED lighting, Kitchler undercounter, non dimmable Philips
Earthlights in closets, dimmable (might help with grid events...) Philips
Earthlights for the rest of the inside lighting and I am very happy with
all of it. Anything from warm white to daylight is available. They are
more expensive, but they are quality lights. The Earthlights are
equivalent to 40 watt and 60 watt incandescents and use 8-12 watts,
depending on the model.

Daryl



> I don't know about spikes or grid events, but my home is 3/4 LED and have
> zero complaints. The warranty on them is a little weak compared to life
> cycle...... All of mine vary in K rating and lumens and work beautifully.
>
>
>
> Sent from my iPhone
>
> On Feb 9, 2012, at 7:45 PM, Ray Walters <ray at solarray.com> wrote:
>
>> Personally I love my latest LED lights. They have gotten substantially
>> better just in the past year. We have some 8 watt units in our kitchen
>> that illuminate just like a 35 watt halogen, beautiful color rendition,
>> not that blue they used to have.
>> I especially like my new 1000 lumen spotlight that lights up brighter
>> than a car head light in a package slightly larger than the old mini mag
>> flash lights.
>> However, I have no experience with ham radio, or theRF interference
>> issue. We're WiFi, and cell at our house. I do some audio recording,
>> etc. and haven't noticed any extra buzz from the several LEDs I have in
>> my basement studio.
>>
>> Ray
>>
>> On 2/9/2012 4:54 PM, toddcory at finestplanet.com wrote:
>>>
>>> i have some personal experience with led light bulbs. i put them
>>> outside because the cfl floodlights are very s-l-o-w to warm up to full
>>> brightness.
>>>
>>> 1) leds are still slightly less efficient (lumens per watt) than cfl's
>>> 2) led light bulbs (2 different brands) throw out an ungodly amount of
>>> rfi... want to listen to a conversation on the 2 meter ham radio or
>>> listen to a weak fm broadcast station or watch channel 6 on the
>>> tee-vee? go shut off the led lights off first.
>>>
>>> my conclusion? led light bulbs are not ready for prime time.
>>>
>>> todd (still using my 25+ year old phillips dulux cfls)
>>>
>>>
>>>
>>> On Thursday, February 9, 2012 1:44pm, "Jim MacDonald"
>>> <jmac at solaresystems.com> said:
>>>
>>> Hello wrenches
>>>
>>> I am in Central America and looking to suggest customers buy efficient
>>> LEDs for illumination in their 120V-wired homes, connected to local
>>> power grids with less-than-desirable power quality.
>>>
>>> I see that so many manus claim long life for the LEDs, in the tens of
>>> thousands of hours, yet so few if any back it up with a decent
>>> warranty.
>>> Folks are hesitant to make this investment, believing that voltage
>>> surges or dips could destroy the LEDs.
>>>
>>> Has anyone heard of LED lights' lives ending prematurely due to grid
>>> events?
>>> Would inline surge protectors [something small to be installed
>>> immediately downstream of the breaker in the home's main panel) be
>>> helpful, and if so, does anyone have any recommended brands?
>>> thanks
>>> Jim MacDonald
>>>
>>>
>>>
>>> Sent from Finest Planet WebMail.
>>>
>>>
>>> _______________________________________________
>>> List sponsored by Home Power magazine
>>>
>>> List Address: RE-wrenches at lists.re-wrenches.org
>>>
>>> Options & settings:
>>> http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org
>>>
>>> List-Archive:
>>> http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org
>>>
>>> List rules & etiquette:
>>> www.re-wrenches.org/etiquette.htm
>>>
>>> Check out participant bios:
>>> www.members.re-wrenches.org
>>>
>> _______________________________________________
>> List sponsored by Home Power magazine
>>
>> List Address: RE-wrenches at lists.re-wrenches.org
>>
>> Options & settings:
>> http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org
>>
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> _______________________________________________
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Jim MacDonald
2012-02-22 19:33:43 UTC
Permalink
Hi wrenches

Does anyone know of a decent source where i could buy a converter that pulls 12V or 24v off a battery or load output of a CC and steps it down to 5 Vdc [preferably to a pre-wired USB female connector?]

I am not looking for anything that comes with a module included [like those keychain 1W solar phone chargers], but rather something that will remain hardwired [essentially a USB wall outlet located at the home's indoor DC load center.]

Also NOT looking for the car cigarette lighter adaptor variety, though it will serve the same purpose.

I would like to include these in simple DC-only PV systems for central america, and avoid involving truckstop inverters [going from DC to AC back to DC] to charge cell phones/ mp3 players/ etc.


thanks
Jim MacDonald
William Miller
2012-02-22 20:02:55 UTC
Permalink
Jim:

Astrodyne makes encapsulated modules that convert Dc to DC. You will need
to build an enclosure with fuses and a little circuit board. I have one in
the field providing 5 VDC and 12 VDC for a broadband internet relay. It
has worked well for years.

Here is a link for one
model:
http://www.astrodyne.com/ecatalog/usa/encapsulated-power-supply/ASD30-24S5

Or you can go the this page and choose your
own: http://www.astrodyne.com/ecatalog/usa/encapsulated-power-supply

Good luck.

William Miller



At 11:33 AM 2/22/2012, you wrote:
>Hi wrenches
>
>Does anyone know of a decent source where i could buy a converter that
>pulls 12V or 24v off a battery or load output of a CC and steps it down to
>5 Vdc [preferably to a pre-wired USB female connector?]
>
>I am not looking for anything that comes with a module included [like
>those keychain 1W solar phone chargers], but rather something that will
>remain hardwired [essentially a USB wall outlet located at the home's
>indoor DC load center.]
>
>Also NOT looking for the car cigarette lighter adaptor variety, though it
>will serve the same purpose.
>
>I would like to include these in simple DC-only PV systems for central
>america, and avoid involving truckstop inverters [going from DC to AC back
>to DC] to charge cell phones/ mp3 players/ etc.
>
>
>thanks
>Jim MacDonald
>
>_______________________________________________
>List sponsored by Home Power magazine
>
>List Address: RE-wrenches at lists.re-wrenches.org
>
>Options & settings:
>http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org
>
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>http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org
>
>List rules & etiquette:
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>Check out participant bios:
>www.members.re-wrenches.org
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>No virus found in this incoming message.
>Checked by AVG - www.avg.com
>Version: 8.5.455 / Virus Database: 271.1.1/4222 - Release Date: 02/20/12
>19:34:00

Miller Solar
Voice :805-438-5600
email: william at millersolar.com
http://millersolar.com
License No. C-10-773985
Carl Hansen
2012-02-22 21:02:02 UTC
Permalink
Jim,
You can talk with - Solar Converters Inc. - they can probably make a
few of those for you.

Carl Hansen

On 2/22/2012 12:33 PM, Jim MacDonald wrote:
> Hi wrenches
>
> Does anyone know of a decent source where i could buy a converter that pulls 12V or 24v off a battery or load output of a CC and steps it down to 5 Vdc [preferably to a pre-wired USB female connector?]
>
> I am not looking for anything that comes with a module included [like those keychain 1W solar phone chargers], but rather something that will remain hardwired [essentially a USB wall outlet located at the home's indoor DC load center.]
>
> Also NOT looking for the car cigarette lighter adaptor variety, though it will serve the same purpose.
>
> I would like to include these in simple DC-only PV systems for central america, and avoid involving truckstop inverters [going from DC to AC back to DC] to charge cell phones/ mp3 players/ etc.
>
>
> thanks
> Jim MacDonald
>
> _______________________________________________
> List sponsored by Home Power magazine
>
> List Address: RE-wrenches at lists.re-wrenches.org
>
> Options& settings:
> http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org
>
> List-Archive: http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org
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> www.members.re-wrenches.org
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>
>
Steve McCarney
2012-02-22 21:23:10 UTC
Permalink
Hi Jim

Phocos has a 12v to 5v converter with USB output built into their Pico
light. The battery in the light (4 x AA NiMH) can be charged off a 12 v PV
or 12 v battery. They like to sell them with a small module and a few Pico
lights. Maybe you can get just the converter from them?

I just got one of the Pico lights for around the house and it seems like a
solid product so far (2 year warranty). LED with 3 light levels in multi
use fixture that can hang from the ceiling, fit in your hand like a
flashlight or be set down with several adjustable angles makes it
versatile.

Steve McCarney
Project Manager
Solar Electric Light Fund
Colombia

On Wed, Feb 22, 2012 at 2:33 PM, Jim MacDonald <jmac at solaresystems.com>wrote:

> Hi wrenches
>
> Does anyone know of a decent source where i could buy a converter that
> pulls 12V or 24v off a battery or load output of a CC and steps it down to
> 5 Vdc [preferably to a pre-wired USB female connector?]
>
> I am not looking for anything that comes with a module included [like
> those keychain 1W solar phone chargers], but rather something that will
> remain hardwired [essentially a USB wall outlet located at the home's
> indoor DC load center.]
>
> Also NOT looking for the car cigarette lighter adaptor variety, though it
> will serve the same purpose.
>
> I would like to include these in simple DC-only PV systems for central
> america, and avoid involving truckstop inverters [going from DC to AC back
> to DC] to charge cell phones/ mp3 players/ etc.
>
>
> thanks
> Jim MacDonald
>
> _______________________________________________
> List sponsored by Home Power magazine
>
> List Address: RE-wrenches at lists.re-wrenches.org
>
> Options & settings:
> http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org
>
> List-Archive:
> http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org
>
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>
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> www.members.re-wrenches.org
>
>
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R Ray Walters
2012-02-23 03:36:40 UTC
Permalink
http://www.goalzero.com/ has a nice battery/ power pack that has 12 v PV in, 12v and USB power out. I've been shopping for a solar charger to keep my "smart" phone going.

R. Walters
ray at solarray.com
Solar Engineer




On Feb 22, 2012, at 2:23 PM, Steve McCarney wrote:

> Hi Jim
>
> Phocos has a 12v to 5v converter with USB output built into their Pico light. The battery in the light (4 x AA NiMH) can be charged off a 12 v PV or 12 v battery. They like to sell them with a small module and a few Pico lights. Maybe you can get just the converter from them?
>
> I just got one of the Pico lights for around the house and it seems like a solid product so far (2 year warranty). LED with 3 light levels in multi use fixture that can hang from the ceiling, fit in your hand like a flashlight or be set down with several adjustable angles makes it versatile.
>
> Steve McCarney
> Project Manager
> Solar Electric Light Fund
> Colombia
>
> On Wed, Feb 22, 2012 at 2:33 PM, Jim MacDonald <jmac at solaresystems.com> wrote:
> Hi wrenches
>
> Does anyone know of a decent source where i could buy a converter that pulls 12V or 24v off a battery or load output of a CC and steps it down to 5 Vdc [preferably to a pre-wired USB female connector?]
>
> I am not looking for anything that comes with a module included [like those keychain 1W solar phone chargers], but rather something that will remain hardwired [essentially a USB wall outlet located at the home's indoor DC load center.]
>
> Also NOT looking for the car cigarette lighter adaptor variety, though it will serve the same purpose.
>
> I would like to include these in simple DC-only PV systems for central america, and avoid involving truckstop inverters [going from DC to AC back to DC] to charge cell phones/ mp3 players/ etc.
>
>
> thanks
> Jim MacDonald
>
> _______________________________________________
> List sponsored by Home Power magazine
>
> List Address: RE-wrenches at lists.re-wrenches.org
>
> Options & settings:
> http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org
>
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> List sponsored by Home Power magazine
>
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>
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R Ray Walters
2012-02-23 03:36:40 UTC
Permalink
http://www.goalzero.com/ has a nice battery/ power pack that has 12 v PV in, 12v and USB power out. I've been shopping for a solar charger to keep my "smart" phone going.

R. Walters
ray at solarray.com
Solar Engineer




On Feb 22, 2012, at 2:23 PM, Steve McCarney wrote:

> Hi Jim
>
> Phocos has a 12v to 5v converter with USB output built into their Pico light. The battery in the light (4 x AA NiMH) can be charged off a 12 v PV or 12 v battery. They like to sell them with a small module and a few Pico lights. Maybe you can get just the converter from them?
>
> I just got one of the Pico lights for around the house and it seems like a solid product so far (2 year warranty). LED with 3 light levels in multi use fixture that can hang from the ceiling, fit in your hand like a flashlight or be set down with several adjustable angles makes it versatile.
>
> Steve McCarney
> Project Manager
> Solar Electric Light Fund
> Colombia
>
> On Wed, Feb 22, 2012 at 2:33 PM, Jim MacDonald <jmac at solaresystems.com> wrote:
> Hi wrenches
>
> Does anyone know of a decent source where i could buy a converter that pulls 12V or 24v off a battery or load output of a CC and steps it down to 5 Vdc [preferably to a pre-wired USB female connector?]
>
> I am not looking for anything that comes with a module included [like those keychain 1W solar phone chargers], but rather something that will remain hardwired [essentially a USB wall outlet located at the home's indoor DC load center.]
>
> Also NOT looking for the car cigarette lighter adaptor variety, though it will serve the same purpose.
>
> I would like to include these in simple DC-only PV systems for central america, and avoid involving truckstop inverters [going from DC to AC back to DC] to charge cell phones/ mp3 players/ etc.
>
>
> thanks
> Jim MacDonald
>
> _______________________________________________
> List sponsored by Home Power magazine
>
> List Address: RE-wrenches at lists.re-wrenches.org
>
> Options & settings:
> http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org
>
> List-Archive: http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org
>
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> List sponsored by Home Power magazine
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William Miller
2012-02-22 20:02:55 UTC
Permalink
Jim:

Astrodyne makes encapsulated modules that convert Dc to DC. You will need
to build an enclosure with fuses and a little circuit board. I have one in
the field providing 5 VDC and 12 VDC for a broadband internet relay. It
has worked well for years.

Here is a link for one
model:
http://www.astrodyne.com/ecatalog/usa/encapsulated-power-supply/ASD30-24S5

Or you can go the this page and choose your
own: http://www.astrodyne.com/ecatalog/usa/encapsulated-power-supply

Good luck.

William Miller



At 11:33 AM 2/22/2012, you wrote:
>Hi wrenches
>
>Does anyone know of a decent source where i could buy a converter that
>pulls 12V or 24v off a battery or load output of a CC and steps it down to
>5 Vdc [preferably to a pre-wired USB female connector?]
>
>I am not looking for anything that comes with a module included [like
>those keychain 1W solar phone chargers], but rather something that will
>remain hardwired [essentially a USB wall outlet located at the home's
>indoor DC load center.]
>
>Also NOT looking for the car cigarette lighter adaptor variety, though it
>will serve the same purpose.
>
>I would like to include these in simple DC-only PV systems for central
>america, and avoid involving truckstop inverters [going from DC to AC back
>to DC] to charge cell phones/ mp3 players/ etc.
>
>
>thanks
>Jim MacDonald
>
>_______________________________________________
>List sponsored by Home Power magazine
>
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>No virus found in this incoming message.
>Checked by AVG - www.avg.com
>Version: 8.5.455 / Virus Database: 271.1.1/4222 - Release Date: 02/20/12
>19:34:00

Miller Solar
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License No. C-10-773985
Carl Hansen
2012-02-22 21:02:02 UTC
Permalink
Jim,
You can talk with - Solar Converters Inc. - they can probably make a
few of those for you.

Carl Hansen

On 2/22/2012 12:33 PM, Jim MacDonald wrote:
> Hi wrenches
>
> Does anyone know of a decent source where i could buy a converter that pulls 12V or 24v off a battery or load output of a CC and steps it down to 5 Vdc [preferably to a pre-wired USB female connector?]
>
> I am not looking for anything that comes with a module included [like those keychain 1W solar phone chargers], but rather something that will remain hardwired [essentially a USB wall outlet located at the home's indoor DC load center.]
>
> Also NOT looking for the car cigarette lighter adaptor variety, though it will serve the same purpose.
>
> I would like to include these in simple DC-only PV systems for central america, and avoid involving truckstop inverters [going from DC to AC back to DC] to charge cell phones/ mp3 players/ etc.
>
>
> thanks
> Jim MacDonald
>
> _______________________________________________
> List sponsored by Home Power magazine
>
> List Address: RE-wrenches at lists.re-wrenches.org
>
> Options& settings:
> http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org
>
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Steve McCarney
2012-02-22 21:23:10 UTC
Permalink
Hi Jim

Phocos has a 12v to 5v converter with USB output built into their Pico
light. The battery in the light (4 x AA NiMH) can be charged off a 12 v PV
or 12 v battery. They like to sell them with a small module and a few Pico
lights. Maybe you can get just the converter from them?

I just got one of the Pico lights for around the house and it seems like a
solid product so far (2 year warranty). LED with 3 light levels in multi
use fixture that can hang from the ceiling, fit in your hand like a
flashlight or be set down with several adjustable angles makes it
versatile.

Steve McCarney
Project Manager
Solar Electric Light Fund
Colombia

On Wed, Feb 22, 2012 at 2:33 PM, Jim MacDonald <jmac at solaresystems.com>wrote:

> Hi wrenches
>
> Does anyone know of a decent source where i could buy a converter that
> pulls 12V or 24v off a battery or load output of a CC and steps it down to
> 5 Vdc [preferably to a pre-wired USB female connector?]
>
> I am not looking for anything that comes with a module included [like
> those keychain 1W solar phone chargers], but rather something that will
> remain hardwired [essentially a USB wall outlet located at the home's
> indoor DC load center.]
>
> Also NOT looking for the car cigarette lighter adaptor variety, though it
> will serve the same purpose.
>
> I would like to include these in simple DC-only PV systems for central
> america, and avoid involving truckstop inverters [going from DC to AC back
> to DC] to charge cell phones/ mp3 players/ etc.
>
>
> thanks
> Jim MacDonald
>
> _______________________________________________
> List sponsored by Home Power magazine
>
> List Address: RE-wrenches at lists.re-wrenches.org
>
> Options & settings:
> http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org
>
> List-Archive:
> http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org
>
> List rules & etiquette:
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>
> Check out participant bios:
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>
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Jim MacDonald
2012-02-22 19:33:43 UTC
Permalink
Hi wrenches

Does anyone know of a decent source where i could buy a converter that pulls 12V or 24v off a battery or load output of a CC and steps it down to 5 Vdc [preferably to a pre-wired USB female connector?]

I am not looking for anything that comes with a module included [like those keychain 1W solar phone chargers], but rather something that will remain hardwired [essentially a USB wall outlet located at the home's indoor DC load center.]

Also NOT looking for the car cigarette lighter adaptor variety, though it will serve the same purpose.

I would like to include these in simple DC-only PV systems for central america, and avoid involving truckstop inverters [going from DC to AC back to DC] to charge cell phones/ mp3 players/ etc.


thanks
Jim MacDonald
Joel Davidson
2012-02-11 01:03:23 UTC
Permalink
LED teardown at http://www.edn.com/blog/PowerSource/41611-Samsung_LED_light_bulb_teardown_includes_objective_dimming_numbers.php?cid=EDNToday_20120210

----- Original Message -----
From: Jesse Dahl
To: RE-wrenches
Sent: Friday, February 10, 2012 5:32 AM
Subject: Re: [RE-wrenches] 110Vac LED resistance to weak grids in developingworld


I don't know about spikes or grid events, but my home is 3/4 LED and have zero complaints. The warranty on them is a little weak compared to life cycle...... All of mine vary in K rating and lumens and work beautifully.





Sent from my iPhone

On Feb 9, 2012, at 7:45 PM, Ray Walters <ray at solarray.com> wrote:


Personally I love my latest LED lights. They have gotten substantially better just in the past year. We have some 8 watt units in our kitchen that illuminate just like a 35 watt halogen, beautiful color rendition, not that blue they used to have.
I especially like my new 1000 lumen spotlight that lights up brighter than a car head light in a package slightly larger than the old mini mag flash lights.
However, I have no experience with ham radio, or theRF interference issue. We're WiFi, and cell at our house. I do some audio recording, etc. and haven't noticed any extra buzz from the several LEDs I have in my basement studio.

Ray

On 2/9/2012 4:54 PM, toddcory at finestplanet.com wrote:
i have some personal experience with led light bulbs. i put them outside because the cfl floodlights are very s-l-o-w to warm up to full brightness.



1) leds are still slightly less efficient (lumens per watt) than cfl's

2) led light bulbs (2 different brands) throw out an ungodly amount of rfi... want to listen to a conversation on the 2 meter ham radio or listen to a weak fm broadcast station or watch channel 6 on the tee-vee? go shut off the led lights off first.



my conclusion? led light bulbs are not ready for prime time.



todd (still using my 25+ year old phillips dulux cfls)







On Thursday, February 9, 2012 1:44pm, "Jim MacDonald" <jmac at solaresystems.com> said:



Hello wrenches



I am in Central America and looking to suggest customers buy efficient LEDs for illumination in their 120V-wired homes, connected to local power grids with less-than-desirable power quality.



I see that so many manus claim long life for the LEDs, in the tens of thousands of hours, yet so few if any back it up with a decent warranty.


Folks are hesitant to make this investment, believing that voltage surges or dips could destroy the LEDs.



Has anyone heard of LED lights' lives ending prematurely due to grid events?

Would inline surge protectors [something small to be installed immediately downstream of the breaker in the home's main panel) be helpful, and if so, does anyone have any recommended brands?


thanks

Jim MacDonald




Sent from Finest Planet WebMail.



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penobscotsolar
2012-02-10 13:54:26 UTC
Permalink
My home is 100% LED lighting, Kitchler undercounter, non dimmable Philips
Earthlights in closets, dimmable (might help with grid events...) Philips
Earthlights for the rest of the inside lighting and I am very happy with
all of it. Anything from warm white to daylight is available. They are
more expensive, but they are quality lights. The Earthlights are
equivalent to 40 watt and 60 watt incandescents and use 8-12 watts,
depending on the model.

Daryl



> I don't know about spikes or grid events, but my home is 3/4 LED and have
> zero complaints. The warranty on them is a little weak compared to life
> cycle...... All of mine vary in K rating and lumens and work beautifully.
>
>
>
> Sent from my iPhone
>
> On Feb 9, 2012, at 7:45 PM, Ray Walters <ray at solarray.com> wrote:
>
>> Personally I love my latest LED lights. They have gotten substantially
>> better just in the past year. We have some 8 watt units in our kitchen
>> that illuminate just like a 35 watt halogen, beautiful color rendition,
>> not that blue they used to have.
>> I especially like my new 1000 lumen spotlight that lights up brighter
>> than a car head light in a package slightly larger than the old mini mag
>> flash lights.
>> However, I have no experience with ham radio, or theRF interference
>> issue. We're WiFi, and cell at our house. I do some audio recording,
>> etc. and haven't noticed any extra buzz from the several LEDs I have in
>> my basement studio.
>>
>> Ray
>>
>> On 2/9/2012 4:54 PM, toddcory at finestplanet.com wrote:
>>>
>>> i have some personal experience with led light bulbs. i put them
>>> outside because the cfl floodlights are very s-l-o-w to warm up to full
>>> brightness.
>>>
>>> 1) leds are still slightly less efficient (lumens per watt) than cfl's
>>> 2) led light bulbs (2 different brands) throw out an ungodly amount of
>>> rfi... want to listen to a conversation on the 2 meter ham radio or
>>> listen to a weak fm broadcast station or watch channel 6 on the
>>> tee-vee? go shut off the led lights off first.
>>>
>>> my conclusion? led light bulbs are not ready for prime time.
>>>
>>> todd (still using my 25+ year old phillips dulux cfls)
>>>
>>>
>>>
>>> On Thursday, February 9, 2012 1:44pm, "Jim MacDonald"
>>> <jmac at solaresystems.com> said:
>>>
>>> Hello wrenches
>>>
>>> I am in Central America and looking to suggest customers buy efficient
>>> LEDs for illumination in their 120V-wired homes, connected to local
>>> power grids with less-than-desirable power quality.
>>>
>>> I see that so many manus claim long life for the LEDs, in the tens of
>>> thousands of hours, yet so few if any back it up with a decent
>>> warranty.
>>> Folks are hesitant to make this investment, believing that voltage
>>> surges or dips could destroy the LEDs.
>>>
>>> Has anyone heard of LED lights' lives ending prematurely due to grid
>>> events?
>>> Would inline surge protectors [something small to be installed
>>> immediately downstream of the breaker in the home's main panel) be
>>> helpful, and if so, does anyone have any recommended brands?
>>> thanks
>>> Jim MacDonald
>>>
>>>
>>>
>>> Sent from Finest Planet WebMail.
>>>
>>>
>>> _______________________________________________
>>> List sponsored by Home Power magazine
>>>
>>> List Address: RE-wrenches at lists.re-wrenches.org
>>>
>>> Options & settings:
>>> http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org
>>>
>>> List-Archive:
>>> http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org
>>>
>>> List rules & etiquette:
>>> www.re-wrenches.org/etiquette.htm
>>>
>>> Check out participant bios:
>>> www.members.re-wrenches.org
>>>
>> _______________________________________________
>> List sponsored by Home Power magazine
>>
>> List Address: RE-wrenches at lists.re-wrenches.org
>>
>> Options & settings:
>> http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org
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Joel Davidson
2012-02-11 01:03:23 UTC
Permalink
LED teardown at http://www.edn.com/blog/PowerSource/41611-Samsung_LED_light_bulb_teardown_includes_objective_dimming_numbers.php?cid=EDNToday_20120210

----- Original Message -----
From: Jesse Dahl
To: RE-wrenches
Sent: Friday, February 10, 2012 5:32 AM
Subject: Re: [RE-wrenches] 110Vac LED resistance to weak grids in developingworld


I don't know about spikes or grid events, but my home is 3/4 LED and have zero complaints. The warranty on them is a little weak compared to life cycle...... All of mine vary in K rating and lumens and work beautifully.





Sent from my iPhone

On Feb 9, 2012, at 7:45 PM, Ray Walters <ray at solarray.com> wrote:


Personally I love my latest LED lights. They have gotten substantially better just in the past year. We have some 8 watt units in our kitchen that illuminate just like a 35 watt halogen, beautiful color rendition, not that blue they used to have.
I especially like my new 1000 lumen spotlight that lights up brighter than a car head light in a package slightly larger than the old mini mag flash lights.
However, I have no experience with ham radio, or theRF interference issue. We're WiFi, and cell at our house. I do some audio recording, etc. and haven't noticed any extra buzz from the several LEDs I have in my basement studio.

Ray

On 2/9/2012 4:54 PM, toddcory at finestplanet.com wrote:
i have some personal experience with led light bulbs. i put them outside because the cfl floodlights are very s-l-o-w to warm up to full brightness.



1) leds are still slightly less efficient (lumens per watt) than cfl's

2) led light bulbs (2 different brands) throw out an ungodly amount of rfi... want to listen to a conversation on the 2 meter ham radio or listen to a weak fm broadcast station or watch channel 6 on the tee-vee? go shut off the led lights off first.



my conclusion? led light bulbs are not ready for prime time.



todd (still using my 25+ year old phillips dulux cfls)







On Thursday, February 9, 2012 1:44pm, "Jim MacDonald" <jmac at solaresystems.com> said:



Hello wrenches



I am in Central America and looking to suggest customers buy efficient LEDs for illumination in their 120V-wired homes, connected to local power grids with less-than-desirable power quality.



I see that so many manus claim long life for the LEDs, in the tens of thousands of hours, yet so few if any back it up with a decent warranty.


Folks are hesitant to make this investment, believing that voltage surges or dips could destroy the LEDs.



Has anyone heard of LED lights' lives ending prematurely due to grid events?

Would inline surge protectors [something small to be installed immediately downstream of the breaker in the home's main panel) be helpful, and if so, does anyone have any recommended brands?


thanks

Jim MacDonald




Sent from Finest Planet WebMail.



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Jesse Dahl
2012-02-10 13:32:18 UTC
Permalink
I don't know about spikes or grid events, but my home is 3/4 LED and have zero complaints. The warranty on them is a little weak compared to life cycle...... All of mine vary in K rating and lumens and work beautifully.



Sent from my iPhone

On Feb 9, 2012, at 7:45 PM, Ray Walters <ray at solarray.com> wrote:

> Personally I love my latest LED lights. They have gotten substantially better just in the past year. We have some 8 watt units in our kitchen that illuminate just like a 35 watt halogen, beautiful color rendition, not that blue they used to have.
> I especially like my new 1000 lumen spotlight that lights up brighter than a car head light in a package slightly larger than the old mini mag flash lights.
> However, I have no experience with ham radio, or theRF interference issue. We're WiFi, and cell at our house. I do some audio recording, etc. and haven't noticed any extra buzz from the several LEDs I have in my basement studio.
>
> Ray
>
> On 2/9/2012 4:54 PM, toddcory at finestplanet.com wrote:
>>
>> i have some personal experience with led light bulbs. i put them outside because the cfl floodlights are very s-l-o-w to warm up to full brightness.
>>
>> 1) leds are still slightly less efficient (lumens per watt) than cfl's
>> 2) led light bulbs (2 different brands) throw out an ungodly amount of rfi... want to listen to a conversation on the 2 meter ham radio or listen to a weak fm broadcast station or watch channel 6 on the tee-vee? go shut off the led lights off first.
>>
>> my conclusion? led light bulbs are not ready for prime time.
>>
>> todd (still using my 25+ year old phillips dulux cfls)
>>
>>
>>
>> On Thursday, February 9, 2012 1:44pm, "Jim MacDonald" <jmac at solaresystems.com> said:
>>
>> Hello wrenches
>>
>> I am in Central America and looking to suggest customers buy efficient LEDs for illumination in their 120V-wired homes, connected to local power grids with less-than-desirable power quality.
>>
>> I see that so many manus claim long life for the LEDs, in the tens of thousands of hours, yet so few if any back it up with a decent warranty.
>> Folks are hesitant to make this investment, believing that voltage surges or dips could destroy the LEDs.
>>
>> Has anyone heard of LED lights' lives ending prematurely due to grid events?
>> Would inline surge protectors [something small to be installed immediately downstream of the breaker in the home's main panel) be helpful, and if so, does anyone have any recommended brands?
>> thanks
>> Jim MacDonald
>>
>>
>>
>> Sent from Finest Planet WebMail.
>>
>>
>> _______________________________________________
>> List sponsored by Home Power magazine
>>
>> List Address: RE-wrenches at lists.re-wrenches.org
>>
>> Options & settings:
>> http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org
>>
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> _______________________________________________
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Ray Walters
2012-02-10 01:45:02 UTC
Permalink
Personally I love my latest LED lights. They have gotten substantially
better just in the past year. We have some 8 watt units in our kitchen
that illuminate just like a 35 watt halogen, beautiful color rendition,
not that blue they used to have.
I especially like my new 1000 lumen spotlight that lights up brighter
than a car head light in a package slightly larger than the old mini mag
flash lights.
However, I have no experience with ham radio, or theRF interference
issue. We're WiFi, and cell at our house. I do some audio recording,
etc. and haven't noticed any extra buzz from the several LEDs I have in
my basement studio.

Ray

On 2/9/2012 4:54 PM, toddcory at finestplanet.com wrote:
>
> i have some personal experience with led light bulbs. i put them
> outside because the cfl floodlights are very s-l-o-w to warm up to
> full brightness.
>
> 1) leds are still slightly less efficient (lumens per watt) than cfl's
>
> 2) led light bulbs (2 different brands) throw out an ungodly amount of
> rfi... want to listen to a conversation on the 2 meter ham radio or
> listen to a weak fm broadcast station or watch channel 6 on the
> tee-vee? go shut off the led lights off first.
>
> my conclusion? led light bulbs are not ready for prime time.
>
> todd (still using my 25+ year old phillips dulux cfls)
>
> On Thursday, February 9, 2012 1:44pm, "Jim MacDonald"
> <jmac at solaresystems.com> said:
>
> Hello wrenches
>
> I am in Central America and looking to suggest customers buy efficient
> LEDs for illumination in their 120V-wired homes, connected to local
> power grids with less-than-desirable power quality.
>
> I see that so many manus claim long life for the LEDs, in the tens of
> thousands of hours, yet so few if any back it up with a decent warranty.
>
> Folks are hesitant to make this investment, believing that voltage
> surges or dips could destroy the LEDs.
>
> Has anyone heard of LED lights' lives ending prematurely due to grid
> events?
>
> Would inline surge protectors [something small to be installed
> immediately downstream of the breaker in the home's main panel) be
> helpful, and if so, does anyone have any recommended brands?
>
> thanks
>
> Jim MacDonald
>
>
>
>
> Sent from Finest Planet WebMail.
>
>
> _______________________________________________
> List sponsored by Home Power magazine
>
> List Address: RE-wrenches at lists.re-wrenches.org
>
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Jim MacDonald
2012-02-09 21:44:47 UTC
Permalink
Hello wrenches

I am in Central America and looking to suggest customers buy efficient LEDs for illumination in their 120V-wired homes, connected to local power grids with less-than-desirable power quality.

I see that so many manus claim long life for the LEDs, in the tens of thousands of hours, yet so few if any back it up with a decent warranty.

Folks are hesitant to make this investment, believing that voltage surges or dips could destroy the LEDs.

Has anyone heard of LED lights' lives ending prematurely due to grid events?
Would inline surge protectors [something small to be installed immediately downstream of the breaker in the home's main panel) be helpful, and if so, does anyone have any recommended brands?

thanks
Jim MacDonald
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toddcory
2012-02-09 23:54:16 UTC
Permalink
i have some personal experience with led light bulbs. i put them outside because the cfl floodlights are very s-l-o-w to warm up to full brightness.

1) leds are still slightly less efficient (lumens per watt) than cfl's
2) led light bulbs (2 different brands) throw out an ungodly amount of rfi... want to listen to a conversation on the 2 meter ham radio or listen to a weak fm broadcast station or watch channel 6 on the tee-vee? go shut off the led lights off first.

my conclusion? led light bulbs are not ready for prime time.

todd (still using my 25+ year old phillips dulux cfls)



On Thursday, February 9, 2012 1:44pm, "Jim MacDonald" <jmac at solaresystems.com> said:




Hello wrenches

I am in Central America and looking to suggest customers buy efficient LEDs for illumination in their 120V-wired homes, connected to local power grids with less-than-desirable power quality.

I see that so many manus claim long life for the LEDs, in the tens of thousands of hours, yet so few if any back it up with a decent warranty.

Folks are hesitant to make this investment, believing that voltage surges or dips could destroy the LEDs.

Has anyone heard of LED lights' lives ending prematurely due to grid events?
Would inline surge protectors [something small to be installed immediately downstream of the breaker in the home's main panel) be helpful, and if so, does anyone have any recommended brands?

thanks
Jim MacDonald


Sent from Finest Planet WebMail.
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Richard L Ratico
2009-04-28 19:18:13 UTC
Permalink
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Bill Brooks
2009-04-28 19:56:49 UTC
Permalink
25 years is hard on everything. If it is marginal out of the gate, it will
be on fire soon.

Bill.

-----Original Message-----
From: re-wrenches-bounces at lists.re-wrenches.org
[mailto:re-wrenches-bounces at lists.re-wrenches.org] On Behalf Of Richard L
Ratico
Sent: Tuesday, April 28, 2009 12:18 PM
To: re-wrenches at lists.re-wrenches.org
Subject: Re: [RE-wrenches] To Megger or not to Megger

Bill and Matt,

Meggering is hard on insulation. It may, or may not, be hard or harder on PV
cells .... that is the question. Could you guys please elaborate on that?

Dick
Solarwind Electric

P.S. Bill, your recent class here in Vermont was great. Thanks.

---Bill Brooks wrote:
Just to add punctuation to this thread, I always recommend that contractors
megger their arrays, because it has saved my butt several times.
--- end of quote ---

--- Matt Lafferty wrote:
I only meggered the actual arrays on projects where it was a requirement and
I only did that following specific procedures provided by the module
manufacturer. No procedure from the mfr = No array megger.
--- end of quote ---
_______________________________________________
List sponsored by Home Power magazine

List Address: RE-wrenches at lists.re-wrenches.org

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http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org

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John Raynes
2009-04-29 03:00:43 UTC
Permalink
Properly performed, megohm resistance testing is not hard on
insulation, although its close cousin, hi-pot testing, can be.

Insulation resistance testing is usually performed at 100-500 volts
on low voltage (<600V) circuits, 1000 volts on higher voltage
circuits. Just enough voltage to get enough leakage current to
resolve a meaningful resistance value.

The actual dielectric breakdown (failure) voltage for any component
or insulated cable rated for a 600V circuit, will normally be on the
order of 2500 to 5000 volts dc, much higher than insulation
resistance test voltages. The old rule of thumb for hi-pot testing
(which is looking for breakdowns) used to be "2x rated voltage + 1000
volts", which will give you a hi-pot test voltage of about 2500 volts
for a 600V circuit when you consider the peak voltage seen on an AC
circuit. So components that are designed to see test potentials of
2500 volts or so during hi-pot shouldn't have any problem at the
lower megohm resistance potentials.

Insulation resistance measurements will vary widely on the same exact
piece of equipment depending upon relative humidity. Way back when,
I used to do electrical testing in the Middle Atlantic area, which
can see humidity anywhere from 40 to 100%. Insulation resistance
readings that would read >10,000 Megohms in dry conditions could drop
as low as 10 Meghoms in high humidity. If that's the case, more
often than not the leakage is happening across dirty contaminated surfaces.

The general rule that I remember for protecting active circuits from
high test potentials during insulation resistance tests was to short
all of the terminals together on the active side. That could present
practical problems with PV arrays of any size, though, so I'm not
sure what the best practice should be. Megohm testers can't deliver
enough fault current to cause overcurrent-induced damage. But,
depending upon how the test is conducted, it is possible that under
insulation fault conditions, particular cell P-N junctions could see
close to full test voltage and suffer reverse breakdown damage. The
best preventive measure in that case is to use a tester that allows
you to bring the voltage up gradually (and back off if you're seeing a short).

To be picky, only Biddle makes "Meggers". Everybody else makes
megohmeters. Just thought I'd add that in, no extra charge!

John Raynes
RE Solar
Torrey, UT


At 01:56 PM 4/28/2009, you wrote:
>25 years is hard on everything. If it is marginal out of the gate, it will
>be on fire soon.
>
>Bill.
>
>-----Original Message-----
>From: re-wrenches-bounces at lists.re-wrenches.org
>[mailto:re-wrenches-bounces at lists.re-wrenches.org] On Behalf Of Richard L
>Ratico
>Sent: Tuesday, April 28, 2009 12:18 PM
>To: re-wrenches at lists.re-wrenches.org
>Subject: Re: [RE-wrenches] To Megger or not to Megger
>
>Bill and Matt,
>
>Meggering is hard on insulation. It may, or may not, be hard or harder on PV
>cells .... that is the question. Could you guys please elaborate on that?
>
>Dick
>Solarwind Electric
>
>P.S. Bill, your recent class here in Vermont was great. Thanks.
>
>---Bill Brooks wrote:
>Just to add punctuation to this thread, I always recommend that contractors
>megger their arrays, because it has saved my butt several times.
>--- end of quote ---
>
>--- Matt Lafferty wrote:
>I only meggered the actual arrays on projects where it was a requirement and
>I only did that following specific procedures provided by the module
>manufacturer. No procedure from the mfr = No array megger.
>--- end of quote ---
>_______________________________________________
>List sponsored by Home Power magazine
>
>List Address: RE-wrenches at lists.re-wrenches.org
>
>Options & settings:
>http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org
>
>List-Archive:
>http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org
>
>List rules & etiquette:
>www.re-wrenches.org/etiquette.htm
>
>Check out participant bios:
>www.members.re-wrenches.org
>
>_______________________________________________
>List sponsored by Home Power magazine
>
>List Address: RE-wrenches at lists.re-wrenches.org
>
>Options & settings:
>http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org
>
>List-Archive:
>http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org
>
>List rules & etiquette:
>www.re-wrenches.org/etiquette.htm
>
>Check out participant bios:
>www.members.re-wrenches.org
John Raynes
2009-04-29 03:00:43 UTC
Permalink
Properly performed, megohm resistance testing is not hard on
insulation, although its close cousin, hi-pot testing, can be.

Insulation resistance testing is usually performed at 100-500 volts
on low voltage (<600V) circuits, 1000 volts on higher voltage
circuits. Just enough voltage to get enough leakage current to
resolve a meaningful resistance value.

The actual dielectric breakdown (failure) voltage for any component
or insulated cable rated for a 600V circuit, will normally be on the
order of 2500 to 5000 volts dc, much higher than insulation
resistance test voltages. The old rule of thumb for hi-pot testing
(which is looking for breakdowns) used to be "2x rated voltage + 1000
volts", which will give you a hi-pot test voltage of about 2500 volts
for a 600V circuit when you consider the peak voltage seen on an AC
circuit. So components that are designed to see test potentials of
2500 volts or so during hi-pot shouldn't have any problem at the
lower megohm resistance potentials.

Insulation resistance measurements will vary widely on the same exact
piece of equipment depending upon relative humidity. Way back when,
I used to do electrical testing in the Middle Atlantic area, which
can see humidity anywhere from 40 to 100%. Insulation resistance
readings that would read >10,000 Megohms in dry conditions could drop
as low as 10 Meghoms in high humidity. If that's the case, more
often than not the leakage is happening across dirty contaminated surfaces.

The general rule that I remember for protecting active circuits from
high test potentials during insulation resistance tests was to short
all of the terminals together on the active side. That could present
practical problems with PV arrays of any size, though, so I'm not
sure what the best practice should be. Megohm testers can't deliver
enough fault current to cause overcurrent-induced damage. But,
depending upon how the test is conducted, it is possible that under
insulation fault conditions, particular cell P-N junctions could see
close to full test voltage and suffer reverse breakdown damage. The
best preventive measure in that case is to use a tester that allows
you to bring the voltage up gradually (and back off if you're seeing a short).

To be picky, only Biddle makes "Meggers". Everybody else makes
megohmeters. Just thought I'd add that in, no extra charge!

John Raynes
RE Solar
Torrey, UT


At 01:56 PM 4/28/2009, you wrote:
>25 years is hard on everything. If it is marginal out of the gate, it will
>be on fire soon.
>
>Bill.
>
>-----Original Message-----
>From: re-wrenches-bounces at lists.re-wrenches.org
>[mailto:re-wrenches-bounces at lists.re-wrenches.org] On Behalf Of Richard L
>Ratico
>Sent: Tuesday, April 28, 2009 12:18 PM
>To: re-wrenches at lists.re-wrenches.org
>Subject: Re: [RE-wrenches] To Megger or not to Megger
>
>Bill and Matt,
>
>Meggering is hard on insulation. It may, or may not, be hard or harder on PV
>cells .... that is the question. Could you guys please elaborate on that?
>
>Dick
>Solarwind Electric
>
>P.S. Bill, your recent class here in Vermont was great. Thanks.
>
>---Bill Brooks wrote:
>Just to add punctuation to this thread, I always recommend that contractors
>megger their arrays, because it has saved my butt several times.
>--- end of quote ---
>
>--- Matt Lafferty wrote:
>I only meggered the actual arrays on projects where it was a requirement and
>I only did that following specific procedures provided by the module
>manufacturer. No procedure from the mfr = No array megger.
>--- end of quote ---
>_______________________________________________
>List sponsored by Home Power magazine
>
>List Address: RE-wrenches at lists.re-wrenches.org
>
>Options & settings:
>http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org
>
>List-Archive:
>http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org
>
>List rules & etiquette:
>www.re-wrenches.org/etiquette.htm
>
>Check out participant bios:
>www.members.re-wrenches.org
>
>_______________________________________________
>List sponsored by Home Power magazine
>
>List Address: RE-wrenches at lists.re-wrenches.org
>
>Options & settings:
>http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org
>
>List-Archive:
>http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org
>
>List rules & etiquette:
>www.re-wrenches.org/etiquette.htm
>
>Check out participant bios:
>www.members.re-wrenches.org
Bill Brooks
2009-04-28 19:56:49 UTC
Permalink
25 years is hard on everything. If it is marginal out of the gate, it will
be on fire soon.

Bill.

-----Original Message-----
From: re-wrenches-bounces at lists.re-wrenches.org
[mailto:re-wrenches-bounces at lists.re-wrenches.org] On Behalf Of Richard L
Ratico
Sent: Tuesday, April 28, 2009 12:18 PM
To: re-wrenches at lists.re-wrenches.org
Subject: Re: [RE-wrenches] To Megger or not to Megger

Bill and Matt,

Meggering is hard on insulation. It may, or may not, be hard or harder on PV
cells .... that is the question. Could you guys please elaborate on that?

Dick
Solarwind Electric

P.S. Bill, your recent class here in Vermont was great. Thanks.

---Bill Brooks wrote:
Just to add punctuation to this thread, I always recommend that contractors
megger their arrays, because it has saved my butt several times.
--- end of quote ---

--- Matt Lafferty wrote:
I only meggered the actual arrays on projects where it was a requirement and
I only did that following specific procedures provided by the module
manufacturer. No procedure from the mfr = No array megger.
--- end of quote ---
_______________________________________________
List sponsored by Home Power magazine

List Address: RE-wrenches at lists.re-wrenches.org

Options & settings:
http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org

List-Archive:
http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org

List rules & etiquette:
www.re-wrenches.org/etiquette.htm

Check out participant bios:
www.members.re-wrenches.org
Peter Parrish
2009-08-11 16:50:04 UTC
Permalink
We haven't designed/installed a 30 kW-dc class system for some time now
(last time we used a Xantrex PV 30) and are currently investigating what is
available in terms of single inverters with 240V 3Ph output. Our customer
has enough roof space to for 58 kWp of modules, but we have to split the AC
output into two separate services. So the first thing I've noticed is that
there are not many inverters in the 30 kW range: Satcon PowerGate 30,
Xantrex GT30 and by comparison a Sunny Tower with 6ea 6 kW SB inverters.



We will be feeding 240 3P so the GT30 and ST will need transformers.



So, I'm inclined to look more carefully into the PowerGate 30, first.



I am looking for some feedback from folks who have recently installed 30 kW
inverters. If this is contained in an archived thread, please direct me
appropriately.



- Peter



Peter T. Parrish, Ph.D., President
California Solar Engineering, Inc.
820 Cynthia Ave., Los Angeles, CA 90065
CA Lic. 854779, NABCEP Cert. 031806-26
<mailto:peter.parrish at calsolareng.com> peter.parrish at calsolareng.com
Ph 323-258-8883, Mobile 323-839-6108, Fax 323-258-8885




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Jeff Clearwater, Village Power Design
2009-08-11 17:26:47 UTC
Permalink
Hi Peter,

I don't have history with the PV Powered's but
they have a 30 KW I've heard good things about.

A couple of Solectria 15 KWs would make a nice
balance between "single inverter" and redundancy
and ease of install.

2 or 3 Fronius IGPlus 12 KWs would also be a good
solution. Power One (Aurora) also has a 12.5 KW
with multiple channel inputs and other nice
features. Wall mount advantage here too.

And if wall mount is important you don't need the
Tower - just mount 4 or 5 Sunny Boy 7KWs above a
gutter.

Lot's of ways to do it.

Hope that helps!

Best,

Jeff C.





>We haven't designed/installed a 30 kW-dc class
>system for some time now (last time we used a
>Xantrex PV 30) and are currently investigating
>what is available in terms of single inverters
>with 240V 3Ph output. Our customer has enough
>roof space to for 58 kWp of modules, but we have
>to split the AC output into two separate
>services. So the first thing I've noticed is
>that there are not many inverters in the 30 kW
>range: Satcon PowerGate 30, Xantrex GT30 and by
>comparison a Sunny Tower with 6ea 6 kW SB
>inverters.
>
>We will be feeding 240 3P so the GT30 and ST will need transformers.
>
>So, I'm inclined to look more carefully into the PowerGate 30, first.
>
>I am looking for some feedback from folks who
>have recently installed 30 kW inverters. If this
>is contained in an archived thread, please
>direct me appropriately.
>
>- Peter
>
>Peter T. Parrish, Ph.D., President
>California Solar Engineering, Inc.
>820 Cynthia Ave., Los Angeles, CA 90065
>CA Lic. 854779, NABCEP Cert. 031806-26
><mailto:peter.parrish at calsolareng.com>peter.parrish at calsolareng.com
>Ph 323-258-8883, Mobile 323-839-6108, Fax
>323-258-8885
>
>
>The following document was sent as an embedded
>object but not referenced by the email above:
>Attachment converted: Solar Village:image003 54.gif (GIFf/?IC?) (00EACB0C)
>_______________________________________________
>List sponsored by Home Power magazine
>
>List Address: RE-wrenches at lists.re-wrenches.org
>
>Options & settings:
>http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org
>
>List-Archive:
>http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org
>
>List rules & etiquette:
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>
>Check out participant bios:
>www.members.re-wrenches.org


--
~~~~~~~~~~~~~
Jeff Clearwater
Senior Design Engineer
NABCEP (tm) Certified Solar PV Installer
http://www.nabcep.org/
Village Power Design/NorthEast Solar Design
Turnkey Solar Design & Installation for the Commercial Sector
http://www.villagepower.com
gosolar at villagepower.com

Voice: 413-259-3776
Fax: 413-825-0703
65 Schoolhouse Rd
Amherst, MA 01002
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
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Mark Frye
2009-08-11 17:52:27 UTC
Permalink
"we have to split the AC output into two separate services."

How can this be done with a single inverter?

Mark Frye
Berkeley Solar Electric Systems
303 Redbud Way
Nevada City, CA 95959
(530) 401-8024
<http://www.berkeleysolar.com/> www.berkeleysolar.com


_____

From: re-wrenches-bounces at lists.re-wrenches.org
[mailto:re-wrenches-bounces at lists.re-wrenches.org] On Behalf Of Peter
Parrish
Sent: Tuesday, August 11, 2009 9:50 AM
To: 'RE-wrenches'
Subject: [RE-wrenches] 30 kW Inverters



We haven't designed/installed a 30 kW-dc class system for some time now
(last time we used a Xantrex PV 30) and are currently investigating what is
available in terms of single inverters with 240V 3Ph output. Our customer
has enough roof space to for 58 kWp of modules, but we have to split the AC
output into two separate services. So the first thing I've noticed is that
there are not many inverters in the 30 kW range: Satcon PowerGate 30,
Xantrex GT30 and by comparison a Sunny Tower with 6ea 6 kW SB inverters.



We will be feeding 240 3P so the GT30 and ST will need transformers.



So, I'm inclined to look more carefully into the PowerGate 30, first.



I am looking for some feedback from folks who have recently installed 30 kW
inverters. If this is contained in an archived thread, please direct me
appropriately.



- Peter



Peter T. Parrish, Ph.D., President
California Solar Engineering, Inc.
820 Cynthia Ave., Los Angeles, CA 90065
CA Lic. 854779, NABCEP Cert. 031806-26
<mailto:peter.parrish at calsolareng.com> peter.parrish at calsolareng.com
Ph 323-258-8883, Mobile 323-839-6108, Fax 323-258-8885




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Brian Teitelbaum
2009-08-11 21:15:02 UTC
Permalink
Peter,

The Sunny Tower will work at 240VAC three-phase, with no modifications. Since it contains 6 regular SMA Sunny Boy's, they are each configurable for 208, 240, or 277VAC. I don't see any reason why it wouldn't work in a "high leg" configuration also. Another advantage of the Sunny Tower is that it has separate MPPT for each 1/6th of the array. One problem...the Tower at 240VAC is not listed on the CEC list, although the manual clearly states that it is usable at 240V three-phase.

The Xantrex GT30 is not yet available from Xantrex. Latest due date is Sept/Oct. It's a transformer-less design (yea!) with a CEC rating of 96% (at least that is what is advertised)

As per Jeff C's suggestion, two Solectria 15kW units will work fine too, and they are US made. And the Fronius inverters 11.4-3....

PVPowered's 30kW is real sweet and also US made.

And, of course, the Satcon 30.

Enphase?

Too many choices!

Brian Teitelbaum
AEE Solar




From: re-wrenches-bounces at lists.re-wrenches.org [mailto:re-wrenches-bounces at lists.re-wrenches.org] On Behalf Of Peter Parrish
Sent: Tuesday, August 11, 2009 9:50 AM
To: 'RE-wrenches'
Subject: [RE-wrenches] 30 kW Inverters

We haven't designed/installed a 30 kW-dc class system for some time now (last time we used a Xantrex PV 30) and are currently investigating what is available in terms of single inverters with 240V 3Ph output. Our customer has enough roof space to for 58 kWp of modules, but we have to split the AC output into two separate services. So the first thing I've noticed is that there are not many inverters in the 30 kW range: Satcon PowerGate 30, Xantrex GT30 and by comparison a Sunny Tower with 6ea 6 kW SB inverters.

We will be feeding 240 3P so the GT30 and ST will need transformers.

So, I'm inclined to look more carefully into the PowerGate 30, first.

I am looking for some feedback from folks who have recently installed 30 kW inverters. If this is contained in an archived thread, please direct me appropriately.

- Peter

Peter T. Parrish, Ph.D., President
California Solar Engineering, Inc.
820 Cynthia Ave., Los Angeles, CA 90065
CA Lic. 854779, NABCEP Cert. 031806-26
peter.parrish at calsolareng.com<mailto:peter.parrish at calsolareng.com>
Ph 323-258-8883, Mobile 323-839-6108, Fax 323-258-8885


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Jeff Clearwater, Village Power Design
2009-08-11 17:26:47 UTC
Permalink
Hi Peter,

I don't have history with the PV Powered's but
they have a 30 KW I've heard good things about.

A couple of Solectria 15 KWs would make a nice
balance between "single inverter" and redundancy
and ease of install.

2 or 3 Fronius IGPlus 12 KWs would also be a good
solution. Power One (Aurora) also has a 12.5 KW
with multiple channel inputs and other nice
features. Wall mount advantage here too.

And if wall mount is important you don't need the
Tower - just mount 4 or 5 Sunny Boy 7KWs above a
gutter.

Lot's of ways to do it.

Hope that helps!

Best,

Jeff C.





>We haven't designed/installed a 30 kW-dc class
>system for some time now (last time we used a
>Xantrex PV 30) and are currently investigating
>what is available in terms of single inverters
>with 240V 3Ph output. Our customer has enough
>roof space to for 58 kWp of modules, but we have
>to split the AC output into two separate
>services. So the first thing I've noticed is
>that there are not many inverters in the 30 kW
>range: Satcon PowerGate 30, Xantrex GT30 and by
>comparison a Sunny Tower with 6ea 6 kW SB
>inverters.
>
>We will be feeding 240 3P so the GT30 and ST will need transformers.
>
>So, I'm inclined to look more carefully into the PowerGate 30, first.
>
>I am looking for some feedback from folks who
>have recently installed 30 kW inverters. If this
>is contained in an archived thread, please
>direct me appropriately.
>
>- Peter
>
>Peter T. Parrish, Ph.D., President
>California Solar Engineering, Inc.
>820 Cynthia Ave., Los Angeles, CA 90065
>CA Lic. 854779, NABCEP Cert. 031806-26
><mailto:peter.parrish at calsolareng.com>peter.parrish at calsolareng.com
>Ph 323-258-8883, Mobile 323-839-6108, Fax
>323-258-8885
>
>
>The following document was sent as an embedded
>object but not referenced by the email above:
>Attachment converted: Solar Village:image003 54.gif (GIFf/?IC?) (00EACB0C)
>_______________________________________________
>List sponsored by Home Power magazine
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--
~~~~~~~~~~~~~
Jeff Clearwater
Senior Design Engineer
NABCEP (tm) Certified Solar PV Installer
http://www.nabcep.org/
Village Power Design/NorthEast Solar Design
Turnkey Solar Design & Installation for the Commercial Sector
http://www.villagepower.com
gosolar at villagepower.com

Voice: 413-259-3776
Fax: 413-825-0703
65 Schoolhouse Rd
Amherst, MA 01002
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
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Mark Frye
2009-08-11 17:52:27 UTC
Permalink
"we have to split the AC output into two separate services."

How can this be done with a single inverter?

Mark Frye
Berkeley Solar Electric Systems
303 Redbud Way
Nevada City, CA 95959
(530) 401-8024
<http://www.berkeleysolar.com/> www.berkeleysolar.com


_____

From: re-wrenches-bounces at lists.re-wrenches.org
[mailto:re-wrenches-bounces at lists.re-wrenches.org] On Behalf Of Peter
Parrish
Sent: Tuesday, August 11, 2009 9:50 AM
To: 'RE-wrenches'
Subject: [RE-wrenches] 30 kW Inverters



We haven't designed/installed a 30 kW-dc class system for some time now
(last time we used a Xantrex PV 30) and are currently investigating what is
available in terms of single inverters with 240V 3Ph output. Our customer
has enough roof space to for 58 kWp of modules, but we have to split the AC
output into two separate services. So the first thing I've noticed is that
there are not many inverters in the 30 kW range: Satcon PowerGate 30,
Xantrex GT30 and by comparison a Sunny Tower with 6ea 6 kW SB inverters.



We will be feeding 240 3P so the GT30 and ST will need transformers.



So, I'm inclined to look more carefully into the PowerGate 30, first.



I am looking for some feedback from folks who have recently installed 30 kW
inverters. If this is contained in an archived thread, please direct me
appropriately.



- Peter



Peter T. Parrish, Ph.D., President
California Solar Engineering, Inc.
820 Cynthia Ave., Los Angeles, CA 90065
CA Lic. 854779, NABCEP Cert. 031806-26
<mailto:peter.parrish at calsolareng.com> peter.parrish at calsolareng.com
Ph 323-258-8883, Mobile 323-839-6108, Fax 323-258-8885




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Brian Teitelbaum
2009-08-11 21:15:02 UTC
Permalink
Peter,

The Sunny Tower will work at 240VAC three-phase, with no modifications. Since it contains 6 regular SMA Sunny Boy's, they are each configurable for 208, 240, or 277VAC. I don't see any reason why it wouldn't work in a "high leg" configuration also. Another advantage of the Sunny Tower is that it has separate MPPT for each 1/6th of the array. One problem...the Tower at 240VAC is not listed on the CEC list, although the manual clearly states that it is usable at 240V three-phase.

The Xantrex GT30 is not yet available from Xantrex. Latest due date is Sept/Oct. It's a transformer-less design (yea!) with a CEC rating of 96% (at least that is what is advertised)

As per Jeff C's suggestion, two Solectria 15kW units will work fine too, and they are US made. And the Fronius inverters 11.4-3....

PVPowered's 30kW is real sweet and also US made.

And, of course, the Satcon 30.

Enphase?

Too many choices!

Brian Teitelbaum
AEE Solar




From: re-wrenches-bounces at lists.re-wrenches.org [mailto:re-wrenches-bounces at lists.re-wrenches.org] On Behalf Of Peter Parrish
Sent: Tuesday, August 11, 2009 9:50 AM
To: 'RE-wrenches'
Subject: [RE-wrenches] 30 kW Inverters

We haven't designed/installed a 30 kW-dc class system for some time now (last time we used a Xantrex PV 30) and are currently investigating what is available in terms of single inverters with 240V 3Ph output. Our customer has enough roof space to for 58 kWp of modules, but we have to split the AC output into two separate services. So the first thing I've noticed is that there are not many inverters in the 30 kW range: Satcon PowerGate 30, Xantrex GT30 and by comparison a Sunny Tower with 6ea 6 kW SB inverters.

We will be feeding 240 3P so the GT30 and ST will need transformers.

So, I'm inclined to look more carefully into the PowerGate 30, first.

I am looking for some feedback from folks who have recently installed 30 kW inverters. If this is contained in an archived thread, please direct me appropriately.

- Peter

Peter T. Parrish, Ph.D., President
California Solar Engineering, Inc.
820 Cynthia Ave., Los Angeles, CA 90065
CA Lic. 854779, NABCEP Cert. 031806-26
peter.parrish at calsolareng.com<mailto:peter.parrish at calsolareng.com>
Ph 323-258-8883, Mobile 323-839-6108, Fax 323-258-8885


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Peter Parrish
2009-08-11 18:23:55 UTC
Permalink
Can't, that's why we need 2ea inverters with 50 kW on the roof. 25 kW on
each of the two inverters.



Peter T. Parrish, Ph.D., President
California Solar Engineering, Inc.
820 Cynthia Ave., Los Angeles, CA 90065
CA Lic. 854779, NABCEP Cert. 031806-26
<mailto:peter.parrish at calsolareng.com> peter.parrish at calsolareng.com
Ph 323-258-8883, Mobile 323-839-6108, Fax 323-258-8885




_____

From: re-wrenches-bounces at lists.re-wrenches.org
[mailto:re-wrenches-bounces at lists.re-wrenches.org] On Behalf Of Mark Frye
Sent: Tuesday, August 11, 2009 10:52 AM
To: 'RE-wrenches'
Subject: Re: [RE-wrenches] 30 kW Inverters



"we have to split the AC output into two separate services."



How can this be done with a single inverter?


Mark Frye
Berkeley Solar Electric Systems
303 Redbud Way
Nevada City, CA 95959
(530) 401-8024
<http://www.berkeleysolar.com/> www.berkeleysolar.com





_____

From: re-wrenches-bounces at lists.re-wrenches.org
[mailto:re-wrenches-bounces at lists.re-wrenches.org] On Behalf Of Peter
Parrish
Sent: Tuesday, August 11, 2009 9:50 AM
To: 'RE-wrenches'
Subject: [RE-wrenches] 30 kW Inverters

We haven't designed/installed a 30 kW-dc class system for some time now
(last time we used a Xantrex PV 30) and are currently investigating what is
available in terms of single inverters with 240V 3Ph output. Our customer
has enough roof space to for 58 kWp of modules, but we have to split the AC
output into two separate services. So the first thing I've noticed is that
there are not many inverters in the 30 kW range: Satcon PowerGate 30,
Xantrex GT30 and by comparison a Sunny Tower with 6ea 6 kW SB inverters.



We will be feeding 240 3P so the GT30 and ST will need transformers.



So, I'm inclined to look more carefully into the PowerGate 30, first.



I am looking for some feedback from folks who have recently installed 30 kW
inverters. If this is contained in an archived thread, please direct me
appropriately.



- Peter



Peter T. Parrish, Ph.D., President
California Solar Engineering, Inc.
820 Cynthia Ave., Los Angeles, CA 90065
CA Lic. 854779, NABCEP Cert. 031806-26
<mailto:peter.parrish at calsolareng.com> peter.parrish at calsolareng.com
Ph 323-258-8883, Mobile 323-839-6108, Fax 323-258-8885




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Keith Cronin
2009-04-27 21:36:35 UTC
Permalink
Hi

I was wondering, by a show of hands, how many of you megger every project?

Do you have a cut off- like if it is "x" sized system, you will or decide to opt out of performing this task?




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Max Balchowsky
2009-04-27 23:16:11 UTC
Permalink
I haven't used a meggar since I stopped designing traffic signal systems. No ill affects so far ( 20 years now )

Max Balchowsky
SEE Systems




________________________________
From: Keith Cronin <electrichi01 at yahoo.com>
To: RE-Wrenches <re-wrenches at lists.re-wrenches.org>
Sent: Monday, April 27, 2009 2:36:35 PM
Subject: [RE-wrenches] To Megger or not to Megger


Hi

I was wondering, by a show of hands, how many of you megger every project?

Do you have a cut off- like if it is "x" sized system, you will or decide to opt out of performing this task?
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Matt Lafferty
2009-04-28 03:08:28 UTC
Permalink
Hi Keith,

Both hands up here. From day 1 in PV.

Every single field-installed current carrying conductor to the point of
termination. AC & DC. BEFORE energizing them! One megger lead on the
conductor, the other on the raceway or ground-wire. Megger @ 1kV. Must be
greater than 250 Megohms to pass. Record the values on your commissioning
sheet.

I only meggered the actual arrays on projects where it was a requirement and
I only did that following specific procedures provided by the module
manufacturer. No procedure from the mfr = No array megger.

I believe it's a critical thing to do as part of the commissioning. But then
again, I don't like ground faults or fires.

I'll never forget a couple of head scratchers that the megger found.... One
was a perfectly fine, 6' long piece of Orange #12 XHHW-2 that would only
pull 40 Megohms installed in EMT. Pulled it out and replaced it. Inspected
it for any visible flaws. None found. Not a scratch or scuff. Used it as a
training tool for my guys. Hung it on the wall over my desk as a handy
reminder. If anybody wants a picture...

The other was interesting, too. The very first PV system I ever installed.
Was shooting the DC circuits from the inverter all the way to the connector
on the output jumper cables at the modules. Megger showed dead short on one
wire. Fluke 79 on ohms showed clear. Hit it with the megger again. Dead
short. I'm known for being anal about conduit and wire installation, so this
was quite unexpected, not to mention a little embarrassing. This happened to
be a Solarex Millennia Integra system with an Omnion inverter and the array
happened to be scattered all over this roof. For those of you who who have
dealt with that situation, you'll understand what a cluster-*$#! that is...
Especially being my very first PV system and all... I wasn't anywhere near
confident that I had a clue by that point. All ready to see my first install
fire up and this happens.

It was my first install and I had 3 people getting paid prevailing wages to
learn... I was learning too, but I wasn't making anywhere near prevailing
wages, let me tell ya. Well, it was early January, late in the day and foggy
as foggy gets, but we went back onto the roof anyway. Yeah... Overtime for
everybody but me. We opened up the condulets and J-boxes for inspection.
Pulled all the wires up out of the J-boxes. Pulled the endcaps and ground
clips off (unique components of the Integra product). Couldn't find anything
suspicious. Shot it with the megger again, and it was all clear. But no sign
of anything that could have been shorted. We put everything back together
and shot it again. Dead short! Aiyeeeee!

Call it a day. Go home. I couldn't get back to that site until about the
same time the next day. Foggy again. Only took 1 helper with me this time.
We completely repeated the entire exercise, with exactly the same results.
By now, I was pretty sure this solar stuff wasn't my calling. I've always
been regarded as a gifted trouble-shooter and all I could say at this point
was that I didn't know _____! All signs pointed to it being associated with
one of the J-boxes or the endcaps or the ground clips, but there was NOT a
thing we could see. Oh, well. I would have to come back another day. When I
went back, I took the same helper and made sure I had all day if necessary
to fix the problem. No matter what it turned out to be. We planned to take
it apart 1 piece at a time and re-shoot it with the megger after each step.
I left my helper on the ground with the megger while I took it apart on the
roof, 1 screw at a time. Again.

Well, lo and behold, he hollers up that "It's clear" when I pulled the cover
off one of the 2-gang bell boxes. Hadn't moved a wire. Just took the cover
off. Let me tell ya, I stuck my nose and four eyes in that box real close,
but didn't touch any wires. The box was a tight fit with those big,
sealant-filled blue wire nuts that came with the Solarex Kit, but I still
couldn't see anything wierd.

"Shoot it again."

"All clear, boss."

I put the cover back on and installed all the screws. "Shoot it again."

"Dead short." We had a talk later about shouting things like "Dead short" on
the jobsite, but I won't get into all that right now.

I took out one of the cover screws. "Shoot it again." Same answer from the
ground.

I took out a second screw. "Shoot it again." This time the reply was
different. I took out the third screw and we repeated the process. Still
clear. And the fourth. Still clear. WTF? I lifted the cover for what seemed
like the hundredth time. I studied the nested wires, all neatly and
systematically put into what I had thought would be their final resting
place... Days before and time and time again at this point.

I began gently lifting the wires out so they all stood up like dandelions in
a spring lawn. I inspected them for the nth time. Looking for a stray strand
outside its protective hat. Nope. Overtightened wire nut with the spring or
a conductor coming out the tip? Nope. But what's this little, nearly
imperceptible dent in the side of this wire nut? As I looked closer, I could
see that it was round, flat bottomed and about the same diameter as a 6-32
screw. Hmmmm. I rolled the wires back into their resting position. Uh, huh.
This particular wire nut's natural home was directly under the cover screw
which had cleared the fault when removed and the dent lined up perfectly.
The screw could just barely be long enough to pierce the plastic and contact
the wire-spring.

I replaced the wire nut, repositioned the conductors to make sure we
wouldn't have a repeat, and buttoned up the J-box. I put the wirenut in my
pocket for later reference. One more megger shot proved the system to be all
clear. We could now energize the DC and do our Voc & Isc testing prior to
startup. Thank goodness the sun was shining. I wasn't happy about this whole
ordeal, but it was a good thing we caught it with the megger before we put
the power to it.

That wire nut became the first exhibit in what became my collection of
training materials for the "what can go wrong and why we do these
procedures" trainings. Verification that cover and mounting screws cannot
come in contact with energized equipment was officially put in the
checklist. All cover & mounting screws in all types of enclosures. There
would be no exceptions. There would be no excuses. I actually had to write
one guy up for a violation of this at one point. Good thing we caught that
one with the megger before putting the power to it.

I would posit that at least one of the recent PV fires would absolutely have
been prevented if the installer followed the procedure described above. Too
bad most don't. Kudos to those of you who do. It's only a matter of time
until more and more of these AVOIDABLE problems surface.

If you don't have a megger, get one. If you have one, use it! The Fluke 1520
is a nice unit. I recommend it over analog models. I cut my teeth with
analog gear, but really like my 1520. A lot! Rugged instrument that gives
you an actual number to write on your commissioning sheet. In addition to
Megohms, it also does VAC, Lo Ohms, Continuity, has a display backlight,
Lock and Zero functions and my favorite.... Battery Check! Reads out an
actual % value for your battery condition. Nice! Uses 4 "C" cells.

I hope more hands go up on this topic. Thanks for asking, Keith.

Peace and Palm Trees everybody,

Matt Lafferty

_____

From: re-wrenches-bounces at lists.re-wrenches.org
[mailto:re-wrenches-bounces at lists.re-wrenches.org] On Behalf Of Keith Cronin
Sent: Monday, April 27, 2009 2:37 PM
To: RE-Wrenches
Subject: [RE-wrenches] To Megger or not to Megger


Hi

I was wondering, by a show of hands, how many of you megger every project?

Do you have a cut off- like if it is "x" sized system, you will or decide to
opt out of performing this task?


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Jeff Yago
2009-04-28 14:59:04 UTC
Permalink
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Richard L Ratico
2009-04-28 19:18:13 UTC
Permalink
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Peter Parrish
2009-08-11 16:50:04 UTC
Permalink
We haven't designed/installed a 30 kW-dc class system for some time now
(last time we used a Xantrex PV 30) and are currently investigating what is
available in terms of single inverters with 240V 3Ph output. Our customer
has enough roof space to for 58 kWp of modules, but we have to split the AC
output into two separate services. So the first thing I've noticed is that
there are not many inverters in the 30 kW range: Satcon PowerGate 30,
Xantrex GT30 and by comparison a Sunny Tower with 6ea 6 kW SB inverters.



We will be feeding 240 3P so the GT30 and ST will need transformers.



So, I'm inclined to look more carefully into the PowerGate 30, first.



I am looking for some feedback from folks who have recently installed 30 kW
inverters. If this is contained in an archived thread, please direct me
appropriately.



- Peter



Peter T. Parrish, Ph.D., President
California Solar Engineering, Inc.
820 Cynthia Ave., Los Angeles, CA 90065
CA Lic. 854779, NABCEP Cert. 031806-26
<mailto:peter.parrish at calsolareng.com> peter.parrish at calsolareng.com
Ph 323-258-8883, Mobile 323-839-6108, Fax 323-258-8885




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Peter Parrish
2009-08-11 18:23:55 UTC
Permalink
Can't, that's why we need 2ea inverters with 50 kW on the roof. 25 kW on
each of the two inverters.



Peter T. Parrish, Ph.D., President
California Solar Engineering, Inc.
820 Cynthia Ave., Los Angeles, CA 90065
CA Lic. 854779, NABCEP Cert. 031806-26
<mailto:peter.parrish at calsolareng.com> peter.parrish at calsolareng.com
Ph 323-258-8883, Mobile 323-839-6108, Fax 323-258-8885




_____

From: re-wrenches-bounces at lists.re-wrenches.org
[mailto:re-wrenches-bounces at lists.re-wrenches.org] On Behalf Of Mark Frye
Sent: Tuesday, August 11, 2009 10:52 AM
To: 'RE-wrenches'
Subject: Re: [RE-wrenches] 30 kW Inverters



"we have to split the AC output into two separate services."



How can this be done with a single inverter?


Mark Frye
Berkeley Solar Electric Systems
303 Redbud Way
Nevada City, CA 95959
(530) 401-8024
<http://www.berkeleysolar.com/> www.berkeleysolar.com





_____

From: re-wrenches-bounces at lists.re-wrenches.org
[mailto:re-wrenches-bounces at lists.re-wrenches.org] On Behalf Of Peter
Parrish
Sent: Tuesday, August 11, 2009 9:50 AM
To: 'RE-wrenches'
Subject: [RE-wrenches] 30 kW Inverters

We haven't designed/installed a 30 kW-dc class system for some time now
(last time we used a Xantrex PV 30) and are currently investigating what is
available in terms of single inverters with 240V 3Ph output. Our customer
has enough roof space to for 58 kWp of modules, but we have to split the AC
output into two separate services. So the first thing I've noticed is that
there are not many inverters in the 30 kW range: Satcon PowerGate 30,
Xantrex GT30 and by comparison a Sunny Tower with 6ea 6 kW SB inverters.



We will be feeding 240 3P so the GT30 and ST will need transformers.



So, I'm inclined to look more carefully into the PowerGate 30, first.



I am looking for some feedback from folks who have recently installed 30 kW
inverters. If this is contained in an archived thread, please direct me
appropriately.



- Peter



Peter T. Parrish, Ph.D., President
California Solar Engineering, Inc.
820 Cynthia Ave., Los Angeles, CA 90065
CA Lic. 854779, NABCEP Cert. 031806-26
<mailto:peter.parrish at calsolareng.com> peter.parrish at calsolareng.com
Ph 323-258-8883, Mobile 323-839-6108, Fax 323-258-8885




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wes kennedy
2010-01-08 21:41:47 UTC
Permalink
Hi Bill,

I wanted to follow up on your results finding a ground fault with a lower resolution megger.
???
Do you think the .1MOhm meters will work in field applications?

Do you know of any .001MOhm meters like the old 1520?

I have taken a? position with a cadtel mfgr as their field application engineer.? I hope to be using your consulting services if I get over my head.

Thanks and Happy New Year!

-Wes Kennedy

303-653-3073

--- On Tue, 4/28/09, Bill Brooks <billbrooks7 at yahoo.com> wrote:

From: Bill Brooks <billbrooks7 at yahoo.com>
Subject: Re: [RE-wrenches] To Megger or not to Megger
To: "'RE-wrenches'" <re-wrenches at lists.re-wrenches.org>
Date: Tuesday, April 28, 2009, 11:39 AM












Dave,

?

The issue is definitely resolution. The cool thing about the
Fluke 1520 is that it goes down to 0.001MOhms (1000 Ohms). That is the
resolution you are looking for. Neither of the current Flukes go low enough.
That is why I?m going into the field later this week to see how a 0.1MOhm
meter stacks up to finding faults?I have an array with a pesky fault that
should make it fun.

?

Many arrays will ring out as a faulted array when, in fact,
everything is fine. This is especially true of a-Si arrays with low quality
glass. They are very leaky. I?ll keep looking and report back on a
recommendation for Christmas shopping.

?

Just to add punctuation to this thread, I always recommend that
contractors megger their arrays, because it has saved my butt several times.
Also, with exterior wiring systems it is even more important. The problem in
the early days is that people would whine about the $600-$1000 price tag. In my
opinion, that argument is gone. With contractors routinely putting down $1400
for a SunEye, the value of a good megger is similar and costs less.

?

Bill.

?





From:
re-wrenches-bounces at lists.re-wrenches.org
[mailto:re-wrenches-bounces at lists.re-wrenches.org] On Behalf Of David
Palumbo

Sent: Tuesday, April 28, 2009 7:59 AM

To: gilligan06 at gmail.com; 'RE-wrenches'

Subject: Re: [RE-wrenches] To Megger or not to Megger





?

Matt,

?

?Muggering?, I think that will catch on. The last
post, I think, ol? Uncle Bill Brooks (4/13/09 8:17 PM) had on this topic
raised a concern about ?not having enough resolution in the low impedance
area. PV arrays can have an impedance to ground of a slow as 2kOhms. A
resolution of 0.1MOhms will likely not cut it.? Bill went on to say that
he had bought a cheaper meter to test out ?for fun?. ?Some of
us do enjoy ?muggering around?.

?

So my question is. ?Do ?the Fluke 1503?s and
1507?s have enough resolution in the low range?

?

Dave

?





From:
re-wrenches-bounces at lists.re-wrenches.org
[mailto:re-wrenches-bounces at lists.re-wrenches.org] On Behalf Of Matt
Lafferty

Sent: Tuesday, April 28, 2009 9:56 AM

To: 'RE-wrenches'

Subject: Re: [RE-wrenches] To Megger or not to Megger





?

RE: Suggested replacements for Fluke 1520 and "pricey
meters"... Good News below!

?

Another Wrench sent me a note off-list last night, asking how much
a "muggering" would cost. Here's what I?sent him:

?

When I got that 1520 it was?just over?$600. I just
checked online?and?find that it's a discontinued item... Bummer!

?

Fluke recommends the 1587 or the 1507 or the 1503. They also
mention the 1577, but it's an ugly stepsister, or maybe a retarded?adopted
relative, to the 1587.

?

The 1587 is basically a multimeter that also has a <TEST> button to
discharge a high voltage shock into the sample under test... It runs about $620
from standard distributors. http://us.fluke.com/usen/products/Fluke+1587+1577.htm?catalog_name=FlukeUnitedStates? You
can get it for $522 here:

http://www.testequipmentdepot.com/fluke/megohmmeters/1577_87.htm? NOTE: It
does not test at 10A in DMM mode which means it wouldn't be able to test
short-circuit current in strings. Don't bother with the 1577!

?

The 1507 & 1503 are more robust equipment. You can check them
out here: http://us.fluke.com/usen/products/features.htm?cs_id=35391(FlukeProducts)&category=HMA(FlukeProducts)?
While they do measure AC & DC Voltages to 600V as well as some lower ohm
& continuity work, they are really more tailored to being a megger. The
1503 will suffice for most of what I expect you will get into, but there are
some features on the 1507 that might make it worth considering. Mind you, I
haven't looked at at price on either yet, so that last comment may just be
noises coming out my?ass.

?

The 1507 has a Compare function which basically sets up a Pass/Fail
value so you can quickly run through repeated tests. This would be useful for
doing larger systems where you are testing dozens or hundreds of circuits at a
time. For my purposes, I want my guys to think a little more than "Buzz =
OK" and I want them to write an actual tested value down on a piece of
paper so this is not a big plus to me.

?

The 1507 also does Polarization Index and Absorption Ratios. These
are more advanced di-electric tests that you are not likely to need in smaller
scale PV. Use of these features would come into play when playing with real
high-voltage gear or transformers. Might also come into play on super-sensitive
equipment. They might also be used to assess older or aging underground or
overhead feeders.

?

The 1507 & 1503 both have an Earth Bond Resistance function
which is likely to become more of an issue in the future. This feature lets you
test the resistance between a grounding electrode or a grounding electrode
conductor and actual earth. Another use for this feature would be to set the
output to 1kV, connect the alligator jaw to one of Mike Gripando's extremities
and use the probe lead as a tongue depressor while you push <TEST>. This
feature used to be in a single-purpose tester that ran >$2K. They also both
have backlit displays which comes in real handy out in the field.

?

The primary features you want are: 500V & 1kV Test Voltage and
2 Gohms (2,000 Megaohms) or above for the top end of the range. Any of the 3
meet this spec.?

?

Well, I just checked prices for the 1503 & 1507 and I'm
pleasantly surprised. The 1503 ranges from about $291-$370.
Here's the place I found it for $291? http://www.testequipmentdepot.com/fluke/megohmmeters/1503.htm?That's
marked down from the regular price of $342.?

?

The 1507 ranges?from about $385 to $500.?Here's where I found it
for $385... http://www.testequipmentdepot.com/fluke/megohmmeters/1507.htm??That's
a special price, for you only, down from $454.?

?

All things considered if I were in your shoes, I'd go for the 1503.
That give you a solid megger that you can dedicate to that purpose for a
reasonale muggering. If it were me, in Matt's shoes... Oh, what am I saying?
I've already got mine and I just found out I paid too much for it! But I have
Battery Check... Neener neener neener!

?

Be safe out there!

?

Matt Lafferty

?







I hope more hands go up on this topic. Thanks for asking, Keith.

?

Peace and Palm Trees everybody,

?

Matt Lafferty







?






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wes kennedy
2010-01-08 21:41:47 UTC
Permalink
Hi Bill,

I wanted to follow up on your results finding a ground fault with a lower resolution megger.
???
Do you think the .1MOhm meters will work in field applications?

Do you know of any .001MOhm meters like the old 1520?

I have taken a? position with a cadtel mfgr as their field application engineer.? I hope to be using your consulting services if I get over my head.

Thanks and Happy New Year!

-Wes Kennedy

303-653-3073

--- On Tue, 4/28/09, Bill Brooks <billbrooks7 at yahoo.com> wrote:

From: Bill Brooks <billbrooks7 at yahoo.com>
Subject: Re: [RE-wrenches] To Megger or not to Megger
To: "'RE-wrenches'" <re-wrenches at lists.re-wrenches.org>
Date: Tuesday, April 28, 2009, 11:39 AM












Dave,

?

The issue is definitely resolution. The cool thing about the
Fluke 1520 is that it goes down to 0.001MOhms (1000 Ohms). That is the
resolution you are looking for. Neither of the current Flukes go low enough.
That is why I?m going into the field later this week to see how a 0.1MOhm
meter stacks up to finding faults?I have an array with a pesky fault that
should make it fun.

?

Many arrays will ring out as a faulted array when, in fact,
everything is fine. This is especially true of a-Si arrays with low quality
glass. They are very leaky. I?ll keep looking and report back on a
recommendation for Christmas shopping.

?

Just to add punctuation to this thread, I always recommend that
contractors megger their arrays, because it has saved my butt several times.
Also, with exterior wiring systems it is even more important. The problem in
the early days is that people would whine about the $600-$1000 price tag. In my
opinion, that argument is gone. With contractors routinely putting down $1400
for a SunEye, the value of a good megger is similar and costs less.

?

Bill.

?





From:
re-wrenches-bounces at lists.re-wrenches.org
[mailto:re-wrenches-bounces at lists.re-wrenches.org] On Behalf Of David
Palumbo

Sent: Tuesday, April 28, 2009 7:59 AM

To: gilligan06 at gmail.com; 'RE-wrenches'

Subject: Re: [RE-wrenches] To Megger or not to Megger





?

Matt,

?

?Muggering?, I think that will catch on. The last
post, I think, ol? Uncle Bill Brooks (4/13/09 8:17 PM) had on this topic
raised a concern about ?not having enough resolution in the low impedance
area. PV arrays can have an impedance to ground of a slow as 2kOhms. A
resolution of 0.1MOhms will likely not cut it.? Bill went on to say that
he had bought a cheaper meter to test out ?for fun?. ?Some of
us do enjoy ?muggering around?.

?

So my question is. ?Do ?the Fluke 1503?s and
1507?s have enough resolution in the low range?

?

Dave

?





From:
re-wrenches-bounces at lists.re-wrenches.org
[mailto:re-wrenches-bounces at lists.re-wrenches.org] On Behalf Of Matt
Lafferty

Sent: Tuesday, April 28, 2009 9:56 AM

To: 'RE-wrenches'

Subject: Re: [RE-wrenches] To Megger or not to Megger





?

RE: Suggested replacements for Fluke 1520 and "pricey
meters"... Good News below!

?

Another Wrench sent me a note off-list last night, asking how much
a "muggering" would cost. Here's what I?sent him:

?

When I got that 1520 it was?just over?$600. I just
checked online?and?find that it's a discontinued item... Bummer!

?

Fluke recommends the 1587 or the 1507 or the 1503. They also
mention the 1577, but it's an ugly stepsister, or maybe a retarded?adopted
relative, to the 1587.

?

The 1587 is basically a multimeter that also has a <TEST> button to
discharge a high voltage shock into the sample under test... It runs about $620
from standard distributors. http://us.fluke.com/usen/products/Fluke+1587+1577.htm?catalog_name=FlukeUnitedStates? You
can get it for $522 here:

http://www.testequipmentdepot.com/fluke/megohmmeters/1577_87.htm? NOTE: It
does not test at 10A in DMM mode which means it wouldn't be able to test
short-circuit current in strings. Don't bother with the 1577!

?

The 1507 & 1503 are more robust equipment. You can check them
out here: http://us.fluke.com/usen/products/features.htm?cs_id=35391(FlukeProducts)&category=HMA(FlukeProducts)?
While they do measure AC & DC Voltages to 600V as well as some lower ohm
& continuity work, they are really more tailored to being a megger. The
1503 will suffice for most of what I expect you will get into, but there are
some features on the 1507 that might make it worth considering. Mind you, I
haven't looked at at price on either yet, so that last comment may just be
noises coming out my?ass.

?

The 1507 has a Compare function which basically sets up a Pass/Fail
value so you can quickly run through repeated tests. This would be useful for
doing larger systems where you are testing dozens or hundreds of circuits at a
time. For my purposes, I want my guys to think a little more than "Buzz =
OK" and I want them to write an actual tested value down on a piece of
paper so this is not a big plus to me.

?

The 1507 also does Polarization Index and Absorption Ratios. These
are more advanced di-electric tests that you are not likely to need in smaller
scale PV. Use of these features would come into play when playing with real
high-voltage gear or transformers. Might also come into play on super-sensitive
equipment. They might also be used to assess older or aging underground or
overhead feeders.

?

The 1507 & 1503 both have an Earth Bond Resistance function
which is likely to become more of an issue in the future. This feature lets you
test the resistance between a grounding electrode or a grounding electrode
conductor and actual earth. Another use for this feature would be to set the
output to 1kV, connect the alligator jaw to one of Mike Gripando's extremities
and use the probe lead as a tongue depressor while you push <TEST>. This
feature used to be in a single-purpose tester that ran >$2K. They also both
have backlit displays which comes in real handy out in the field.

?

The primary features you want are: 500V & 1kV Test Voltage and
2 Gohms (2,000 Megaohms) or above for the top end of the range. Any of the 3
meet this spec.?

?

Well, I just checked prices for the 1503 & 1507 and I'm
pleasantly surprised. The 1503 ranges from about $291-$370.
Here's the place I found it for $291? http://www.testequipmentdepot.com/fluke/megohmmeters/1503.htm?That's
marked down from the regular price of $342.?

?

The 1507 ranges?from about $385 to $500.?Here's where I found it
for $385... http://www.testequipmentdepot.com/fluke/megohmmeters/1507.htm??That's
a special price, for you only, down from $454.?

?

All things considered if I were in your shoes, I'd go for the 1503.
That give you a solid megger that you can dedicate to that purpose for a
reasonale muggering. If it were me, in Matt's shoes... Oh, what am I saying?
I've already got mine and I just found out I paid too much for it! But I have
Battery Check... Neener neener neener!

?

Be safe out there!

?

Matt Lafferty

?







I hope more hands go up on this topic. Thanks for asking, Keith.

?

Peace and Palm Trees everybody,

?

Matt Lafferty







?






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