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<p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";
color:#1F497D'>What are the options to the Fluke 1520? Also what are good
sources for purchasing these pricey meters?<o:p></o:p></span></p>
<p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";
color:#1F497D'><o:p> </o:p></span></p>
<p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";
color:#1F497D'>Dave<o:p></o:p></span></p>
<p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";
color:#1F497D'><o:p> </o:p></span></p>
<div style='border:none;border-top:solid #B5C4DF 1.0pt;padding:3.0pt 0in 0in 0in'>
<p class=MsoNormal><b><span style='font-size:10.0pt;font-family:"Tahoma","sans-serif"'>From:</span></b><span
style='font-size:10.0pt;font-family:"Tahoma","sans-serif"'>
re-wrenches-bounces@lists.re-wrenches.org
[mailto:re-wrenches-bounces@lists.re-wrenches.org] <b>On Behalf Of </b>robert
ellison<br>
<b>Sent:</b> Tuesday, April 28, 2009 6:24 AM<br>
<b>To:</b> RE-wrenches<br>
<b>Subject:</b> Re: [RE-wrenches] To Megger or not to Megger<o:p></o:p></span></p>
</div>
<p class=MsoNormal><o:p> </o:p></p>
<div>
<p class=MsoNormal>Just went to check the Fluke 1520 price. Looks like it is
discontinued.<o:p></o:p></p>
</div>
<div>
<p class=MsoNormal>They do have a couple suggested replacements.<o:p></o:p></p>
</div>
<div>
<p class=MsoNormal> <o:p></o:p></p>
</div>
<div>
<p class=MsoNormal>Just for reference,<o:p></o:p></p>
</div>
<div>
<p class=MsoNormal style='margin-bottom:12.0pt'>Bob<o:p></o:p></p>
</div>
<div>
<p class=MsoNormal>On Mon, Apr 27, 2009 at 11:08 PM, Matt Lafferty <<a
href="mailto:gilligan06@gmail.com">gilligan06@gmail.com</a>> wrote:<o:p></o:p></p>
<div>
<p class=MsoNormal><span style='font-size:10.0pt;font-family:"Arial","sans-serif";
color:blue'>Hi Keith,</span><o:p></o:p></p>
<p class=MsoNormal> <o:p></o:p></p>
<p class=MsoNormal><span style='font-size:10.0pt;font-family:"Arial","sans-serif";
color:blue'>Both hands up here. From day 1 in PV.</span><o:p></o:p></p>
<p class=MsoNormal> <o:p></o:p></p>
<p class=MsoNormal><span style='font-size:10.0pt;font-family:"Arial","sans-serif";
color:blue'>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.</span><o:p></o:p></p>
<p class=MsoNormal> <o:p></o:p></p>
<p class=MsoNormal><span style='font-size:10.0pt;font-family:"Arial","sans-serif";
color:blue'>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.</span><o:p></o:p></p>
<p class=MsoNormal> <o:p></o:p></p>
<p class=MsoNormal><span style='font-size:10.0pt;font-family:"Arial","sans-serif";
color:blue'>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.</span><o:p></o:p></p>
<p class=MsoNormal> <o:p></o:p></p>
<p class=MsoNormal><span style='font-size:10.0pt;font-family:"Arial","sans-serif";
color:blue'>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...</span><o:p></o:p></p>
<p class=MsoNormal> <o:p></o:p></p>
<p class=MsoNormal><span style='font-size:10.0pt;font-family:"Arial","sans-serif";
color:blue'>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.</span><o:p></o:p></p>
<p class=MsoNormal> <o:p></o:p></p>
<p class=MsoNormal><span style='font-size:10.0pt;font-family:"Arial","sans-serif";
color:blue'>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 <em><span style='font-family:"Arial","sans-serif"'>(unique
components of the Integra product)</span></em>. 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!</span><o:p></o:p></p>
<p class=MsoNormal> <o:p></o:p></p>
<p class=MsoNormal><span style='font-size:10.0pt;font-family:"Arial","sans-serif";
color:blue'>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.</span><o:p></o:p></p>
<p class=MsoNormal> <o:p></o:p></p>
<p class=MsoNormal><span style='font-size:10.0pt;font-family:"Arial","sans-serif";
color:blue'>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.</span><o:p></o:p></p>
<p class=MsoNormal> <o:p></o:p></p>
<p class=MsoNormal><span style='font-size:10.0pt;font-family:"Arial","sans-serif";
color:blue'>"Shoot it again."</span><o:p></o:p></p>
<p class=MsoNormal> <o:p></o:p></p>
<p class=MsoNormal><span style='font-size:10.0pt;font-family:"Arial","sans-serif";
color:blue'>"All clear, boss."</span><o:p></o:p></p>
<p class=MsoNormal> <o:p></o:p></p>
<p class=MsoNormal><span style='font-size:10.0pt;font-family:"Arial","sans-serif";
color:blue'>I put the cover back on and installed all the screws. "Shoot
it again."</span><o:p></o:p></p>
<p class=MsoNormal> <o:p></o:p></p>
<p class=MsoNormal><span style='font-size:10.0pt;font-family:"Arial","sans-serif";
color:blue'>"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.</span><o:p></o:p></p>
<p class=MsoNormal> <o:p></o:p></p>
<p class=MsoNormal><span style='font-size:10.0pt;font-family:"Arial","sans-serif";
color:blue'>I took out one of the cover screws. "Shoot it again."
Same answer from the ground.</span><o:p></o:p></p>
<p class=MsoNormal> <o:p></o:p></p>
<p class=MsoNormal><span style='font-size:10.0pt;font-family:"Arial","sans-serif";
color:blue'>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. </span><o:p></o:p></p>
<p class=MsoNormal> <o:p></o:p></p>
<p class=MsoNormal><span style='font-size:10.0pt;font-family:"Arial","sans-serif";
color:blue'>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.
</span><o:p></o:p></p>
<p class=MsoNormal> <o:p></o:p></p>
<p class=MsoNormal><span style='font-size:10.0pt;font-family:"Arial","sans-serif";
color:blue'>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.</span><o:p></o:p></p>
<p class=MsoNormal> <o:p></o:p></p>
<p class=MsoNormal><span style='font-size:10.0pt;font-family:"Arial","sans-serif";
color:blue'>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. <strong><u><span style='font-family:"Arial","sans-serif"'>All</span></u></strong><strong><span
style='font-family:"Arial","sans-serif"'> </span></strong>cover &
mounting screws in <strong><u><span style='font-family:"Arial","sans-serif"'>all</span></u></strong>
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.</span><o:p></o:p></p>
<p class=MsoNormal> <o:p></o:p></p>
<p class=MsoNormal><span style='font-size:10.0pt;font-family:"Arial","sans-serif";
color:blue'>I would posit that at least one of the recent PV fires would <strong><u><span
style='font-family:"Arial","sans-serif"'>absolutely have been prevented</span></u></strong>
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.</span><o:p></o:p></p>
<p class=MsoNormal> <o:p></o:p></p>
<p class=MsoNormal><span style='font-size:10.0pt;font-family:"Arial","sans-serif";
color:blue'>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.</span><o:p></o:p></p>
<p class=MsoNormal> <o:p></o:p></p>
<p class=MsoNormal><span style='font-size:10.0pt;font-family:"Arial","sans-serif";
color:blue'>I hope more hands go up on this topic. Thanks for asking, Keith.</span><o:p></o:p></p>
<p class=MsoNormal> <o:p></o:p></p>
<p class=MsoNormal><span style='font-size:10.0pt;font-family:"Arial","sans-serif";
color:blue'>Peace and Palm Trees everybody,</span><o:p></o:p></p>
<p class=MsoNormal> <o:p></o:p></p>
<p class=MsoNormal><span style='font-size:10.0pt;font-family:"Arial","sans-serif";
color:blue'>Matt Lafferty</span><o:p></o:p></p>
<div>
<p class=MsoNormal> <o:p></o:p></p>
</div>
<div class=MsoNormal align=center style='text-align:center'>
<hr size=2 width="100%" align=center>
</div>
<p class=MsoNormal><b><span style='font-size:10.0pt;font-family:"Tahoma","sans-serif"'>From:</span></b><span
style='font-size:10.0pt;font-family:"Tahoma","sans-serif"'> <a
href="mailto:re-wrenches-bounces@lists.re-wrenches.org" target="_blank">re-wrenches-bounces@lists.re-wrenches.org</a>
[mailto:<a href="mailto:re-wrenches-bounces@lists.re-wrenches.org"
target="_blank">re-wrenches-bounces@lists.re-wrenches.org</a>] <b>On Behalf Of </b>Keith
Cronin<br>
<b>Sent:</b> Monday, April 27, 2009 2:37 PM<br>
<b>To:</b> RE-Wrenches <o:p></o:p></span></p>
<div>
<p class=MsoNormal><span style='font-size:10.0pt;font-family:"Tahoma","sans-serif"'><br>
<b>Subject:</b> [RE-wrenches] To Megger or not to Megger<o:p></o:p></span></p>
</div>
<p class=MsoNormal><o:p> </o:p></p>
<div>
<div>
<div>
<p class=MsoNormal>Hi<br>
<br>
I was wondering, by a show of hands, how many of you megger every project?<br>
<br>
Do you have a cut off- like if it is "x" sized system, you will or
decide to opt out of performing this task?<o:p></o:p></p>
</div>
</div>
<p class=MsoNormal><o:p> </o:p></p>
</div>
</div>
<p class=MsoNormal style='margin-bottom:12.0pt'><br>
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