<div dir="ltr">It's fortunate that you have two charge controllers, which makes troubleshooting easier. If there is a solid ground fault, it should be easy to track down. Assuming that it is intermittent, you can start to do things like swap which PV input goes to which charge controller. Then see if the fault stays with the charge controller or if it switches to the other one, which will tell you if the issue is with the PV or with that charge controller itself. If its in the PV, then you can swap strings around until you can figure out which one has the fault. Also, as Mac mentioned, a visual inspection of the array may give a quick answer.<div><br></div><div>Cheers,</div><div>Dave</div></div><br><div class="gmail_quote"><div dir="ltr" class="gmail_attr">On Sun, Jan 19, 2025 at 3:29 PM jay via RE-wrenches <<a href="mailto:re-wrenches@lists.re-wrenches.org" target="_blank">re-wrenches@lists.re-wrenches.org</a>> wrote:<br></div><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex"><div>HI Kent,<div><br></div><div>Thanks for that info. </div><div>Makes sense</div><div><br></div><div>jay<br id="m_941585141441672574m_6592747131199106495lineBreakAtBeginningOfMessage"><div><br><blockquote type="cite"><div>On Jan 19, 2025, at 12:47 PM, Kent via RE-wrenches <<a href="mailto:re-wrenches@lists.re-wrenches.org" target="_blank">re-wrenches@lists.re-wrenches.org</a>> wrote:</div><br><div>
<div>
Jay,<br>
<br>
If there is a PV ground fault, putting a short across the fuse
holder may cause damage by drawing an arc. Use a multimeter to
measure voltage across the fuse holder (should be the same as
measuring voltage between PV negative and ground); if there is no
voltage then there probably isn't a PV ground fault or any ground
fault at that time. If there is voltage, then you need to track it
down. It isn't necessarily in the PV array - it could be a dc load
or even in the battery. If the voltage exceeds the battery voltage,
the PV array is the culprit. If you compute the proportion of the
negative to ground voltage to open circuit voltage then apply that
proportion to the number of modules, it should tell you about where
to look. If you have multiple strings, isolate the problem:
disconnect all of the PV negative connections and see which one
gives you a solid voltage to ground. <br>
<br>
Kent Osterberg<br>
Blue Mountain Solar <br><p><br>
</p>
<div>On 1/19/2025 6:57 AM, Jay via
RE-wrenches wrote:<br>
</div>
<blockquote type="cite">
<div dir="ltr">Question about the fuses. </div>
<div dir="ltr"><br>
</div>
<div dir="ltr">For testing could you put a short test wire across
the ends of the fuse holder and use a clamp on to test for
current? Would it cause any damage?</div>
<div dir="ltr"><br>
</div>
<div dir="ltr">Instead of potentially going through lots of fuses?
</div>
<div dir="ltr"><br>
</div>
<div dir="ltr">Jay</div>
<div dir="ltr"><br>
</div>
<div dir="ltr"><br>
</div>
<div dir="ltr"><br>
<blockquote type="cite">On Jan 19, 2025, at 7:48 AM, Mac Lewis
via RE-wrenches <a href="mailto:re-wrenches@lists.re-wrenches.org" target="_blank"><re-wrenches@lists.re-wrenches.org></a>
wrote:<br>
<br>
</blockquote>
</div>
<blockquote type="cite">
<div dir="ltr">
<div dir="ltr">Hello Dana,<br>
<div><br>
</div>
<div>Ground faults are tricky. Here is how I would tackle
this on a sunny day:</div>
<div>1. Visual inspection of array, looking for backsheet,
wire damage, broken glass, critter stuff (nests and bite
marks). Look for water intrusion or evidence that water
has been somewhere that it shouldn't.</div>
<div>2. Visual inspection of all splice boxes, checking for
wire insulation damage, evidence of water intrusion and
critter entry.</div>
<div>3. Probe voltage between +, - and Ground (do this at a
string level initially, and isolate strings and do this at
open circuit). Any evidence of bouncing voltage readings,
loss of voltage, not rock solid voltage suggests you may
have a ground fault in that string. If its in the string
somewhere, you may see the voltage bounce and read in some
fraction of the string voltage. This can tell you where
in the string it may be. FOr example, if you have a 5
module string, you may get a 3/5 voltage reading if the
fault is near the 3rd module.</div>
<div>4. Turn off array at combiner and run continuity tests
between +, - and Ground again (no gfp fuse). If you have
continuity, this may suggest a ground fault in conduit run
between combiner and FM100.</div>
<div><br>
</div>
<div>Good Luck, bring extra fuses!</div>
</div>
<br>
<div class="gmail_quote">
<div dir="ltr" class="gmail_attr">On Sun, Jan 19, 2025 at
7:07 AM Dana Orzel via RE-wrenches <<a href="mailto:re-wrenches@lists.re-wrenches.org" target="_blank">re-wrenches@lists.re-wrenches.org</a>>
wrote:<br>
</div>
<blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex">
<div dir="auto">
Yes I have 2 FM100s<br id="m_941585141441672574m_6592747131199106495m_-2975783510821813743lineBreakAtBeginningOfSignature">
<div dir="ltr">Dana Orzel
<div>C: 208.721.7003
<div>E- <a href="mailto:dana@solarwork.com" target="_blank">dana@solarwork.com</a></div>
</div>
</div>
<div dir="ltr"><br>
<blockquote type="cite">On Jan 18, 2025, at 7:08 PM,
Kirpal Khalsa via RE-wrenches <<a href="mailto:re-wrenches@lists.re-wrenches.org" target="_blank">re-wrenches@lists.re-wrenches.org</a>>
wrote:<br>
<br>
</blockquote>
</div>
<blockquote type="cite">
<div dir="ltr">
<div dir="auto">Dana...
<div dir="auto">Do you have multiple FM 100s? If
so only one should have the GFI fuse. </div>
<div dir="auto">Broken panel with water getting
into glass?</div>
<div dir="auto">Turn it off and wait 5 min and
turn it on. Usually clears it especially if
it's a faulty nuisance trip. </div>
<div dir="auto">Have had numerous FM 100s give
faulty afci errors. Removing the.afci boards
always resolved this issue. But of course check
all you connections leading to and from the cc.</div>
<div dir="auto">Keep a few extra 1A gfi fuses
handy....you may need a couple to test it all
out. </div>
<div dir="auto">Keep us posted. </div>
<div dir="auto">Good luck</div>
<div dir="auto">Kirpal</div>
<div dir="auto"><br>
</div>
</div>
<br>
<div class="gmail_quote">
<div dir="ltr" class="gmail_attr">On Sat, Jan 18,
2025, 2:40 PM Dana Orzel via RE-wrenches <<a href="mailto:re-wrenches@lists.re-wrenches.org" target="_blank">re-wrenches@lists.re-wrenches.org</a>>
wrote:<br>
</div>
<blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex">
Hey, all you wise ones,<br>
37 years in the business and I’ve never had a
ground fault ever in any installation I’ve done
or my home systems. I went out to my system here
an hour ago and one FM 100 is completely turned
off claiming ground fault on the mate 3S.<br>
I guess my first question is :<br>
<br>
Is this really a ground fault ?<br>
<br>
I had removed the ground fault breaker when I
upgraded due to space considerations<br>
<br>
In my entire time in this business, I’ve never
had to deal with the ground fault any
suggestions on how I should be tracing this?<br>
<br>
Has anybody seen this in an FM 100 when it
wasn’t a ground fault?<br>
<br>
I do own a megger& I’ve never had to use
it. I only bought it about three months ago
cause it seemed like a good idea and I might
need to use one someday, Maybe I’m psychic ?<br>
now if I could just figure out how to trace this
out.<br>
All suggestions welcome thanks all!<br>
<br>
Dana Orzel<br>
C: 208.721.7003<br>
E- <a href="mailto:dana@solarwork.com" rel="noreferrer" target="_blank">dana@solarwork.com</a><br>
_______________________________________________<br>
</blockquote>
</div>
</div>
</blockquote>
</div>
<br>
</blockquote>
</div>
<span></span><span style="white-space:pre-wrap">
</span></div>
</blockquote>
</blockquote>
</div>
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