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Steve,<br>
<br>
It would be appropriate for the GFDI to have 80-amp rated contacts
that do not have an over-current trip mechanism. IMHO, the fact that
they can trip on over-current and unnecessarily interrupt the dc
system bond is a serious design flaw.<br>
<pre class="moz-signature" cols="72">Kent Osterberg
Blue Mountain Solar, Inc.
<a class="moz-txt-link-abbreviated" href="http://www.bluemountainsolar.com">www.bluemountainsolar.com</a>
</pre>
<br>
On 5/23/2012 9:27 AM, Steve Higgins wrote:
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<div dir="ltr" align="left"><span class="469102016-23052012"><font
color="#0000ff" face="Arial" size="2">Bob,
</font></span></div>
<div dir="ltr" align="left"><span class="469102016-23052012"></span> </div>
<div dir="ltr" align="left"><span class="469102016-23052012"><font
color="#0000ff" face="Arial" size="2">Be careful with that
GFDI... It's most likely wired on the output of the
controllers, on the battery side. </font></span></div>
<div dir="ltr" align="left"><span class="469102016-23052012"></span> </div>
<div dir="ltr" align="left"><span class="469102016-23052012"><font
color="#0000ff" face="Arial" size="2">This can trip if a
ground fault is occurring, or if you are exceeding 80 amps
of current. With 8, 3 module strings, an edge of cloud
event you could have the 80amp portion of that breaker
tripping rather than the GFDI. </font></span></div>
<div dir="ltr" align="left"><span class="469102016-23052012"></span><span
class="469102016-23052012"></span><span
class="469102016-23052012"></span> </div>
<div align="left"><font face="Arial" size="2">
<div align="left"><font face="Arial" size="2">Steve Higgins</font></div>
<div align="left"><font face="Arial" size="2">Sales
Application Engineering Mgr</font></div>
<div align="left"><font face="Arial" size="2">Direct
360-618-4313</font></div>
<div align="left"><font face="Arial" size="2">Outback Power
Technologies </font></div>
<div align="left"><font face="Arial" size="2">5917 195th
Street N<span class="727134612-11072011">E</span>
Arlington, Washington 98223</font></div>
<div align="left"> </div>
</font></div>
<div> </div>
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<div dir="ltr" class="OutlookMessageHeader" align="left"
lang="en-us">
<hr tabindex="-1">
<font face="Tahoma" size="2"><b>From:</b>
<a class="moz-txt-link-abbreviated" href="mailto:re-wrenches-bounces@lists.re-wrenches.org">re-wrenches-bounces@lists.re-wrenches.org</a>
[<a class="moz-txt-link-freetext" href="mailto:re-wrenches-bounces@lists.re-wrenches.org">mailto:re-wrenches-bounces@lists.re-wrenches.org</a>]
<b>On Behalf Of </b>Bob Clark<br>
<b>Sent:</b> Tuesday, May 22, 2012 7:37 PM<br>
<b>To:</b> <a class="moz-txt-link-abbreviated" href="mailto:re-wrenches@lists.re-wrenches.org">re-wrenches@lists.re-wrenches.org</a><br>
<b>Subject:</b> [RE-wrenches] Finding ground faults<br>
</font><br>
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<p class="MsoNormal">Wrenches:<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">Sorry to bring up this situation again, but
I could not find a previous discussion thread that talked
about step-by-step procedures for tracking down ground faults
(I believe it was John Berdner who provided the bulk of the
writing in that regard and it related to high voltage
strings—not that 75-85 volts per string is all that low).<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">We have an Outback FLEXpower Two system
with 8, 3-module strings (Silicon Energy 190W, 25.3Vmp<span
style="FONT-FAMILY: 'TimesNewRoman','serif'; FONT-SIZE: 9pt">,
</span>7.5 Imp) combined in a Midnite Solar MNPV12 combiner
with breakers. The cables from the array are routed to two
different Wiley 4-string pass-through boxes (located under the
two center strings) and then off of the roof and into the PV
combiner.<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">Up until this week the system has seen
several weeks of awesome power production. Yesterday, the
rains came and the GFDI breaker tripped. Every time it rains,
the little green breaker on the GFDI trips off. That tells me
that the ground fault is occurring in a place where at least
one of the conductors on one of the strings (possibly more) is
getting wet and conducting current to ground.<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">It would seem to me that the most likely
place for moisture to cause a ground fault to occur in this
system would be in the pass-through boxes. This would mean
removing the central modules to access the pass-through boxes.<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">Any of you who have mounted the Silicon
Energy modules know that the cables are contained in trays
along the side of the modules until they are routed through
conduit to the pass-through boxes. So, if there is current
going to ground from any of these cables, it could even be
occurring in any of the 9 trays along side of the modules. I
do not like the idea of tracking down a ground fault in one of
these trays as they are all interconnected.<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">How best (and safely) to track down where
the ground fault is occurring? Any advice as to the best and
safest way to track down the ground fault(s) would be greatly
appreciated.<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal"><b><span style="FONT-FAMILY: Papyrus;
COLOR: #e36c0a">Bob Clark<o:p></o:p></span></b></p>
<p class="MsoNormal"><b><i><span style="FONT-FAMILY: Papyrus;
COLOR: #e36c0a">SolarWind Energy Systems, LLC<o:p></o:p></span></i></b></p>
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