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Hi August,<br><br>
The inverter is an Sunny Boy 7700TL-US-22 with REC 280 TP modules. The
array and roof are grounded. <br><br>
There are large compressors on the system for heat pump and A/C.
The array is on an estimated 2600 sq ft metal roof. The system had no
issues for months after the installation and then the arc fault device
started tripping and wouldn't stay reset. The system was operating
normally again by the time we got there. <br><br>
Drake <br><br>
At 06:16 PM 3/23/2016, you wrote:<br>
<blockquote type=cite class=cite cite="">Hi Drake,<br>
 <br>
What model SMA inverter(s) and modules do you have? We had one case where
a MC4 connector under the array was not making good contact. It was not
seated properly when the installer made up the connector and the arc
fault sensor in the inverter did its job. We had another site where some
electrical noise on the AC side, presumably a sump pump, caused the issue
and we could not solve it so had to switch to another inverter
manufacturer. There were other cases where the impedance or other
electrical characteristics of the solar modules where the likely culprit.
<br>
 <br>
Is your roof and array totally equipment grounded?<br>
 <br>
Best,<br>
 <br>
August<br>
 <br>
<b>From:</b> RE-wrenches
[<a href="mailto:re-wrenches-bounces@lists.re-wrenches.org" eudora="autourl">
mailto:re-wrenches-bounces@lists.re-wrenches.org</a>] <b>On Behalf Of
</b>Drake<br>
<b>Sent:</b> Wednesday, March 23, 2016 2:08 PM<br>
<b>To:</b>
<a href="mailto:RE-wrenches@lists.re-wrenches.org">
RE-wrenches@lists.re-wrenches.org</a><br>
<b>Subject:</b> [RE-wrenches] AFCI trip on metal roof<br>
 <br>
Hello Wrenches, <br><br>
We have a project with an array on a large metal roof. The AFCI has been
tripping. Investigating the system, there is no evidence of any arcing:
the wiring and connections are all very tight. <br><br>
SMA tech support says it is likely that the nuisance tripping comes from
electrical noise getting picked up by the large metal roof. <br><br>
What has been your overall experience with nuisance tripping of arc fault
protection? What were the suspected causes? What was the
solution?<br><br>
Thanks,<br><br>
Drake <br><br>
Drake Chamberlin<br>
<i>Athens Electric LLC<br>
OH License 44810<br>
CO License 3773<br>
NABCEP Certified Solar PV <br>
740-448-7328<br>
</i><a href="http://athens-electric.com/">http://athens-electric.com/</a>
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