[RE-wrenches] AFCI tripping on SB 4000US-12

Tue Jun 20 08:42:00 PDT 2023

Comment below -

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

Martin Herzfeld, Interstate Renewable Energy Council (IREC) Certified
Master Trainer™ Emeritus
California Solar & Electrical Contractor License  #00833782  C-46, C-10,
C-7, C-61 - D-56, D-31
Solar, Electrical, Trenching, Pole Installation & Maintenance,
Instrumentation

Underwriters Laboratories (UL) Certified PV Systems Installer #17, OSHA 30
Certificate
OSHA-Authorized Construction Safety Trainer #32-0106614
CompTIA® Certified Technical Classroom Trainer (CTT+™ Certified)
#T3NSZCNBBKB4QTQG
Solar & Electrical Construction Consultant - 2nd Party Evaluations

International Code Council® (ICC) Certified Residential Electrical
Inspector - E1 #8343181
International Association of Electrical Inspectors (IAEI) Member - #7035507
Electric Vehicle Infrastructure Training Program (EVITP™) Certification
#4039206
Contract Solar (PV) Technical Inspector - 3rd Party Inspections

Certificate - Stanford | Center for Professional Development - Energy
Innovation and Emerging Technologies (EIET)

On Mon, Jun 19, 2023, 11:33 AM August Goers via RE-wrenches <
re-wrenches at lists.re-wrenches.org> wrote:

> Hi William - Is this a TL-21 inverter
> <https://files.sma.de/downloads/SB3-5TL-21-IS-xx-14.pdf?_ga=2.101814081.1325009506.1687199204-2010138759.1678983058>
> line from maybe 8 or 10 years ago? If I recall correctly, that was around
> the time period that SMA was first shipping with AFCI detection - we had a
> few SMA inverters from that vintage producing false AFCI errors. I think
> that long home runs can be part of the issue and the inverter circuitry was
> a little too sensitive. You might try calling SMA to see if there is a
> firmware update or a way to disable AFCI if you feel comfortable
> with disabling that safety feature.
>

Simply, would this be 690.11 and not be a situation of comfort, but "not in
or on buildings,"  "metal(lic) raceways" or other requirements to comply
with the exception?

Separately, we've had a few phantom type AFCI errors on older modules and
> after tons of troubleshooting we think that it might have been internal to
> the modules themselves.
>
> Good luck!
>
> Best, August
>
>
> On Mon, Jun 19, 2023 at 11:11 AM William Miller via RE-wrenches <
> re-wrenches at lists.re-wrenches.org> wrote:
>
>> Friends:
>>
>>
>>
>> We installed a bunch of Shell SQ-150-PC modules on a ground mount almost
>> 20 years ago.  The original SB2500 inverters died so we upgraded to
>> SB4000US-21 inverters.  We had some ground fault or AFCI issues a number of
>> years ago so we replaced all homeruns with PV wire which resolved the
>> problem.
>>
>>
>>
>> These panels have J-boxes which we interconnected with 1/2” NMLT.  The
>> home runs are with PV wire with absolutely no splices and the inter-panel
>> jumpers are THWN.
>>
>>
>>
>> Recently we started getting AFCI disturbances on one inverter.  We
>> isolated the fault to one string.  We opened every pull box and panel J-box
>> and all of the wiring looks dry, clean and tightly connected.  We inspected
>> every panel front and back and see no hotspots or visible corrosion.
>>
>>
>>
>> I have a megger I have never used.  The homerun is kind of long so maybe
>> it has insulation problems.  I could isolate the homerun and megger those
>> leads.  I am researching if I can megger PV modules.  It looks like this is
>> commonly done.  That looks like my next step.
>>
>>
>>
>> Does anyone have any ideas on what I should do next? I suppose I could
>> start swapping each of the 10 modules in the problem string with panels in
>> the non-problem strings, but that seems like a lot of work.
>>
>>
>>
>> Thanks in advance.
>>
>>
>>
>> William Miller
>>
>>
>>
>> Miller Solar
>>
>> 17395 Oak Road, Atascadero, CA 93422
>>
>> 805-438-5600
>>
>> www.millersolar.com
>>
>> CA Lic. 773985
>>
>>
>>
>>
>> _______________________________________________
>> List sponsored by Redwood Alliance
>>
>> Pay optional member dues here: http://re-wrenches.org
>>
>> List Address: RE-wrenches at lists.re-wrenches.org
>>
>> Change listserver email address & settings:
>> http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org
>>
>> There are two list archives for searching. When one doesn't work, try the
>> other:
>> https://www.mail-archive.com/re-wrenches@lists.re-wrenches.org/
>> http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org
>>
>> List rules & etiquette:
>> http://www.re-wrenches.org/etiquette.htm
>>
>> Check out or update participant bios:
>> http://www.members.re-wrenches.org
>>
>> _______________________________________________
> List sponsored by Redwood Alliance
>
> Pay optional member dues here: http://re-wrenches.org
>
> List Address: RE-wrenches at lists.re-wrenches.org
>
> Change listserver email address & settings:
> http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org
>
> There are two list archives for searching. When one doesn't work, try the
> other:
> https://www.mail-archive.com/re-wrenches@lists.re-wrenches.org/
> http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org
>
> List rules & etiquette:
> http://www.re-wrenches.org/etiquette.htm
>
> Check out or update participant bios:
> http://www.members.re-wrenches.org
>
>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org/attachments/20230620/c01bed94/attachment.htm>