Yes - It's only 56A total inverter output rating on a 125A bus. Max string is 13A inverter output rating on 20A OCPD.
On Tue, Jan 21, 2020 at 12:58 PM Chris Sparadeo <[email protected]> wrote: > Jason, > > Have you calculated your back-fed amapacity allowance to confirm it > complies with the 120% busbar rule as per 705.12? > > Best, > Chris > > On Tue, Jan 21, 2020 at 12:40 PM August Goers <[email protected]> wrote: > >> Hi Jason - >> >> It certainly appears that there was some sort of surge or short. We've >> had a few cases where microinverter branch circuit end termination caps >> were left off or fell off and shorted out during rain storms. You might >> want to double check that those are all in place. We've also had cases were >> microinvers themselves developed internal shorts. This third comment is >> only anecdotal - I've been in touch with a couple of other installers that >> have had back-fed breaker issues specifically with Eaton brand breakers >> burning up the bus stabs. Our company has had one unexplained issue where >> the inverter output breaker bus stabs were burned up with Eaton breakers. I >> have no idea whether the breakers were faulty or what, but thought I'd just >> mention it in case there is a pattern. >> >> Best, August >> Luminalt >> >> >> On Tue, Jan 21, 2020 at 9:10 AM Jason Szumlanski < >> [email protected]> wrote: >> >>> (System installed by another contractor...) >>> >>> I have been tasked with assisting in the investigation of damage in a >>> subpanel used to combine inverter output circuits (5 strings of >>> microinverters). There appears to be no damage to conductors or other >>> system components. It looks like the damage started at the stabs of the bus >>> bar where the breakers connect. Picture attached. Here are a few clues: >>> >>> - Monitoring indicates that damage occurred overnight a few weeks >>> ago. That night we had rain as a winter front came through Florida, >>> possibly lightning. The prior day everything was fine. >>> - The next morning, only 2 of 5 strings started producing power, but >>> 4 of 5 strings were reporting data to the Envoy. The two strings that >>> were >>> reporting but not producing power reported 0Vac and Voc on the DC side of >>> the microinverters. >>> - A couple of weeks later, 1 of the 2 strings that was producing >>> power quit doing so, but continued reporting data. >>> - Customer discovered damage yesterday. >>> - About a week before the initial damage apparently manifested >>> itself, another contractor installed a whole house generator transfer >>> switch on the line side of the PV interconnection. The generator has >>> never >>> been run (there is not even a LP fuel source on site yet). I pointed out >>> that the solar interconnection, which was previously on the supply side, >>> would need to be moved to the supply side of the generator transfer >>> switch's main breaker before operation. During the transfer switch >>> installation, the contractor also switched line 1 and line 2, but that >>> shouldn't really matter, except for Enphase consumption monitoring, which >>> was messed up by the swapping of the lines. >>> >>> So I'm looking for ideas. I'm wondering if the OCPD would be a likely >>> place for lightning damage to manifest itself. I can't visually detect any >>> other damage anywhere else. I can't imagine that the transfer switch >>> installation would have anything to do with it, but the timing is >>> interesting. Other than replacing the subpanel and OCPD and firing it back >>> up (no pun intended), I'm not sure how to approach further investigation. >>> >>> Jason Szumlanski >>> Florida Solar Design Group >>> >>> >>> _______________________________________________ >>> List sponsored by Redwood Alliance >>> >>> List Address: [email protected] >>> >>> Change listserver email address & settings: >>> http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org >>> >>> List-Archive: >>> http://www.mail-archive.com/[email protected]/maillist.html >>> >>> List rules & etiquette: >>> www.re-wrenches.org/etiquette.htm >>> >>> Check out or update participant bios: >>> www.members.re-wrenches.org >>> >>> _______________________________________________ >> List sponsored by Redwood Alliance >> >> List Address: [email protected] >> >> Change listserver email address & settings: >> http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org >> >> List-Archive: >> http://www.mail-archive.com/[email protected]/maillist.html >> >> List rules & etiquette: >> www.re-wrenches.org/etiquette.htm >> >> Check out or update participant bios: >> www.members.re-wrenches.org >> >> > > -- > Chris Sparadeo > > > C_802-369-4458 > H_802-728-3059 > _______________________________________________ > List sponsored by Redwood Alliance > > List Address: [email protected] > > Change listserver email address & settings: > http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org > > List-Archive: > http://www.mail-archive.com/[email protected]/maillist.html > > List rules & etiquette: > www.re-wrenches.org/etiquette.htm > > Check out or update participant bios: > www.members.re-wrenches.org > >
_______________________________________________ List sponsored by Redwood Alliance List Address: [email protected] Change listserver email address & settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://www.mail-archive.com/[email protected]/maillist.html List rules & etiquette: www.re-wrenches.org/etiquette.htm Check out or update participant bios: www.members.re-wrenches.org
