[RE-wrenches] Inverter Output Circuit OCPD Meltdown

[Jerry Shafer]

Wrenches
Cant tell anymore but l had a buss failure due to water getting on buss and
pealing the tin off the buss and the aluminum base will light up real quick.
Jerry

On Tue, Jan 21, 2020, 9:10 AM Jason Szumlanski <
jason at floridasolardesigngroup.com> 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
>
>
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