[RE-wrenches] Enphase String Breaker Heating Up

[Jerry Shafer]

Jason
Is the installation designed for 208 as you have greater limitations then
240, so now replace the buss and all the breakers, after that run currents
tests and see what you have. I had a 3 phase that the tin cam off the buss
and looked like a plazma cutter due to the exposed aluminum
Fun times

On Thu, Aug 4, 2022, 11:12 AM Jason Szumlanski via RE-wrenches <
re-wrenches at lists.re-wrenches.org> wrote:

> I have a commercial 208 volt job where four of 11 fully populated strings
> of IQ7A had breakers that were tripped as reported by the client. They were
> able to reset two of them. They also reported that the two they were not
> able to reset we're very hot. The other two were warm.  By the time I got
> to the site, all four breakers had permanently failed.
>
> Once I got replacements, I was able to install them and they turned on
> without any faults. I gave it about 15 minutes and then put my infrared
> camera on it. To my surprise, the breaker immediately above two of the
> failed breakers and across from the other two failed breakers was clearly
> hot. I'm thinking this might have been the bad breaker all along causing
> the heat issue on the bus bar which made adjacent breakers fail. But this
> hot breaker did not fail.
>
> Does this seem like a plausible scenario, and if so, any ideas on what
> might have caused it? All of the breaker bolts were tight, but a couple
> were not torqued to spec. I just find it strange that one breaker that
> didn't fail would cause other adjacent breakers to heat up enough to fail.
>
> Flir image attached. This was after I replaced the four failed breakers.
>
> Jason Szumlanski
> Florida Solar Design Group
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