[RE-wrenches] Enphase intermittent breaker trippjng

[Chad Waits]

Hey Jason,

We have experienced this on multiple systems over the past 2 years. We have
one system where 1 inverter pops an entire sub offline that has 72 other
inverters in it (screenshots attached). The only way we have been able to
isolate the problem inverter(s) is to start first with isolating circuits,
and then unplugging individual inverters until the culprit is found. We've
had multiple cases escalated to top engineers and we have yet to get an
explanation of what is going on. Obviously something in the bad inverter(s)
is creating a catastrophic short but what is causing that has not been
revealed to us.

[image: Screen Shot 2020-05-21 at 7.10.24 AM.png]
[image: Screen Shot 2020-05-21 at 7.09.59 AM.png]

I'd appreciate anything you may find out in your investigations.

Thanks!

Chad Waits
President-Net Zero Solar
Cell: (520) 270-4873



On Thu, May 21, 2020 at 6:57 AM Jason Szumlanski <
jason at floridasolardesigngroup.com> wrote:

> I'm trying to resolve an intermittent frustrating problem with and Enphase
> IQ system. There are three AC Branch circuits of 9 microinverters each
> coming into an Enphase AC combiner.
>
> What has been happening is one of the BR220 branch circuit breakers and
> the combine CH240 breaker in the main backfed load center have been
> tripping simultaneously. It has happened about four times in the last 6
> months. It was always the same branch circuit breaker, so we kept
> investigating that string, checking the junction box, trunk cable, and cap,
> etc. Finally we swapped out the BR220 breaker.
>
> Fast forward 4 weeks, and we got another call. This time a different
> branch circuit breaker and the main breaker tripped simultaneously. We
> checked that branch circuit and could not find any fault. It seems unlikely
> that two branch circuit breakers would be faulty, so we have now switched
> out the CH240 main breaker in hopes that it is the culprit.
>
> I'm not totally confident in this resolution and I have my fingers
> crossed. If that doesn't work, does anyone have any suggestions on another
> diagnostic step? These intermittent problems are a major hassle. One
> thought I had was to switch to a supply side interconnection with a fusible
> disconnect. Maybe the intermittent fault would blow one of the two line
> fuses so at least I could narrow it down to which line the fault is on if
> there is in fact a fault.
>
> I have experienced two other tripping breaker issues with Enphase systems
> in the past. Neither of them were systems I installed. One turned out to be
> branch circuits that were not properly paired up and landed on different
> breakers. Another time we had an inverter with an internal fault which
> eventually"blew up" with a loud popping noise and smoke billowing out of
> it. That happened after resetting a trip breaker multiple times. This case
> seems to be unrelated to those issues. I'm perplexed.
>
> Jason Szumlanski
> Florida Solar Design Group
>
>
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