I strongly suspect the CH240 combined breaker was compromised (we will see). Since it happened that two different strings tripped, I doubt I have two microinverters with internal faults. It has to be the combined breaker. I was just surprised that branch circuit breakers were tripping simultaneously with the combined output breaker.
Of all the supply side connected systems I have installed, I have never seen a combined output fusible disconnect fuse blow, but I have seen many combined output breakers tripped. I was worried early on that I would be replacing fuses constantly, but that has not been an issue whatsoever. On Thu, May 21, 2020 at 11:15 AM <scot.a...@solarcentex.com> wrote: > Actually, we had a IQ7 string loaded up to its max panel size and max > string length and in the spring on cool, clear day, it tripped the string’s > associated breaker in the Enphase combiner. > > > > We reset but of course that breaker was impaired and it tripped again. We > replaced and never had an issue going forward. We suspect the breaker was > less than perfect from the start as we’ve add equally nice days since. > > > > This almost reminds me of loading up Outback FM80. It says 4,000 watts but > in reality, 3,600 is the max when amps spike. I will be extra careful going > forward on IQ7 string length when going to the max published… > > > > My story. > > > > Scot > > > > *From:* RE-wrenches <re-wrenches-boun...@lists.re-wrenches.org> *On > Behalf Of *Jason Szumlanski > *Sent:* Thursday, May 21, 2020 8:57 AM > *To:* RE-wrenches <re-wrenches@lists.re-wrenches.org> > *Subject:* [RE-wrenches] Enphase intermittent breaker trippjng > > > > 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 > > > > > _______________________________________________ > List sponsored by Redwood Alliance > > List Address: RE-wrenches@lists.re-wrenches.org > > Change listserver email address & settings: > http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org > <https://mailtrack.io/trace/link/796b1796eb4c075a74298513a530f62e4a496cb2?url=http%3A%2F%2Flists.re-wrenches.org%2Foptions.cgi%2Fre-wrenches-re-wrenches.org&userId=1613865&signature=c7dea131fd9cb45a> > > List-Archive: > http://www.mail-archive.com/re-wrenches@lists.re-wrenches.org/maillist.html > <https://mailtrack.io/trace/link/c06e48af2da3d129a58c08ef2043bd2d8fcbef6f?url=http%3A%2F%2Fwww.mail-archive.com%2Fre-wrenches%40lists.re-wrenches.org%2Fmaillist.html&userId=1613865&signature=06899a19621f54d8> > > List rules & etiquette: > www.re-wrenches.org/etiquette.htm > <https://mailtrack.io/trace/link/215cb4d0fcfb04e4124aae9b2616249f1eef5542?url=http%3A%2F%2Fwww.re-wrenches.org%2Fetiquette.htm&userId=1613865&signature=8bc84049c81c183c> > > Check out or update participant bios: > www.members.re-wrenches.org > <https://mailtrack.io/trace/link/27c3e706e7f2b4836b1669b31c9454db7fee1b52?url=http%3A%2F%2Fwww.members.re-wrenches.org&userId=1613865&signature=4a75a2d55681f39a> > >
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