GFCI Breaker Tripped..

[Murby]

I woke up this morning and found the GFCI breaker that feeds my solar array from the main breaker panel in the basement had tripped at some point over-night. I reset it and everything is fine (so far) but I'd like to know why it tripped.
Using a SMA Sunny Boy transformerless inverter.. Do GFCI breakers not get along with solar systems or was this just a glitch?

[max2k]

I woke up this morning and found the GFCI breaker that feeds my solar array from the main breaker panel in the basement had tripped at some point over-night. I reset it and everything is fine (so far) but I'd like to know why it tripped.
Using a SMA Sunny Boy transformerless inverter.. Do GFCI breakers not get along with solar systems or was this just a glitch?

my understanding is GFCI breaker is intended to protect load but inverter is not a load in the conventional sense. I'd replace it with normal breaker.

[Sunking]

GFCI nuisance trips are common. A CB radio passing by can trip them. GFCI does not protect against Over Current. It protects against unbalanced current. They measure the current going out on one polarity, and the current returning on the opposite polarity. If there is more than 100 ma difference, they operate. It means current is going some place it should not and bypassing the GFCI.

Assuming it worked normally, there is not a installation wiring issue. They are very sensitive and can be a number of reasons. But here is what you do:

1. Reset and see what happens. If the problem does not come back, forget it. It was a Sun Flare or kid with a walkie talkie. Who knows. GFCI are sensitive and know for false trips.
2. If issue remains, replace the GFCI. They are known to have high failure rates.
3. If replacement does not work, time to call for professional help. You have a circuit component like a Filter or Surge Protector bleeding current into ground somewhere. It could even be wet or damaged wire insulation. Whatever is above your ability to fix it yourself.

[max2k]

GFCI nuisance trips are common. A CB radio passing by can trip them. GFCI does not protect against Over Current. It protects against unbalanced current. They measure the current going out on one polarity, and the current returning on the opposite polarity. If there is more than 100 ma difference, they operate. It means current is going some place it should not and bypassing the GFCI.

Assuming it worked normally, there is not a installation wiring issue. They are very sensitive and can be a number of reasons. But here is what you do:

1. Reset and see what happens. If the problem does not come back, forget it. It was a Sun Flare or kid with a walkie talkie. Who knows. GFCI are sensitive and know for false trips.
2. If issue remains, replace the GFCI. They are known to have high failure rates.
3. If replacement does not work, time to call for professional help. You have a circuit component like a Filter or Surge Protector bleeding current into ground somewhere. It could even be wet or damaged wire insulation. Whatever is above your ability to fix it yourself.

my point was different though- I don't think GFCI provides any protection in this case- current created by inverter can leak to the ground all day long without GFCI on MSP side 'noticing' it as that current was created at the inverter. On top of that if house loads are assymetric between phases inverter output could feed one phase with higher current than another tripping GFCI inside MSP in the process. I'd just replace it with normal breaker and rely on inverter built in protection- since it is 'source' in this case it has full 'visibility' of the currents leaving and coming back.

[JSchnee21]

I agree with max2k, I don't understand the use of a GFCI breaker in this application. Is this the load side tap breaker that's tripping? OP say's its "feeding" the "array/inverter". Why would it be GFCI? Or is there an actual outdoor duplex outlet that was installed proximal to the array/inverter that's feeding something else (monitoring)?

[sensij]

Op asked the same question in another thread. The transformerless inverter has ground fault protection built in. When the inverter starts up, part of the self test routine will verify that the protection is functional, but if there is an external gfci on that circuit that doesn't know a test is happening, it will trip. OP should not have used a gfci breaker to back feed into the service panel.

[Murby]

Op asked the same question in another thread. The transformerless inverter has ground fault protection built in. When the inverter starts up, part of the self test routine will verify that the protection is functional, but if there is an external gfci on that circuit that doesn't know a test is happening, it will trip. OP should not have used a gfci breaker to back feed into the service panel.

Thank you.. I will remove it.

[tyab]

Sort of a related question - are there any GFCI breakers that are listed for backfeed (they are not labeled line and load)? I can't find any in the Square D catalog. I can find GFPE(masterpack and powerpack series) but we are talking a different level of equipment for those products.

[bcroe]

Sort of a related question - are there any GFCI breakers that are listed for backfeed (they are not labeled line and load)? I can't find any in the Square D catalog. I can find GFPE(masterpack and powerpack series) but we are talking a different level of equipment for those products.

I am pretty sure a GFI can't tell which way the power is going, but there could be other considerations.
Bruce Roe

[max2k]

Sort of a related question - are there any GFCI breakers that are listed for backfeed (they are not labeled line and load)? I can't find any in the Square D catalog. I can find GFPE(masterpack and powerpack series) but we are talking a different level of equipment for those products.

where would you need one?

[Sunking]

I am pretty sure a GFI can't tell which way the power is going, but there could be other considerations.

Not exactly directional, but they are functionally. There has to be a Line and Load side. If power is reversed, then it is possible for current to leak around the GFCI device, and the GFCI cannot detect it. That is why they are labeled Line/Load sides.

Don't get me wrong it will work, but only half arse. When power flow is in the Load direction the GFCI will operate properly. In reverse it is blind as a bat and wil not operate if there is a reverse fault.

[tyab]

Reason I brought it up is the OP stated that the GFCI breaker that the inverter ties to in the service panel tripped - and I thought there were no listed backfeed residential breakers and thus that would be an incorrect installation.

I seem to recall some discussion on MH forums about this but can't find the link.
Enphase has a white paper about Arc fault - sort of related issue - it's all related to 705.12. I have not researched it, but wonder how 2017 deals with that code section.

https://enphase.com/sites/default/fi...Compliance.pdf

I found this Square D paper - last update was 2012. Could not find anything newer from them and thus all of their residential GFCI breakers are not listed for backfeed.

http://static.schneider-electric.us/...0900DB1001.pdf

edit : I found the MH forum post. Turns out it was also talking about 705.12 - arc fault, so only indirectly related to GFCI.

http://forums.mikeholt.com/showthread.php?t=181427

Looks like the TIA completely deletes 705.12(D)(6).

[max2k]

Reason I brought it up is the OP stated that the GFCI breaker that the inverter ties to in the service panel tripped - and I thought there were no listed backfeed residential breakers and thus that would be an incorrect installation.

I seem to recall some discussion on MH forums about this but can't find the link.
Enphase has a white paper about Arc fault - sort of related issue - it's all related to 705.12. I have not researched it, but wonder how 2017 deals with that code section.

https://enphase.com/sites/default/fi...Compliance.pdf

I found this Square D paper - last update was 2012. Could not find anything newer from them.

http://static.schneider-electric.us/docs/Circuit%20Protection/0900DB1001.pdf

what is so special about backfeed breaker? It is still AC breaker and they don't get specifically listed for every possible application. Arching is a problem with DC but this is not relevant here.

[Murby]

My GFCI breaker would only trip after the sun went down and at some point before sunrise. When it trips is a mystery but since it seems to only trip between sunset and sunrise, I'm going with "its something to do with the inverter".

I have removed it and replaced with a normal breaker and no problems since.

[Sunking]

My GFCI breaker would only trip after the sun went down and at some point before sunrise. When it trips is a mystery but since it seems to only trip between sunset and sunrise, I'm going with "its something to do with the inverter".

I have removed it and replaced with a normal breaker and no problems since.

Moisture failure. you have moisture somewhere bleeding current. Bet a dollar you live where it is humid and each night dew point and temp overlap. Condensation forms on wiring and tracks to earth. If I had to guess, your GFCI breaker lost it seal allowing air and moisture inside the casing.