GFCI Breaker Tripped..

[SunEagle]

No. I already explained what was going on. See post 6.

I have to agree with you. The external GFI is probably being tripped by the inverter start up procedure to test the circuit for ground faults.

Although even a little moisture can cause a path between ground and a hot lead which will also trigger the CB to open.

[ButchDeal]

Whenever I get around to inverters, I am going to have to unlearn a lot. I thought inverters only went to 'sleep' when the load was zero, I didn't know that they knew when sunrise was or when the DC input was being supplied by the panels.

Battery inverters sleep (search mode) when the load is zero.
Grid tie inverters sleep when the DC input is out of range

[max2k]

Whenever I get around to inverters, I am going to have to unlearn a lot. I thought inverters only went to 'sleep' when the load was zero, I didn't know that they knew when sunrise was or when the DC input was being supplied by the panels.

they wouldn't sleep if the load is 0 or DC input is 0 for short time but they can 'memorize' time when DC was off for the night and make sure they do housekeeping inside that window.

[Murby]

I can talk about SolarEdge specifically, but I think most inverters are the same. They go into a low power "night time mode" overnight, reducing their idle draw to just a couple watts. When power is detected on the DC input in the morning (or perhaps triggered by some sort of date/time/sunrise algorithm), even before that power is enough to push out any output, it wakes the inverter up so it can begin its daily self-tests and get ready to begin producing.

With my power meter, I can clearly see a several minutes of reverse current (consuming from the grid) from the inverter in the morning when it wakes up, and at night, when it goes through its shutdown routine. The current draw in nighttime mode is too low to be measured directly by my meter, although I can detect the few Wh that get consumed.

Thank you.. That explains a lot...

It is my opinion that the technical docs don't adequately explain a lot of the details of these devices.

[AzRoute66]

sensij, By the time I get around to inverters, I will have probably aged to the point where I can't remember my preconceived notions of what they do. Thanks.

[Murby]

Whenever I get around to inverters, I am going to have to unlearn a lot. I thought inverters only went to 'sleep' when the load was zero, I didn't know that they knew when sunrise was or when the DC input was being supplied by the panels.

In a few more years, they'll know what beer you drink too....

[sensij]

Whenever I get around to inverters, I am going to have to unlearn a lot. I thought inverters only went to 'sleep' when the load was zero, I didn't know that they knew when sunrise was or when the DC input was being supplied by the panels.

I'm talking UL 1741 transformerless grid-tie inverters. Not applicable comments to most off-grid stuff.

[AzRoute66]

Whenever I get around to inverters, I am going to have to unlearn a lot. I thought inverters only went to 'sleep' when the load was zero, I didn't know that they knew when sunrise was or when the DC input was being supplied by the panels.

[sensij]

Judging by the pattern of breaker trips, I think you're spot on.. but I'd like some clarification...

You say "when the inverter starts up"... What does that mean exactly? Are you saying when its first powered on? Or are you saying when the panels start making light in the morning and the inverter senses that power it goes through a test cycle on its own?

I'm confused because it seems to me that as long as the inverter is connected to the grid, the power to it never turns off for it to turn back on "start up"...

I can talk about SolarEdge specifically, but I think most inverters are the same. They go into a low power "night time mode" overnight, reducing their idle draw to just a couple watts. When power is detected on the DC input in the morning (or perhaps triggered by some sort of date/time/sunrise algorithm), even before that power is enough to push out any output, it wakes the inverter up so it can begin its daily self-tests and get ready to begin producing.

With my power meter, I can clearly see a several minutes of reverse current (consuming from the grid) from the inverter in the morning when it wakes up, and at night, when it goes through its shutdown routine. The current draw in nighttime mode is too low to be measured directly by my meter, although I can detect the few Wh that get consumed.

[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.

Judging by the pattern of breaker trips, I think you're spot on.. but I'd like some clarification...

You say "when the inverter starts up"... What does that mean exactly? Are you saying when its first powered on? Or are you saying when the panels start making light in the morning and the inverter senses that power it goes through a test cycle on its own?

I'm confused because it seems to me that as long as the inverter is connected to the grid, the power to it never turns off for it to turn back on "start up"...

[sensij]

Moisture failure. you have moisture somewhere bleeding current.

No. I already explained what was going on. See post 6.

[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.

[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.

[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.

[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).