Apologies in advance for the long post, but this one has me stumped. I’m a master electrician, I’ve been an electrician for 10+ years and I have dealt with my fair share of nuisance trips, but this one takes the cake. I’m hoping some other electrical nerds might be able to help.
I have a customer that has an outbuilding on her property that she says has several GFCI breakers that are tripping at random times during the day and night. When I say several, I mean like 12-18 different circuits nuisance trip every single day. They aren’t the same circuits tripping every day. It’s a different collection of circuits every day (although some circuits seem to be tripping more often than others, sometimes twice a day). The circuits often trip with no load and it seems like they trip more often at night when no one is working. She says they trip more often when there has been some moisture and when it’s colder. I have also verified much of this myself, I’ve been stopping in here and there for about a week and I’ve noticed the same things.
Now let me give you some background: The panels are located in a horse stable (a very fancy horse stable) that has three separate services feeding it: a 100A genset panel and 2 200A (LS-1 and LS-2) panels. The nuisance tripping for the GFCI breakers is exclusive to the two 200A panels and the place was completed in 2022 - so it’s a virtually brand new building. It’s an Eaton panel with BR series plug on neutral GFCI breakers. The services originate at one pedestal, go underground to vault with AL 350’s in 2 1/2” PVC. Inside the vault, the wires are spliced and then turn into two parallel runs each of 350 aluminum in 2 1/2” HDPE (so no joints) and run 300’ to another vault, are spliced again and converted to 250 copper, and go underground to the stables. There is also a hay barn fed from LS-2 that has 4 GFCI breakers on the sub panel there - these breakers also nuisance trip at the same alarmingly high rate. There is water in the conduits at the lower vault, but I’m not necessarily surprised by that since condensation would have accumulated there. It does also seem that condensation is accumulating in that vault as well.
What I’ve done so far:
- removed the GFCI breaker on two circuits and installed standard breakers with GFCI devices. No nuisance trips on those circuits after.
- replaced the previous breakers with brand new eaton GFCI breakers. These circuits still nuisance trip at the same rate.
- installed two square d breakers in the panel just to see if there was a brand difference on the nuisance trips. These breakers still trip at the same rate.
- verified torquing on all branch circuits, mcb’s and taps
- performed an insulation test on all conductors between the vaults
Anything I’m missing as to why this might be happening and how I can fix it? less
I have a customer that has an outbuilding on her property that she says has several GFCI breakers that are tripping at random times during the day and night. When I say several, I mean like 12-18 different circuits nuisance trip every single day. They aren’t the same circuits tripping every day. It’s a different collection of circuits every day (although some circuits seem to be tripping more often than others, sometimes twice a day). The circuits often trip with no load and it seems like they trip more often at night when no one is working. She says they trip more often when there has been some moisture and when it’s colder. I have also verified much of this myself, I’ve been stopping in here and there for about a week and I’ve noticed the same things.
Now let me give you some background: The panels are located in a horse stable (a very fancy horse stable) that has three separate services feeding it: a 100A genset panel and 2 200A (LS-1 and LS-2) panels. The nuisance tripping for the GFCI breakers is exclusive to the two 200A panels and the place was completed in 2022 - so it’s a virtually brand new building. It’s an Eaton panel with BR series plug on neutral GFCI breakers. The services originate at one pedestal, go underground to vault with AL 350’s in 2 1/2” PVC. Inside the vault, the wires are spliced and then turn into two parallel runs each of 350 aluminum in 2 1/2” HDPE (so no joints) and run 300’ to another vault, are spliced again and converted to 250 copper, and go underground to the stables. There is also a hay barn fed from LS-2 that has 4 GFCI breakers on the sub panel there - these breakers also nuisance trip at the same alarmingly high rate. There is water in the conduits at the lower vault, but I’m not necessarily surprised by that since condensation would have accumulated there. It does also seem that condensation is accumulating in that vault as well.
What I’ve done so far:
- removed the GFCI breaker on two circuits and installed standard breakers with GFCI devices. No nuisance trips on those circuits after.
- replaced the previous breakers with brand new eaton GFCI breakers. These circuits still nuisance trip at the same rate.
- installed two square d breakers in the panel just to see if there was a brand difference on the nuisance trips. These breakers still trip at the same rate.
- verified torquing on all branch circuits, mcb’s and taps
- performed an insulation test on all conductors between the vaults
Anything I’m missing as to why this might be happening and how I can fix it? less
