petersonra
Senior Member
- Location
- Northern illinois
- Occupation
- Semi-retired engineer
I have seen 120 volt GFCIs fail due to over voltage. They don't seem to be especially robust.Is the GFCI fed by a multiwire branch circuit? If so, maybe the neutral has a poor or intermittent connection and it's causing an overvoltage to occur sometimes on the GFCI, and thereby causing it to fail. Perhaps @don_resqcapt19 was thinking along these lines when he asked whether the garage has a 120/240V feeder.

