I've got a Cutler Hammer C-series breaker that trips for no apparent reason. It's a RDC frame, 1600A, with 310 Digitrip, and GFEP.
6 months ago it tripped 2 or 3 times over a few days. We thought it might have something to do with when different equipment came on-line but couldn't find a problem. The problem went away on its own.
About 2 weeks ago, it tripped again. and has done so 3 more times, including today. Can happen at any time during the day but we don't think it's happened over night. Monitoring equipment on the switch gear shows that we've never had a current draw of more than 700A so it seems like it must be tripping due to a ground fault and not over current. Ground fault interrupt rating is 200A.
I would think we'd notice a 200A ground fault somewhere but nothing stands out. We reset the breaker and it's fine for a few days.
We've checked for current on the ground path and we have seen a fraction of an amp that comes and goes but we're chalking that up to coupling and haven't seen anything near 200A.
I've got the manual for this breaker and I'm going to read through it tonight but I'm hoping somebody has seen this before and can point me in the right direction. If it is a ground fault. I don't know how we're going to find a ground fault that shows up for a few seconds every few days.
Any insight is appreciated.
Thanks
