We've got a 2500A GFI breaker that has tripped several times on a ground fault that we can't find. It happens days apart.
This is one of two main breakers that feeds a 260K sq ft building at 480V. There are several small and large transformers all over the building to provide other voltages.
I called in our electrical contractor since we were stumped and he told us that a GFI can "see" a ground fault even if it's on the secondary side of our transformers.
I'm not sure I believe this and wanted more opinions.
It seems to me that the GFI breaker feeding the transformer can't possible know if there's an imbalance on the secondary side.
