One more question, do you have pvc or rigid conduit run from panel 2 to panel 3? If metal, then you may very well have a slightly damaged wire. It may be picking up moisture in the pipe and losing some potential to ground, enough to trip.


-Chris
1 acre pond
Currently managing:
FHM, GSH, GSF, BG, PS, RES, LES, YP, SMB, LMB, HSB, RBT, WE, CC, FHC, and Grass Shrimp