There are always ground faults according to our LIM's (Line Isolation Monitors)We use them instead of GFCI in operating rooms.Basically they will read from .2 to .8 ma with special silicon gel low leakage appliance cords etc in perfict condition.The LIM will go into warning at 1.5ma and full alarm at 2ma.Dust between the receptacle screws or even wiping down the OR table with a damp cloth will set it off.
I would say partial ground faults are everywhere its just where and what point it becomes a problem.
