We just had a new ground fault alarm and monitor system installed in my plant (Bender COM465IP) and right off the get go it picked up a ground fault that the previous system was not alarming too. It's saying I have a 25mA insulation fault on this circuit. With the Bender system I can tone the line to trace the circuit. However, I cannot locate the signal anywhere on this circuit and neither could the Bender representative that did the start up on the system. The circuit goes from the switchgear to a 480/120V transformer and then out to two smaller 120V panels. I cannot get the fault to clear, cannot locate the fault, and all circuits off this input is functioning 100% with no issues.
I'm stuck on where to go next with this issue. Anyone have any ideas?