Ground faults and capacitance

[K2500]

I have a high resistance grounded 277/480 system. Ground fault detection shows ground fault of about .8A.

Fault level shows no change with pulser activated.
Mostly small motor loads, plus four 100HP VFD's.

Could this be a calibration issue with the detector, sensing capacitive charging current, or is there something else I should be looking for?

Equipment is Cutler Hammer, C-HRG.

 

[gar]

110501-1510 EDT

277 V at 0.8 A would be an Xc = 346 ohms. At 60 Hz this would result from a capacitance of 7.6 mfd. Quite large for leakage capacitance of wiring over a short range. Actually gigantic.

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