Parallel Generators: Use of GFI

Avoid the Use of a Ground Fault Interrupter as a Service Entrance Disconnect

It is not recommended to route the generator (paired or single) into a service entrance through a ground fault interrupter. Ground fault interrupters are fine for either 120 V side of service or for dedicated 240 V service to a balanced 240 V load such as a hot tub. However, it is impossible to evenly balance the loading of the two sides of a residential service entrance. Current will flow in the neutral and this will trip a ground fault interrupter that is being used in 240 V service. This is not to be understood as a limitation of emergency power, but rather, it should be understood as an integral part of 120 V residential service obtained from two phases of 120 V at 180o phase difference.