GFI issues

Thread Starter


Joined Feb 26, 2009
Hello all, I have a bit of an issue with a GFI that is sourced by a 60Hz. 110VAC true sine wave inverter and I was hoping to get some troubleshooting tips if anyone would be willing to give some. This is work related, so please excuse me, but I need to be as vague as possible

The situation is this:

The GFI, (not sure what kind of power dissipation it is rated for), has two loads connected to it. Upon start-up of the system the loads draw a max of 5 A of current, shortly thereafter the GFI trips. I reset the GFI, the system draws power again and no issues after that, the GFI remains set. Again, it is only after the system has been shut down for prolonged periods of time that the GFI trips on start-up.

These are things that I have done to isolate the fault, to no avail:

1.) Test for shorts to ground in line; no shorts
2.) Swap GFI with known good one; still trips
3.) Power on only one load at a time; opens only when both loads are connected, not one or the other.

Any thoughts?
Thank you.


Joined Jan 28, 2005
Most likely your load has an AC input conditioner/filter through which the input AC voltage is being filtered. Often these AC filters contain capacitors between Line and Safety ground and Neutral and Safety ground. These caps route small amounts of current to the safety ground and this unbalances the detector circuit in the GFI and that trips the protection breaker.