Will and ground fault current interrupter socket trip if an AC to DC converter has a ground fault on the DC side? If not can someone recommend a way to sense a difference between DC supply current and the return current, so as to detect a ground fault?

 

If the AC to DC converter does not have a transformer to isolate the AC side from the DC side, the GFCI will not trip when the DC side is grounded.

If the AC to DC converter does have a transformer to isolate the AC side from the DC side, the GFCI probably will not trip when the DC side is grounded. And whether it tripped under that condition is dependent on how much AC leakage there is between the AC side of the circuit and the DC side of the circuit.