Self-calibrating circuit interrupter

A circuit interrupter includes phase and neutral conductive paths between a line side and a load side of the circuit interrupter. Differential and ground/neutral transformers are coupled to the phase and neutral paths. A circuit interrupter chip is coupled to the phase and neutral conductive paths, and to respective fault inputs from the transformers. A calibration circuit including a calibration resistor is coupled to a circuit interrupter controller. An interrupter circuit is configured to open the phase and neutral paths when a predetermined ground fault current condition is sensed. The circuit interrupter controller is configured to perform a self-calibration function to adjust a ground fault current trip-time response to maintain the ground fault current trip-time response within a predetermined range. Methods for using the self-calibrating circuit interrupter are also disclosed.