Abstract: A polyphase power system with a system safety ground supplies a plurality of power phases over a respective plurality of power lines to power a load. A plurality of phase fault detectors of a fault detection component monitor the plurality of power lines, respectively. A phase fault detector, of the plurality of phase fault detectors, monitors a power line of the plurality of power lines. The phase fault detector outputs a threshold voltage with a voltage divider coupled with the power line. The threshold voltage is a line-to-ground voltage relative to a localized ground. A capacitor coupled between the localized ground and the system safety ground provides a direct current offset to the localized ground upon a ground fault condition. The phase fault detector compares the threshold voltage with a reference voltage to make a determination of an existence of the ground fault condition in the power line.