Abstract: An inductance coil is clamped onto the cable which is to be monitored. For normal line currents, the coil produces a signal voltage which charges a reset capacitor which in turn periodically discharges to an indicator to show a no fault condition. When the line current goes above a predetermined fault level and remains at that level for a corresponding fault time period, the coil develops a signal voltage sufficiently high to charge a "set" capacitor that discharges to the indicator to show a fault condition. The indicator continues to show the fault condition until normal current has returned to cause the "reset" circuit to operate to indicate no fault. To insure that the set capacitor discharges in a manner to indicate reliably the fault condition, there is provided a voltage responsive variable impedence in the circuitry to charge the set capacitor. This variable impedence matches the fuse characteristic in the main power line.