Abstract: A current sensing, self-heating device for protecting equipment against abnormal current levels which is automatically resettable under mild overcurrent conditions and nonresettable under severe overcurrent conditions. The device comprises a thermostat metal assembly with a temperature compensating portion and an actuating portion which is placed adjacent a nonresettable two-position snap-acting blade electrically connected to ground. During normal operation current flows from the line source through the actuating portion of the thermostat metal assembly to the equipment. However, if an overcurrent condition occurs the heat generated in the actuating portion of the assembly will bend the assembly and cause it to make contact with the blade shorting the current from the line source to ground.