FDD50P-364 is a 50-amp, 3-pole, 4-wire, self-test, ground fault circuit interrupter (GFCI) manufactured by Sunbank. It is used to protect against electrocution due to ground faults and overloads. The GFCI monitor the current in the circuit and if a difference between the hot and neutral side is detected, the GFCI trips and disconnects the power to the circuit. The FDD50P-364 is cULus listed, and is suitable for use on 120/240V, single-phase AC circuits. It is also available in a dual-voltage version with separate 120V and 277V connections.