Copper 3-prong roof clip (25 pack) (ET-CL-CU-P25)

A 2 pole single-phase 240V circuit works by continuously monitoring the current flowing through both hot wires of the circuit. If it detects even a slight imbalance between the current on each hot wire (indicating a ground fault), it will quickly trip, cutting off power to the circuit. Essentially, it compares each leg of the 240V circuit and trips if they are not precisely equal.