Final answer:
A properly wired GFCI receptacle works by comparing the currents in the live/hot and neutral wires and trips if there is an imbalance, indicating a leakage current over a threshold of 5 mA, to prevent hazardous conditions.
Step-by-step explanation:
When a Ground Fault Circuit Interrupter (GFCI) receptacle is properly wired, it functions to prevent electric shock by detecting differences in electrical current between the live/hot and neutral wires. If the currents are equal, they will induce equal and opposite electromotive forces (emfs) in the induction coil within the GFCI. However, if an imbalance is detected, indicating leakage current which could be returning to the voltage source via an unintended path, the GFCI will trip the circuit breaker to prevent potential hazards. GFCIs are designed to trip if the leakage current exceeds 5 milliamps (mA), which is considered the maximum harmless threshold for electric shock. Even when the leakage current is safely grounded, the tripping forces repair of the issue.