What is the purpose of an equipment grounding conductor (EGC) in a circuit?

• A. It carries normal circuit current during operation.
• B. It provides a low-impedance path to earth for fault currents, reducing shock risk and enabling protective devices to trip.
• C. It replaces the neutral conductor.
• D. It is used for shielding only.

Answer: (B)

The purpose is to provide a low-impedance path to earth for fault currents so that any fault causing metal parts to become energized will quickly cause a protective device to trip, reducing shock risk.

In normal operation, current flows from the hot through the load and returns on neutral; the equipment grounding conductor carries little to no current. If a fault brings a live conductor into contact with a metal enclosure, the fault current returns to earth through the grounding conductor. That substantial fault current makes the overcurrent protective device (breaker or fuse) operate quickly to clear the fault. At the same time, grounding keeps exposed surfaces near earth potential, limiting the shock hazard. Some protection systems (like GFCIs) also rely on this path to detect imbalances and trip when leakage to ground occurs.