What is the purpose of an earth wire?

• A. To provide a low-resistance path to earth for fault current, reducing shock risk.
• B. To increase resistance in the circuit to limit current.
• C. To supply extra current to the appliance.
• D. To act as a fuse to protect wires.

Answer: (A)

The earth wire provides a low-resistance path to the ground so that any fault current has a safe route away from you and the metal parts of the appliance. If insulation fails and live touches the casing, the fault current goes through the earth wire, keeping the casing at nearly zero voltage and reducing the risk of electric shock. That large fault current also makes protective devices like fuses or circuit breakers trip quickly, cutting the supply to prevent harm. The earth wire isn’t meant to carry normal current, isn’t used to limit current, and isn’t a fuse by itself.