What does the earth wire do?

What does the earth wire do?

• A. Connects the metal case of an appliance to earth if there is a fault
• B. Carries current away from the component
• C. Carries current to the live wire for safety
• D. Insulates the plug

Answer: (A)

The earth wire provides a safe path for fault current to flow to the ground when something in the appliance goes wrong. It’s connected to the metal casing and to the earth terminal in the plug, so if the insulation fails and a live wire touches the metal, the case can become live. The earth wire offers a low-resistance route for that fault current to go to the earth, which makes a large current flow and causes a fuse to blow or a circuit breaker to trip, cutting off the supply and protecting you from a shock. Normally it carries almost no current, which is why it isn’t part of the normal circuit. It isn’t there to carry current to the live wire, nor to insulate the plug.

The earth wire provides a safe path for fault current to flow to the ground when something in the appliance goes wrong. It’s connected to the metal casing and to the earth terminal in the plug, so if the insulation fails and a live wire touches the metal, the case can become live. The earth wire offers a low-resistance route for that fault current to go to the earth, which makes a large current flow and causes a fuse to blow or a circuit breaker to trip, cutting off the supply and protecting you from a shock. Normally it carries almost no current, which is why it isn’t part of the normal circuit. It isn’t there to carry current to the live wire, nor to insulate the plug.