Explain how the fuse, the MCB and earthing protect a household circuit and the people using it.

1. 1 · Say why protection is needed. Leakage of current, short circuits and overloading can cause shocks and fires.
2. 2 · Fuse. A low melting point alloy wire in series in the live wire. Too much current makes it melt and break the circuit.
3. 3 · MCB. A switch that turns off by itself on overload or short circuit, and can be switched on again after the fault is fixed.
4. 4 · Earthing. The green earth wire joins the metal body to a copper plate deep in the ground. Leaking current goes to earth, not through a person.
5. 5 · Draw the earthing. [Sketch: appliance body joined by the earth wire to a copper plate buried in the ground]
6. 6 · Link to daily life. This is why an iron or fridge has a three-pin plug, with the longest pin for earth.

Scoring tip: Give each device its own line: what it is, where it is joined, and how it acts. That earns one mark per device.