Fuse

Fuses protect circuits and appliances from damage caused by excessive current. The fuse wire melts when too much current flows, breaking the circuit.

Fuses are placed in the live wire so the appliance is disconnected from the high-voltage supply.

The fuse rating should be slightly above the normal operating current. For a 1 kW, 230 V appliance: $I = P/V = 1000/230 = 4.3$ A, so a 5 A fuse is appropriate.