Electrical Safety

Live wire

Carries alternating potential difference from mains (dangerous even when switch is off)

Neutral wire

Completes the circuit; close to 0 V

Earth wire

Safety wire that carries current to ground if casing becomes live

Earth wire colour

Green and yellow

Live wire colour

Brown

Neutral wire colour

Blue

Why appliances are earthed

Prevents electric shock if live wire touches metal casing

Double insulation

Plastic casing + no exposed metal → no need for earth wire

Fuse purpose

Melts and breaks circuit if current is too high

Circuit breaker

Switches off circuit automatically if current is too high

Fuse vs circuit breaker

Breakers reset; fuses must be replaced

Why fuses are in live wire

To cut off supply immediately if fault occurs

Danger of live wire

Can cause fatal electric shock even if appliance is off

Cable insulation

Prevents wires touching and causing short circuits

Short circuit

Live wire touches neutral → very high current → fuse blows

Overheating risk

Too much current causes wires to heat up → fire hazard

Safety in wet conditions

Water conducts electricity → increases shock risk

Plug feature

Cable grip holds cable securely to prevent strain on wires

Key idea

Electrical safety devices protect users by preventing shocks and overheating