Mains electricity (6.2.3.2) | AQA GCSE Combined Science: Trilogy (8464) — Physics — Higher

Content	Key opportunities for skills development
$Most electrical appliances are connected to the mains using three- core cable. The insulation covering each wire is colour coded for easy identification: live wire - brown neutral wire - blue earth wire - green and yellow stripes. The live wire carries the alternating potential difference from the supply. The neutral wire completes the circuit. The earth wire is a safety wire to stop the appliance becoming live. The potential difference between the live wire and earth (0 V) is about 230 V. The neutral wire is at, or close to, earth potential (0 V). The earth wire is at 0 V, it only carries a current if there is a fault. Students should be able to explain: that a live wire may be dangerous even when a switch in the mains circuit is open the dangers of providing any connection between the live wire and earth.$	$WS 1.5$

Most electrical appliances are connected to the mains using three- core cable.

The insulation covering each wire is colour coded for easy identification:

live wire – brown

neutral wire – blue

earth wire – green and yellow stripes.

The live wire carries the alternating potential difference from the supply. The neutral wire completes the circuit. The earth wire is a safety wire to stop the appliance becoming live.

The potential difference between the live wire and earth (0 V) is about 230 V. The neutral wire is at, or close to, earth potential (0 V). The earth wire is at 0 V, it only carries a current if there is a fault.

Students should be able to explain:

that a live wire may be dangerous even when a switch in the mains circuit is open
the dangers of providing any connection between the live wire and earth.

Mains electricity

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Learning Objectives