# Describe the role of the live wire and the neutral wire in a mains electricity supply, and explain why the live wire can be dangerous even when an appliance is switched off.

> AQA GCSE Physics (8463) — 4.2.3 Domestic uses and safety · Describe · 4 marks

## Mark scheme (4 marks)

1. The live wire carries the alternating potential difference from the supply (at 230 V).
2. The neutral wire completes the circuit (at 0 V).
3. The live wire remains at 230 V / is still connected to the supply even when the switch is open / appliance is off.
4. If a person touches the live wire, current flows through them to earth, causing an electric shock.

## Key terms

- [live wire](https://www.gradenine.co.uk/glossary/live-wire)
- [neutral wire](https://www.gradenine.co.uk/glossary/neutral-wire)
- [mains electricity](https://www.gradenine.co.uk/glossary/mains-electricity)

## Related

- [Revision notes for AQA GCSE Physics (8463)](https://www.gradenine.co.uk/learn)
- [How to answer "Describe" questions](https://www.gradenine.co.uk/tools/command-word-cheatsheet)
- [Practice this with AI marking (free)](https://www.gradenine.co.uk/start)

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Source: [GradeNine](https://www.gradenine.co.uk/q/describe-the-role-of-the-live-33770973) · Published by Druglandscape Ltd.