# Explain why the live wire in a mains plug can be dangerous even when the appliance is switched off.

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

> A student switches off a lamp at its on/off switch but leaves the plug in the socket. A friend tells her the lamp is now completely safe to carry out repairs on.

## Mark scheme (4 marks)

1. The switch breaks the circuit on the live side only (or: switching off does not disconnect the live wire from the supply)
2. The live wire carries the alternating potential difference of 230 V
3. Touching the live wire (or any part connected to it) provides a path for current to flow through the person to earth
4. This causes a serious / fatal electric shock

## Key terms

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

## Related

- [Revision notes for AQA GCSE Physics (8463)](https://www.gradenine.co.uk/learn)
- [How to answer "Explain" 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/explain-why-the-live-wire-in-43ccbf3f) · Published by Druglandscape Ltd.