# A washing machine has a metal casing and is connected to the mains electricity supply using a three-core cable. The three-core cable contains a live wire, a neutral wire, and an earth wire. Explain how the earth wire protects a user from electric shock if a fault develops inside the washing machine.

> Pearson Edexcel International GCSE Physics (4PH1) — 2.1 Mains electricity · Explain · 4 marks

> A washing machine has a metal casing and is connected to the mains electricity supply using a three-core cable containing a live wire, a neutral wire, and an earth wire.

## Mark scheme (4 marks)

1. If a fault occurs, the live wire may come into contact with the metal casing, making it live / causing current to flow into the casing.
2. The earth wire provides a low resistance path for the current to flow safely to earth / ground.
3. The large surge of current through the earth wire causes the fuse to melt / the circuit breaker to trip, breaking the circuit.
4. This disconnects the appliance from the mains supply, so the user cannot receive an electric shock by touching the casing.

## Key terms

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

## Related

- [Revision notes for Pearson Edexcel International GCSE Physics (4PH1)](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/a-washing-machine-has-a-metal-d84b9c1f) · Published by Druglandscape Ltd.