# A hairdryer has a plastic casing and is sold as a double-insulated appliance. Explain why a double-insulated appliance does not need an earth wire, and state one advantage of using a circuit breaker rather than a fuse to protect the hairdryer's mains circuit.

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

> A hairdryer is connected to the mains electricity supply. It is labelled with the double-insulation symbol and its mains cable contains only a live wire and a neutral wire.

## Mark scheme (4 marks)

1. The plastic casing does not conduct electricity / electrical charge cannot flow through a plastic casing
2. There is no conducting path from the live wire to the outer casing, so the casing cannot become live / a user cannot receive an electric shock from the casing
3. A circuit breaker can be reset after it has operated / does not need to be replaced
4. A circuit breaker operates/responds faster than a fuse / breaks the circuit more quickly

## Key terms

- [earth wire](https://www.gradenine.co.uk/glossary/earth-wire)
- [circuit breaker](https://www.gradenine.co.uk/glossary/circuit-breaker)
- [fuse](https://www.gradenine.co.uk/glossary/fuse)

## 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-hairdryer-has-a-plastic-casing-4a245c41) · Published by Druglandscape Ltd.