# A toaster has a metal casing and is connected to the mains supply using a three-core cable. Explain how the live, neutral, and earth wires each function during normal and fault conditions.

> Eduqas GCSE Physics — 7.4 Domestic uses and safety · Explain · 4 marks

> A toaster operates at 230 V from the UK mains supply. It has a metal outer casing and is plugged into a wall socket using a three-core cable containing live, neutral, and earth wires.

## Mark scheme (4 marks)

1. The live wire carries the alternating current / voltage (at 230 V) to the toaster
2. The neutral wire completes the circuit / carries current back (and is at 0 V)
3. The earth wire is connected to the metal casing so that if a fault occurs / the live wire touches the casing, a large current flows
4. The large fault current causes the fuse to melt / blow / the circuit breaker to trip, disconnecting the appliance and making it safe

## Key terms

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

## Related

- [Revision notes for Eduqas GCSE Physics](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-toaster-has-a-metal-casing-f2bb8c9f) · Published by Druglandscape Ltd.