# State the purpose of a fuse in a household electrical circuit and explain what happens inside the fuse when a fault causes the current to exceed the fuse's rated value.

> Cambridge International IGCSE Physics (0625) — 4.4 Electrical safety · Explain · 4 marks

> Household appliances are connected to the mains supply using plugs that contain a fuse. The fuse is a short length of thin wire with a known melting point.

## Mark scheme (4 marks)

1. A fuse protects the appliance (and/or wiring/circuit) from damage due to excessive current / acts as a safety device to prevent overheating or fire
2. When the current exceeds the rated value, the fuse wire heats up
3. The fuse wire melts / breaks the circuit
4. Current stops flowing / the appliance is switched off / no current reaches the appliance

## Key terms

- [fuse](https://www.gradenine.co.uk/glossary/fuse)
- [current](https://www.gradenine.co.uk/glossary/current)
- [circuit](https://www.gradenine.co.uk/glossary/circuit)
- [rated value](https://www.gradenine.co.uk/glossary/rated-value)

## Related

- [Revision notes for Cambridge International IGCSE Physics (0625)](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/state-the-purpose-of-a-fuse-e9182c68) · Published by Druglandscape Ltd.