1. Fuses

2. How does a fuse work?
A fuse is connected directly into an electrical circuit. If the electric current surges to a dangerous level, the metal in the fuse melts and the circuit is broken, preventing overheated wires in the walls of the house from starting a fire.
Never substitute a fuse of greater capacity than that specified for a particular circuit. If the fuse has the ability to carry more current than originally designed, the wires will heat up before the fuse melts, and this could start a fire.

3. Boardworks GCSE Additional Science: Physics Electrical Safety
What is a fuse?
fuse
A fuse is a safety device, which breaks the circuit, if the current is too high.
This protects the cable from overheating and catching fire.
Sockets and extensions that are overloaded with appliances are especially at risk of catching fire.
All UK plugs are fitted with fuses. Fuses are available in a range of amperes to suit different current values.
Teacher notes
See the Boardworks GCSE Science (Physics) ‘Mains Electricity’ presentation for more information about fuses and circuit breakers.

4. Boardworks GCSE Additional Science: Physics Electrical Safety
How do fuses work?
A fuse contains a thin wire, which melts if the current is too high.
This breaks the circuit and so electricity is unable to flow through the appliance.
The appliance stops working and any danger has been averted.
thin wire
Fuses act as an early warning system, preventing appliances from being damaged by surges in electricity and warning owners of faults.
Symbol for a fuse