A safety device that breaks the flow of electricity whenever a circuit is overloaded. Modern installations do not use fuses as safety devices. Older homes and buildings may still use fuses. Each circuit will have a current rating. Should that current rating be exceeded, it may become dangerous and may cause a fire, injury or even death. To prevent this, a fuse is placed in line with this circuit, always on the source side, and breaks the flow of electricity by overheating and melting. A fuse is chosen with a rating always slightly less than the maximum current rating of a circuit. Fuse wire is still readily available and is rated in amps. More commonly, fuses will be found in some electrical and many electronic appliances to protect them from possible internal faults that may occur and cause large current flows that result in serious damage.