A Fuse Vs. a Circuit Breaker in a Car

Automotive fuses and circuit breakers perform similar functions.

Automotive fuses and circuit breakers are both designed to protect an electrical device or wiring from damage. However, these devices provide protection in different ways that are important for car owners to understand when maintaining their cars.

Fuse Operation

A fuse works by using a thin metal strip that can only handle a specific amount of amperage. The amount of amperage that a fuse is designed to handle is stamped into the fuse body. When this amount is exceeded, the metal strip is overheating causing it to break. The fuse must then be replaced to restore electrical power to the circuit.

Circuit Breaker Operation

When a circuit breaker experiences an overload, a moveable arm within the breaker is heated causing it to move out of place and break the circuit. When the arm cools, it moves back into place and closes the circuit. Manual reset circuit breakers have a reset button that must be pushed to make the breaker operate.

Causes of Failure

Fuses and circuit breakers are designed to provide enough amperage to supply the components they protect. When either fails it is a sign of a problem. If you experience repeated failure of a fuse or circuit breaker, inspect the wiring and device for problems.

References

• AA1Car: Library, Automotive Power Centers, Fuses & Relays
• 2CARPROS: How Car Fuse Works