Why does a fuse blow or circuit breaker trips?

Answer 1

Both devices are safety measures for the electrical circuit. The home fuse is a glass affair with a burnable core. If the core melts, the circuit opens. The circuit breaker does the same thing, but is a "reset" device, meaning that it can be used over and over again. The fuse is replaceable, but not "reset-able." Both systems are used in modern homes, but the fuse system is being replaced by the circuit breaker system.

Answer 2

when a circuit draws more current than the fuse is rated for the element (a piece of metal) in the fuse overheats and melts, therefore breaking the path of the current and no more current flows to the circuit. The fuse element is made to melt at a certain amount of current flowing through it and acts as a safety switch.

A circuit breaker acts the same way, it uses the heat generated by the current flowing though it to trip (open) the circuit when a certain current flow occurs. This is done through a thermo-magnetic mechanism.

Answer 3

Circuit breakers and fuses are designed to protect the wiring in the circuit from overheating and possibly melting or causing a fire. Each gauge (size) of wire will carry only so much electrical current before it overheats. The circuit breaker/fuse is designed to blow/trip at a safe limit before the wiring is overloaded. Larger circuit breakers and fuses protect larger wiring.

The cause of the overload is often a faulty electrical appliances that has shorted out and is allowing electrical current to flow unrestricted. The cause could also be too many appliances connected to the same circuit and, therefore, drawing too much current between them.

In any case, the circuit breaker or fuse is designed to blow or trip long before the wiring can become overheated. This is also why you should never replace a smaller amperage fuse with a larger one.

Answer 4

The current through the device exceeds the rated value. In a fuse the wire in the fuse just melts. In the breaker a switch opens up which is usually caused by heat that trips the breaker. The heat is caused by the excessive current inside the breaker.

Answer 5

Its because of the heavey load that your are pluging