# Electric Fuse: Working Principle and Functions and Uses

An electric fuse is a kind of safety device used to limit the flow of current in a functional electric circuit. Whenever there is an excess flow of current or electric current overload through the circuit, the fuse melts down thus breaking the electric circuit and avoid a short circuit.

Wires made from some special materials melt quickly and break when large electric currents are passed through them. These wires are used for making electric fuses. In all buildings, fuses are inserted into all electrical circuits. There is a maximum limit on the current that can safely flow through a circuit.

If by accident the current exceeds this safe limit, the wires may become overheated and may cause a fire. If a proper fuse is there in the circuit, it will blow off and break the circuit. A fuse is thus a safety device that prevents damages to electrical circuits and possible fires.

Fuses of different kinds are used for different purposes. Fuses are generally used the nichrome wire, tie a thin strand of in electrical appliances.

One reason for excessive currents in electrical circuits is the direct touching of wires. This may happen if the insulation on the wires has come off due to wear and tear. This may cause a short circuit.

Another reason for excessive current can be the connection of many devices to a single socket. This may cause overload in the circuit. You might have read reports in newspapers about fires caused by short circuits and overloads.

These days Miniature circuit breakers (MCBs) are increasingly being used in place of fuses. These are switches that automatically turn off when the current in a circuit exceeds the safe limit. You turn them on and the circuit is once again complete.

Working Principle of Fuse

The working of electric fuse is based on heating effect of electric current. An electric fuse is composed of thin metallic wire of non flammable material.

Whenever there is an overload of electric current, the heat generated by the circuit leads to the melting of the fuse (an electric fuse has a low melting point) and protection of the electric circuit.

Functions of Electric Fuse

Let us understand the important functions of electric fuse.

1. Prevents fire, breakdown and protects electrc wiring.
2. Restricts the flow of current.
3. Terminates the circuit when too many appliances are connected in a single circuit and overloading of electric current happens.
4. Prevents blackouts.
5. Prevents damage that can happen due to mismatched loads.
6. A fuse acts like a circuit breaker and prevents us from electrocution!