# How does a Fuse work in Circuits?

Updated on June 1, 2013

Electricity has become one of the most essential sources of power for our daily life. But it is also very dangerous. This is where fuses come into play and protect us from the dangers of electricity. It has occupied such a prominent and basic place in our lives that we face a lot of problems even to complete our daily routines when we do not have electric power. But electricity is potentially dangerous to our lives and properties if it is not used in a systematic and safe way. The electricity we receive from the Electricity Company reaches our house through a pair of wires or a set of 4 wires depending on the type of supply we get for our house or factory.

## Single Phase Power Supply

In case of a single phase power supply one of the two wires carries the power from the power generating system while the other one is connected to the earth or a neutral so that a potential difference can be created between the two wires. This drives the current to flow through the wire. In our home we have different circuits that take the electric power to all the places and each of these circuits are provided with a fuse arrangement as a protection device.

The electric power that is supplied to your home will be at 240 Volts or 120 volts and this is the pressure at which the electric charge is forced to flow through the wire. The amount of current that flows through the wire is specified in Amperes; that gives the quantity of electric charge that flows through the circuit. The electric power is connected to a load that resists the flow of the current and this makes them work by taking the power from electricity. The wires that carry the current and the one that is connected to the earth are placed in such a way that they do not connect with each other directly but only through a load or an appliance.

## How a Short Circuit Occurs?

The amount of current that flows through an electric circuit depends on the resistance offered by it as per the appliance connected to it. So, this limits the amount of electric power flowing through the circuit and this enables the circuit and the appliance connected to the power to function properly. But if something goes wrong and the hot wire carrying the current and the one connected to the earth get connected the entire amount of electric power flows through the wire and gets neutralized. This called as a short circuit and the circuit gets broken. Due to the excessively high amount of electricity flowing through the wire it gets overheated and may lead to fires and other hazards, besides damaging the appliance connected to the damaged circuit.

How can a short circuit be prevented?

This is prevented by using fuses in every circuit. This is a very simple safety device that guards against short circuits. A fuse is nothing but a piece of thin wire made of some special alloy that is sensitive to heat. The fuse is placed in the circuit in such a way that the current has to flow through it. The fuse wires come in different specifications depending on how much current the circuit is designed to carry. When there is a short circuit, the fuse wire gets heated due to the excess flow of electric power and it melts and breaks the circuit stopping the flow of electric power.

Thus, the fuse arrangement is able to protect the appliances and also prevents the overheating of the wires leading to electric fires. In the modern days we use more advanced circuit breakers instead of old type fuse wires and get more protection from them.

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