What is an electrical fuse? Why is it important?

An electrical fuse is an electrical safety device whose main purpose is to protect electrical equipment from excessive currents as well as from short circuits or mismatched loads. An electrical fuse is placed at the weak point of an electrical circuit. When the circuit current is too high, the wire inside the fuse will melt and stop the current from flowing through, this is because the fuse has a low melting point and acts as a miniature circuit breaker.

The wires inside the electric fuse are carefully selected so that when the normal specified current flows through the circuit, the wires inside the fuse will not be damaged in any way, which is equivalent to the fact that the fuse is a part of the circuit and is able to form a complete circuit so that the current can flow through.

Types of electric fuses: According to the input voltage, there are mainly DC fuses and AC fuses.

1. DC Fuses

DC fuses will cut off the circuit when the current is too high, so the arc extinguishing in DC circuits is not as simple as in AC circuits. Note: Arc is a gas discharge phenomenon, a momentary spark produced by the passage of electric current through some insulating material (e.g. air).

1.1 Tubular Fuses

This type of fuse is a fuse wire encapsulated in a glass casing with metal caps at both ends, and can be used for electric motors, air conditioners, refrigerators, and other electrical appliances.

1.2 Automotive Fuses

Automotive fuses protect the vehicle’s internal wiring harness and various modules.

1.3 Self-recovering Fuses

This kind of fuse is self-recovery, when there is a large current flow to generate heat, the organic polymer will expand, and it will recover by itself after the heat drops, mainly used in computer power supply, cell phone charger, aviation equipment and so on.

2.AC Fuses

2.1 Low Voltage Fuses

These fuses are very common and have a small voltage rating.

2.1.1 Reconnectable Fuses

Reconnectable fuses are mainly used for small current circuits, the fuse holder can be easily inserted and removed from the base without opening the main switch, and can be used for industrial and household wiring, totaling small current use in low voltage systems.

2.1.2 Enclosed Fuses

Enclosed fuses are used in small industries to protect machines.

2.1.3 Drop Fuses

A fuse that blows and causes the fuse element to fall out under the force of gravity, this type of fuse protects outdoor transformers.

2.1.4 Pin Fuses

Knockout fuses are used to close tripped or indicated circuits, they have sufficient force and displacement.

2.1.5 Switching fuses

Switching fuses are used in low-voltage and medium-voltage circuits, which can be safely disconnected on the basis of a current rating of approximately three times the load current.

2.2 High Voltage Fuses

High voltage fuses are mainly used for motor protection, protection of small transformers (control of power transformers), and protection of general-purpose equipment requiring rapid overload protection.

2.2.1 HRC Fuses

A high breaking capacity fuse is a fuse that can carry a short-circuit current for a certain period of time, and will blow when the circuit fails.

2.2.2 Jet Fuses

An injection fuse is a type of fuse used in electronic throttles to protect the normal operation of electronically controlled injection systems.

Why are fuses so important

1. To protect electrical equipment

Fuses protect electrical equipment from damage, which can occur when high currents are passed or when there is too much heat, which can damage electrical equipment in a home or business, and in severe cases, can lead to fires. Repairing or replacing electrical equipment costs a lot of money, and having a fuse in the circuit avoids these problems and protects the electrical equipment from damage and fires.

2. Prevent short circuit

A short circuit in the circuit will appear a lot of current, the fuse can safely cut off the circuit, to avoid damage caused by the current is too large.

3. Acting as a barrier between the circuit and the human body

When a circuit malfunction occurs, a fuse can disconnect the circuit and prevent the human body from coming into contact with the energized equipment and causing harm. If there is no fuse, it will cause damage to the equipment, and we may touch the energized equipment because we are not sure what causes the malfunction, resulting in electrocution accidents.

4. Prevent load mismatch

When there are too many devices in the same circuit, the current overload will occur, this time there will be a short circuit and the fuse will blow. If there is no fuse, it will cause damage to the equipment, and in serious cases, fire or electric shock will occur.

5. Preventing ground faults

If the fire wire comes into contact with anything that is grounded, such as metal pipes, human body, distribution box, etc., when electricity is energized, it will cause a ground fault, which will result in a blown fuse.

Conclusion

Fuses are equivalent to an electrical circuit protection that protects electrical appliances and individuals to the maximum extent possible. Whether in a home or in a business, whenever we need to use electricity, we need to use fuses, just some categories are different.