We may come across a scenario where a fuse goes out during the operation of a machine, and there is no replacement fuse of the same type around, and this is when we may think: can I use a copper wire to replace the fuse for a short period of time?

The answer is no. If you replace the fuse with a copper wire, it may cause a fire, damage to the machine, and may even lead to casualties. A blown fuse can only be replaced with a fuse of the same type and size, not with a copper wire.

First of all, let’s understand how a fuse works. When a circuit malfunction or abnormality occurs, it is accompanied by a rising current, and the rising current may damage some important devices in the circuit, and may also burn the circuit or even cause a fire. If the circuit is correctly placed in the fuse, then the fuse will be in the current abnormally high to a certain height and heat, their own melting cut off the current, so as to play a role in protecting the safe operation of the circuit.

Fuses are made of lead-antimony alloy with high resistivity and low melting point. In the case of the same external conditions, the resistance of the copper wire is smaller and produces less heat. At the same time, because of the higher melting point of copper, it is not easy for the copper wire to fuse when there is a fault in the circuit with excessive current, thus failing to protect the circuit. When the machine keeps running with a high current, it may cause internal damage and malfunction, and may also cause injury or death if someone is next to the machine. That is why fuses cannot be replaced by iron or copper wires.

When a fuse is blown, the cause of the malfunction should be identified and eliminated before resuming power supply and replacing it with a suitable fuse. You cannot replace it with a thicker one or a copper wire, as this will not serve the purpose of insurance. If the same fuse is replaced without identifying the cause, the fuse will still blow when the switch is closed.