Why can't the fuse be replaced with copper wire

Release Time:

2020-07-30

Although a fuse is also a metal wire, it is different from ordinary copper and iron wires. It is soft and made of lead, antimony, or low melting point alloys such as lead and tin. Its resistivity is relatively large, the melting point is relatively low, and it is inherently afraid of heat. Due to the thermal effect of the current, as long as the current passing through the fuse exceeds the rated current of the fuse and reaches the fusing current, the fuse will quickly fuse and automatically disconnect the circuit from the power supply. In this way, the strong current can no longer enter the user's home, thereby preventing the meters, electrical appliances or wires connected to the circuit from being burned out due to excessive current. The fuse is broken and cannot be replaced with copper wire or iron wire. If copper wire or iron wire is used instead of fuse, because of their high melting point, even when a strong current passes, it will not be blown, and the purpose of automatically cutting off the current will not be achieved, and it will not play the role of insurance, which is very dangerous. In addition, when installing the fuse, you must pay attention to choosing the appropriate thickness. There are many specifications of fuses, usually expressed by its rated current. For fuses of the same material, the larger the cross-sectional diameter, the larger the rated current allowed to pass. Therefore, when choosing, you must first calculate the maximum working current through the circuit according to the total wattage of the electrical appliance, so that the rated current of the fuse is equal to or slightly greater than the maximum working current of the circuit. In this way, it is not only ensured that the fuse can work normally, but also that the fuse can be quickly blown to cut off the circuit when it encounters an excessive current. If the rated current of the fuse is too large, when there is an excessive current in the circuit, it will not be blown, and it will not play the role of insurance, which is no different from connecting steel wires and iron wires; In the case of electricity, the fuse will also blow, causing a power outage.