Why can't a fuse be replaced with copper wire?
Release time:
2020-07-30
Although a fuse is also a type of metal wire, it is different from ordinary copper or iron wire. It is soft and is made from low melting point alloys such as lead, antimony, or lead and tin. Its resistivity is relatively high, and its melting point is relatively low, making it inherently heat-sensitive. Due to the thermal effect of electric current, as long as the current passing through the fuse exceeds its rated current and reaches the melting current, the fuse will quickly melt, automatically disconnecting the circuit and power supply. This way, strong current cannot enter the user's home, thus preventing instruments, appliances, or wires connected to the circuit from being damaged due to excessive current. When a fuse blows, it cannot be casually replaced with copper or iron wire. If copper or iron wire is used to replace the fuse, due to their high melting points, they will not melt even when strong current passes through, failing to achieve the purpose of automatically cutting off the current, which is very dangerous. Additionally, when installing a fuse, it is essential to choose one of the appropriate thickness. There are many specifications for fuses, usually indicated by their rated current. For fuses made of the same material, the larger the cross-sectional diameter, the greater the rated current that can pass through. Therefore, when selecting, it is necessary to first calculate the maximum working current through the circuit based on the total wattage of the appliances, ensuring that the rated current of the fuse is equal to or slightly greater than the maximum working current of the circuit. This ensures that the fuse can operate normally and can quickly melt and cut off the circuit when encountering excessive current. If the rated current of the fuse is too high, it will not melt when there is excessive current in the circuit, failing to provide protection, which is no different from using steel or iron wire; if the rated current is too low, the fuse will also melt under normal electrical conditions, causing a power outage.
Although fuses are also a type of metal wire, they are different from ordinary copper or iron wires. They are soft and made from low melting point alloys such as lead, antimony, or lead and tin. They have a relatively high resistivity and a low melting point, making them sensitive to heat. Due to the thermal effect of electric current, as long as the current passing through the fuse exceeds its rated current and reaches the melting current, the fuse will quickly melt, automatically disconnecting the circuit and power supply. This way, strong currents cannot enter the user's home, preventing damage to instruments, appliances, or wires connected to the circuit due to excessive current. When a fuse blows, it cannot be casually replaced with copper or iron wire. If copper or iron wire is used to replace the fuse, due to their high melting points, they will not melt even when strong currents pass through, failing to achieve the purpose of automatically cutting off the current, which is very dangerous. Additionally, when installing a fuse, it is essential to choose one of the appropriate thickness. There are many specifications for fuses, usually indicated by their rated current. For fuses made of the same material, the larger the cross-sectional diameter, the higher the rated current that can pass through. Therefore, when selecting, it is necessary to first calculate the maximum working current through the circuit based on the total wattage of the appliances, ensuring that the rated current of the fuse is equal to or slightly greater than the maximum working current of the circuit. This ensures that the fuse can operate normally and can quickly melt and cut off the circuit when encountering excessive current. If the rated current of the fuse is too high, it will not melt when there is excessive current in the circuit, failing to provide protection, which is no different from using steel or iron wire; if the rated current is too low, the fuse will also blow under normal electrical conditions, causing power outages.
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