How can fuses provide protection?

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Fuses are made from metals such as lead, tin, antimony, and zinc of specific specifications; they serve as protective devices installed in electrical circuits. They allow only normal current to pass through. When a short circuit or overload occurs in the circuit, the heat generated by the current raises the temperature above the fuse’s melting point, causing it to melt and thus interrupt the circuit. This helps to ensure the safety of the circuits and electrical equipment, preventing fires that could result from excessive currents in the circuit. To ensure the fuse functions properly as a protection device, the following points should be observed: ● Do not use overly thin fuses; thin fuses are prone to being blown by normal current flow, resulting in unnecessary power outages ； ●Fuses that are suitable for the total power of the electrical equipment must be selected and used; the blowing current of such fuses is usually 1.5–2.0 times the rated current. If the total power consumption of all electrical appliances in a household during normal use exceeds 1100 watts, a fuse of 5 amperes and diameter 0.98 millimeters, type 20, will suffice. When the current rises to between 7.5 and 10 amperes, the fuse will automatically blow, thereby providing protection. ●If the fuses selected and used meet the specifications yet fuse blowing occurs frequently, it indicates a problem with the electrical wiring or electrical equipment; it is necessary to call an electrician promptly to identify the cause and eliminate the hazards. Never replace fuses casually or use wires such as copper or iron in their place. This post was last edited by limingshuguang on 2007-11-27 09:08.]