Fuses are safety devices inserted in electrical lighting, heating and power circuits. When a circuit becomes overloaded or shorted, the fuse wire, which is thinner and softer than the main circuit wires, heats and melts, automatically cutting off the electrical supply to the circuit affected — thus minimizing risks of fire and shock. Repair necessities used to be a card of fuse wire and a small insulated screwdriver – nowadays you just need a pack of the relevant amperage fuses together with the screwdriver; these should be stored near the fuse-boxes together with a torch or candles and matches.Before opening the fuse-box, the current must be switched off at the main.Examine all the fuses in the box; the burnt one can usually be identified by a sooty smudge on the white porcelain holder. Loosen the screws in the holder (see image) and remove every piece of the old wire; wipe off the sooty deposit before replacing burnt wire with a new piece of correct strength. The amperage is usually stamped on the side of the porcelain holder-5 amp. for lighting, 10 amp. for heating, and 15 amp. for power. It is dangerous to use wire stronger than the specified amperage, and only fuse wire should be used — not hairpins or old bits of any odd wire.Coil the ends of the new length of wire round the securing screws in the porcelain holder and under the washers, snip off the surplus ends of wire and tighten the screws. The wires should be slightly slack between the two terminals to permit normal cooling contraction after the wire becomes hot — tight wires snap easily. Replace the fuse-holders in the box and switch the current on at the main.
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