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| Safety Measures in Electrical Circuits |
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| An electric fuse is a device which is used to limit the current in an electric circuit. The use of a fuse is to safeguard the circuit and the appliances connected in the circuit from being damaged. |
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Parts of an Electric Fuse |
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Working of a Fuse Wire |
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| Fuse Arrangement |
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| The fuse is a short piece of wire made of a material of high resistance and of low melting point so that it may easily melt due to overheating when excessive current passes through it. Generally an alloy of lead and tin is used as fuse wire. |
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| The fuse wire 'F' is stretched between
the two metallic terminals T1 and T2 in a porcelain
holder. This holder fits into a porcelain socket which is connected to the
live wire of the circuit. |
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| When the current in the circuit exceeds
the specified value due to voltage fluctuations or short circuiting, the
fuse wire gets heated up to the extent that it melts. As a result, a gap is
produced and the circuit breaks. No current flows and the appliance or the
circuit is saved. After eliminating the fault in the circuit, a new fuse
wire of the same current rating is inserted in the holder to complete the
circuit again. |
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| The fuse is always connected to the live
wire of the circuit. If the fuse is connected to the neutral wire then even
when the fuse burns, the appliance remains connected to the live wire and
the appliance may get damaged.. |
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| The fuse is always connected in the beginning of the circuit before any appliance is connected, so that the fuse may melt before the appliance is damaged. |
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| The fuse wire must be of a current rating less than the maximum current which a circuit or an appliance can withstand. |
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