This is a
luminous high temperature electric discharge across gab or a joint. The
temperature in an arc can be several thousand degrees. A voltaic are can be
serial or parallel are (shot circuit are). A serial are cannot exist with out
current load and will disappear when the current is turned off. Fire may break
out if the close to the are, from gasses generated by the are or because of hot
piece of metal.
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Ignition due to overcharge will usually need an
amperage that the cable is dimensioned for. Since electric circuit normally are
shelled with 10-20 A fuses, heavy overcharge must be considered to
be a fairly
rare causes of fire in cables.
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Cables
which are neither damaged not exposed to overcharge, can still cause fire. One
just need to coil up the cable a sufficient number of times, or use too much
insulation around the cable, or both Laboratory tests hare shown that ignition
of combustible material may occur in such cases. A one such incident it was
sufficient to coil up the cable direct times sand cover the coil in clothing.
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Loose screw-couplings: Plays with
screw-couplings may be exposed to over heating because of contract failure.
Mechanical damage often occurs in plugs as a consequence of pulling and bending
a conductor a great number of times. This can lead to breaking of the
conducting wires in the plug. This may cause voltaic are, Overheating and Fire.