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Electrical Faults that May Cause FireShort circuits. If the insulation separating two electrical conductors breaks down, a abort circuit occurs. Instead of following its normal path, the current flows from one conductor to the other. Electrical resistance being low, a heavy current flows and causes intense local heating. The conductors become overloaded electrically, and they may become dangerously overheated unless the circuit is broken. If the fuse or circuit breaker fails to operate, fire can result and spread to nearby combustible material. Conductor overloading. When too large electrical load is placed on a circuit, an excessive amount of current flows and the wiring overheats. The temperature may become high enough to ignite the insulation. The fuses and circuit breakers installed in electric circuits will prevent this condition. However, if these safety devices are not maintained properly, their failure may result in a fire. Arching. An arc is pure electricity jumping across a gap in a circuit. In this case there is intense heating in the arc. The electrical strength of the arc and amount of heat produced depend on the current and voltage earned by the circuit The temperature may easily be high enough to ignite any combustible material near the arc, including insulation. The arc may also fuse the metal of the conductor. Then, hot sparks and hot metal may be thrown about, and set fire to other combustibles.
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