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Materials used as fuse element – Selection of fuse wire - types of fuses – difference between circuit breaker and fuse – why fuse is not used in the neutral – table for sizes of fuse wire.
In electronics and electrical engineering a fuse (short for fusible link) is a type of overcurrent protection device. Its typical component is a metal wire or strip (element) that melts when too much current flows, which interrupts (disconnects) the circuit in which it is connected. Circuit or device failure is often a reason for excessive current. A fuse blows (interrupts excessive current) so that further damage (ie. fire) is prevented. A fuse typically is not intended to protect from the initial cause of overcurrent.
Overcurrent protection devices are an essential part of appliances and of power distribution systems to limit both threats to human life and damage. For example, too much current for too long may cause a wire to overheat, be damaged, or even start a fire. Wiring regulations often define a maximum fuse current rating. Fuses are selected to allow passage of normal current and of excessive current for short periods. And to interrupt what is called a short circuit, overload condition, or fault current.
A fuse was patented by Thomas Edison in 1890 as part of his successful electric distribution system. Edison writes, "The passage of an abnormal electric current fuses the safety-catch and breaks the circuit, as will be understood."