Tag: electric current and its effects

Nowadays MCB in low voltage electrical network is commonly used instead of fuse. The fuse may not sense the overcurrent but the miniature circuit breaker does it in a more reliable way. MCB is much more sensitive to over current than fuse. Handling a MCB is electrically safer than a fuse.

Fuse is a piece of a wire of material with a very low melting point. When a high current flows through the circuit due to overloading or short circuit, the wire gets heated up and melts.

A fuse is an electrical safety device (a component) that removes electrical current from an electrical circuit when the current in the electrical circuit is too high.

The fuse element is made of zinc, copper, silver, aluminum, or alloys to provide stable and predictable characteristics. The fuse ideally would carry its rated current indefinitely, and melt quickly on a small excess.

A fuse wire has a HIGH resistance & LESS melting point. so that it can protect the electric appliances at home by undergoing melting due to excess heat produced because of high resistance. 

Melting point of a fuse wire is low. So by any chance if high current flows through the circuit, the fuse melts because of heat produced in the circuit beyond a permissible limit. A fuse must have high resistance so as to oppose the current flowing through it beyond a safe limit.

A fuse is a type of low resistance resistor that acts as a device to provide over-current protection, of either the load or source circuit.
Where several fuses are connected in series, it is desirable to blow (clear) only the fuse (or other over-current device) electrically closest to the fault. Hence, when two fuses are in series the current rating is simply the current rating of each fuse i.e. in series, the combination acts as a fuse of rating 10 A
When two fuses are in parallel the current rating is simply twice the current rating of each fuse, hence, in parallel, the combination acts as a fuse of rating 20 A.