In this of fuse, the breaking capacity is increased by using two or more separate silver elements in parallel. The sizes of the elements are varied so that the elements fuse in a sequence, one after the other. The body is made up of cylindrical ceramic material and is closed by metallic end caps to which the fuse elements are fixed. The fuse elements are surrounded by silica, which acts as the arc quenching medium. An indicator, normally a fine resistance wire, is connected in parallel to the fuse element. In this type of fuse, the whole fault current is not shed immediately due to the usage of more than one fuse element. This construction avoids voltage transients in the circuit.
Advantages of HRC fuses
- When compared to other circuit interrupters of same capacity HRC fuses are the cheaper one.
- Simple and easy to install.
- No maintenance required.
- High breaking capacity.
- They are consistent in performance.
- Their inverse time characteristic makes them much suited for overload protection.
- They are capable of clearing high as well as low currents.
- Quick operation.
- They are capable clearing high as well as low currents.
- During severe faults, an HRC fuse breaks the circuit before the peak current of the fault is reached.