When used in distribution circuits, fuses can be cascaded in rating to isolate certain parts of the
distribution circuit while leaving the other parts unaffected.
This is an essential function of a fuse protected distribution circuit to prevent unwanted power outages due to a local fault at
another location on the circuit.
Under IEC60269 guidelines, fuses made to this standard can be selected using a 1 to 1.6 ration to achieved discrimination.
Fuse selectivity is relatively easy to achieve compared to other protective devices which can be difficult to coordinate..