Fuse (electrical)
Breaking capacity

The breaking capacity is the maximum current that can safely be interrupted by the fuse. This should be higher than the prospective short-circuit current. Miniature fuses may have an interrupting rating only 10 times their rated current. Fuses for small, low-voltage, usually residential, wiring systems are commonly rated, in North American practice, to interrupt 10,000 amperes. Fuses for commercial or industrial power systems must have higher interrupting ratings, with some low-voltage current-limiting high interrupting fuses rated for 300,000 amperes. Fuses for high-voltage equipment, up to 115,000 volts, are rated by the total apparent power (megavolt-amperes, MVA) of the fault level on the circuit.

Some fuses are designated high rupture capacity (HRC) or high breaking capacity (HBC) and are usually filled with sand or a similar material.

Low-voltage high rupture capacity (HRC) fuses are used in the area of main distribution boards in low-voltage networks where there is a high prospective short circuit current. They are generally larger than screw-type fuses, and have ferrule cap or blade contacts. High rupture capacity fuses may be rated to interrupt current of 120 kA.

HRC fuses are widely used in industrial installations and are also used in the public power grid, e.g. in transformer stations, main distribution boards, or in building junction boxes and as meter fuses.

In some countries, because of the high fault current available where these fuses are used, local regulations may permit only trained personnel to change these fuses. Some varieties of HRC fuse include special handling features.
oulipo:avoid_letter[t]