ECN Forum
Posted By: GETELECTRIC fuse type - 05/03/05 07:48 PM
Why would the inspector ask for type hrc fuses for an incoming service on a multiple dwelling unit.
Posted By: Tony Moscioni Re: fuse type - 05/04/05 06:47 PM
The excellent current limiting characteristics of fast-acting HRCI-J fuses limits damage to equipment and installations by the thermal and magnetic energy associated with a large short-circuit fault current.

and;

When the short-circuit rating of a panelboard depends upon the use of a specific overcurrent device ahead of the panelboard, the panelboard in addition to the marking required in (b) shall be marked with the following, or equivalent:
WHEN PROTECTED BY _______ A MAXIMUM HRC _______ FUSE OR (MANUFACTURER'S NAME AND TYPE DESIGNATION) CIRCUIT BREAKER RATED NOT MORE THAN _______ A, THIS PANELBOARD IS SUITABLE FOR USE ON A CIRCUIT CAPABLE OF DELIVERING NOT MORE THAN _______ A RMS SYMMETRICAL, ______ V MAXIMUM,

Tony Moscioni
Electrical Inspector
Electrical Safety Authority
© ECN Electrical Forums