240.60(B) Violation

[DPW]

We use standard 'Heavy Duty' Square D disconnects (H361,362,363 & H364) with fuses (time delay 'R') for motor applications. Off the shelf, this disconnect accepts Class H fuses. However it will also accept a 'R' fuse.
Recently an inspector pointed this out as a violation of 240.60(B).

In order to comply 240.60(B), does one have to install a fuse rejection kit?
If so, why doesn't the manufacturer offer a disconnect for 'R' type only?

240.60 General.
(A) Maximum Voltage ? 300-Volt Type. Cartridge fuses and fuseholders of the 300-volt type shall be permitted to be used in the following circuits:
(1) Circuits not exceeding 300 volts between conductors
(2) Single-phase line-to-neutral circuits supplied from a 3-phase, 4-wire, solidly grounded neutral source where the line-to-neutral voltage does not exceed 300 volts
(B) Noninterchangeable ? 0?6000-Ampere Cartridge Fuseholders. Fuseholders shall be designed so that it will be difficult to put a fuse of any given class into a fuseholder that is designed for a current lower, or voltage higher, than that of the class to which the fuse belongs. Fuseholders for current-limiting fuses shall not permit insertion of fuses that are not current-limiting.

 

[K8MHZ]

Fuseholders shall be designed so that it will be difficult to put a fuse of any given class into a fuseholder that is designed for a current lower, or voltage higher, than that of the class to which the fuse belongs.

I highlighted a couple key words here.

Class is not rating. It is more like 'type'. The intent of the ruling seems to be the prevention of putting the wrong type of fuse, especially one designed for lighter duty use, into a fuseholder that was not designed (and thus probably not used) for that purpose. A theoretical example of a violation would be a fuseholder listed for use with 480 three phase that plastic automotive fuses would fit into.

A rejection kit is not meant to correct the above as it exists to keep fuses of higher current rating from being used, not a lower one as in bold print, above.

 

[jim dungar]

There is nothing in 240.60(B) that requires you to make the fuse holder only accept the fuse you are using. 240.60(B) says only if the circuit (system) requires a higher rated fuse, must you prevent a lower rated fuse from being inserted.

Many fusible 'safety switches' I have seen have been misapplied. Unless Class R fuse clips are installed, or the fuse holders are moved to the Class J position, fusible devices are usually only rated for 10kA short circuit amps.