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Most multibay enclosures interlock the doors to prevent access unless the main disconnect is off or a tool-operated override is actuated by
qualified service personnel. The disconnect itself is capable of being locked off. (I'm referring to typical NEMA 12 enclosures housing
480-3-60 devices such as starters, drives, etc.)
Is anyone aware of restrictions (OSHA, NEC, NFPA79, etc) AGAINST locking the enclosure doors, irrespective of the disconnect? Or to put
it another way, if padlocks, for example, were installed on the doors to prevent access, would this be a violation? If the disconnect is off,
access would still be denied unless someone was authorized to unlock it. What if (however unlikely) a fire should occur within such an enclosure and the locks prevented access to put it out? I think it is a bad idea, but cannot think of a code that specifically states you cannot lock an enclosure in this manner. Is the type or method of locking defined by code?
My suggestion was to install solenoid locks (similar to those manufactured by Hoffman) that energize when the disconnect is on, and
keyswitch overrides to allow entry by service personnel. If a fire should occur, the first thing one would do is turn off the disconnect
which would then allow access by any person with a fire extinquisher.
Feedback?
qualified service personnel. The disconnect itself is capable of being locked off. (I'm referring to typical NEMA 12 enclosures housing
480-3-60 devices such as starters, drives, etc.)
Is anyone aware of restrictions (OSHA, NEC, NFPA79, etc) AGAINST locking the enclosure doors, irrespective of the disconnect? Or to put
it another way, if padlocks, for example, were installed on the doors to prevent access, would this be a violation? If the disconnect is off,
access would still be denied unless someone was authorized to unlock it. What if (however unlikely) a fire should occur within such an enclosure and the locks prevented access to put it out? I think it is a bad idea, but cannot think of a code that specifically states you cannot lock an enclosure in this manner. Is the type or method of locking defined by code?
My suggestion was to install solenoid locks (similar to those manufactured by Hoffman) that energize when the disconnect is on, and
keyswitch overrides to allow entry by service personnel. If a fire should occur, the first thing one would do is turn off the disconnect
which would then allow access by any person with a fire extinquisher.
Feedback?