Disconnecting Means Within Site

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ed downey

ed downey

Senior Member
Location
Missouri
I have a project that has a 400A 480V 3 Phase feeder to an electric boiler that the room is physically too small to install a 400A disconect switch and have proper clearances. Can we use 430.102(B) for our exception to include a locakable device on the molded case circuit breaker? I am not sure if you consider an electric boiler as a motor or if there is another article that is better to represent the exception I am looking for.
Thanks,
-Ed
 
Re: Disconnecting Means Within Site

The full answer depends on the use of the boiler. If it is for space heating it falls under 424; if it is for other processes it falls under 427.

Both Articles discuss disconnecting means both with and without motors integral to the boiler.

I'd look at 424.19 or 427.55 as applicable.
 
Re: Disconnecting Means Within Site

What do you think are the proper clearances? I don't think the 3' rule applies because I don't see any reason why someone would have to work on this disconnect while it is "hot".

I know others feel different.

Steve
 
Re: Disconnecting Means Within Site

Per article 110.26 you need 3 feet of clearance for equipment requiring service, examination, adjustment, or maintenance while energized.
I have read many articles about this and people even talk about you need 3 feet of clearance for ac disconnects which could only be 30-amp. Talk about one that is questionable.
Joseph.
 
Re: Disconnecting Means Within Site

This is what I feel 110.26(A) should say:

Working space for equipment switchboards, panelboards, industrial control panels, meter socket enclosures, and motor control centers operating at 600 volts, nominal, or less to ground shall comply with the dimensions of 110.26(A)(1), (A)(2), and (A)(3) or as required or permitted elsewhere in this Code.
 
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