300.12 Violation?

[120good277bad]

Hey everyone. I'm a lead electrician at a small commercial company and I'm having a conflict with the GC regarding raceway. I'd appreciate some thoughts, help, or additional codes that could help me make my case. Here is my scenario.

There is a 12"x16"x4" pull box that has 1-1/2" EMT coming into the top of it from a main disconnect. The pull box, per the GC, MUST be recessed in this equipment room (this is for an x-ray machine). The problem is we don't have enough of a gap to bring flex cleanly out of the wall. So the GC is insisting that I punch a hole in the cover of this pull box, and then install a connector and flex on the cover. I'm pulling 2AWG through this box and into a Power Distribution Unit that will be sitting on the floor. Not only will this look atrocious, but to me it makes accessing the box over complicated and in violation of 300.12 which states that Raceways have to maintain mechanical continuity. Once that cover comes off, it's not longer mechanically continuous. Am I correct in my assertion here? Is there any other codes that would help me make my case? I already tried to simply surface mount the box and they're insisting I cant because of aestetics even though this is an equipment room.

 

[kwired]

My preference would be deeper box so you can enter with both concealed raceways as well as the exposed flex, but my guess is they don't like that either.

I think at very least you might need a bonding jumper to cover or to a bonding bushing on your flex connector to assure bonding of the cover and flex connector.

 

[augie47]

As I read 300.12 it would cover the conduit/raceway runs TO the box and no apply to your situation.
As to aesthetics, the GC may be cautious what he asks for

 

[LarryFine]

Can you punch through a stud to either side and bring your feed out through the cover of a smaller box, or use another appropriate method of bringing a cable out of a wall?

 

[petersonra]

Hey everyone. I'm a lead electrician at a small commercial company and I'm having a conflict with the GC regarding raceway. I'd appreciate some thoughts, help, or additional codes that could help me make my case. Here is my scenario.

There is a 12"x16"x4" pull box that has 1-1/2" EMT coming into the top of it from a main disconnect. The pull box, per the GC, MUST be recessed in this equipment room (this is for an x-ray machine). The problem is we don't have enough of a gap to bring flex cleanly out of the wall. So the GC is insisting that I punch a hole in the cover of this pull box, and then install a connector and flex on the cover. I'm pulling 2AWG through this box and into a Power Distribution Unit that will be sitting on the floor. Not only will this look atrocious, but to me it makes accessing the box over complicated and in violation of 300.12 which states that Raceways have to maintain mechanical continuity. Once that cover comes off, it's not longer mechanically continuous. Am I correct in my assertion here? Is there any other codes that would help me make my case? I already tried to simply surface mount the box and they're insisting I cant because of aestetics even though this is an equipment room.

IMO - The pull box is not a raceway so there is no issue of mechanical continuity of a raceway.

 

[roger]

Usually the xray manufacturer will have their own installation drawings specifically calling out boxes, covers, raceway lengths, etc.... I would think there would be a lead lined envelope that would have to maintained and for this reason a lot of PDU boxes and disconnects are surface mounted.

 

[roger]

Usually the xray manufacturer will have their own installation drawings specifically calling out boxes, covers, raceway lengths, etc.... I would think there would be a lead lined envelope that would have to maintained and for this reason a lot of PDU boxes and disconnects are surface mounted.

Back to the manufacturers design drawings, these rooms are usually (at least the many I have done) listed as an assembly and the NEC does not govern the whole installation, for example, by design there may be flexible cords installed in conduits.

 

[jap]

This is a pretty common installation for an x-ray room.

We've always used flush mount enclosed circuit breakers for this type of install, not surface mount.

For the disconnect that is.

JAP>

 

[120good277bad]

Thanks everyone for your responses. They're very helpful. I think I'll end up running flex out of the bottom and then sending it back up the wall and out. Too many penetrations in the box as it is.

What I'm gathering here is that even though it's absolutely abhorrent engineering to have that connector and flex coming from the cover of the pullbox, it's not actually against any codes? I'm tearing through my 2017 edition like a madman.

 

[kwired]

Thanks everyone for your responses. They're very helpful. I think I'll end up running flex out of the bottom and then sending it back up the wall and out. Too many penetrations in the box as it is.

What I'm gathering here is that even though it's absolutely abhorrent engineering to have that connector and flex coming from the cover of the pullbox, it's not actually against any codes? I'm tearing through my 2017 edition like a madman.

I don't think there is any violation. Unless the purpose of the box is for that particular wiring method transition and nothing else, I absolutely hate it when people make such extensions off a box cover.

 

[acrwc10]

you could throw 110.12 out and see if it sticks.

 

[roger]

you could throw 110.12 out and see if it sticks.

Don't think so for more than one reason. The big one being it isn't really enforceable and the second is as I said before, these rooms are assemblies and besides the feeder, the disconnect, receptacles, and lighting, the components in the room are part of a listed assembly and are not under the NEC. For example, there may be exposed accordion type MV (50 KV or more) cables suspended and traveling with a piece of equipment, the chest board will probably have open cables, etc ..., parts of these rooms are not and can not be NEC compliant. IOWs, the room and equipment is a listed machine.