Unprotected/unsheathed NM wire

[Josef F]

First, as an architect, I do not have near the depth of NEC 2012 understanding that I would like.

During a property condition assessment, an electrical contractor mentioned that in a commercial building, extension cords, to light fixtures or otherwise, as well as NM cable strapped to the exposed bar joists and running to quads (where the extension cords were) would need to be redone as it's not to code.

Back in the office, when relaying this information, my electrical engineers did talk about using EMT to the existing quad locations (replacing with metal boxes, etc) but said we wouldn't need to run further extensions of EMT and/or new quads, because no where in the NEC does it restrict length of extension cords.

Then, on another project, it comes up that the owner would like to suspend some fixtures from the open structure roughly 15 feet above the plane of the light fixtures. Again, the desire would be to run EMT to some boxes, but the cord (hard-wired in this case) down to the light fixture would be exposed.

Can any of you wonderful forum regulars provide some expertise and NEC code locations that govern what I, as an architect, can expect or am allowed to do when trying to hang or attach my lights to exposed structures in business, Assembly, and Mercantile occupancies (per IBC 2012 definitions). I'll also be asking some of the electrical engineers this question over lunch, but as I only hang out with the EITs, they don't always catch everything and I'm assuming the experience here will be more senior.

Thanks,

 

[JFletcher]

Welcome.

The NEC runs in 3 year cycles; the latest is the 2017. So there is also a 2014, 2011, and 2008, etc, but no 2012 - there IS a 2012 IRC and IBC, which is what you might be thinking of/referencing. (eta: I see you mentioned the 2012 IBC later in your post).

Extension cords cannot be used as permanent wiring; 400.8.

NM can be run exposed in certain conditions. As far as your lights, typically they would be fed with MC cable. If the lights have a factory supplied cord, that is allowed and not the same thing as extension cord.

I believe you can also use RMC to support lights up to 20' from the box, tho I dont have a code section for that at the moment.

 

[kwired]

400.7 and 400.8 lists general rules of where flexible cords can and can't be used.

As mentioned if the luminaire comes with cord attached, it likely is listed that way and can use it. It typically will terminate into a outlet box directly above the luminaire or in some component that is a part of the luminaire.

NM cable is covered in art 334. 334.10 and 334.12 lists general rules of where NM cable can and can't be used.

In your applications it is very likely if NM cable is used that it must be concealed within at least a 15 minute finish.

 

[LarryFine]

During a property condition assessment, an electrical contractor mentioned that in a commercial building, extension cords, to light fixtures or otherwise, as well as NM cable strapped to the exposed bar joists and running to quads (where the extension cords were) would need to be redone as it's not to code.

Also, keep in mind that the code applicable to existing installations is the code that was in force at the time of the installation.