Class 2 Low Voltage Lighting wiring

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klive

Member
Location
Carlsbad, CA
Pardon my intrusion into this professional forum, but I have question about NEC requirements for low voltage lighting. My company has developed some new 24v DC LED products that are quite thin and can be mounted on walls and ceilings for a "flush" look. We would like to know if the NEC allows professional installers to run CL2 rated cable on drywall surfaces to connect the sources and then have it covered by a thin layer of plaster. This is all on the load side, of course. We have seen examples of flat tape wire being embedded this way for A/V installations, but wonder if it also can be done for lighting and with regular CL2 cable.

Thanks in advance
 

hbiss

EC, Westchester, New York NEC: 2014
Location
Hawthorne, New York NEC: 2014
Occupation
EC
I don't believe there is any prohibition against embedding CL2 wiring but my opinion is that the installation method you propose is a pretty bad way to do it. It has to be more costly and labor intensive than fishing the wiring. Unless somebody makes a ribbon wiring method (and even then) you are going to have a heck of a job skim coating everything to cover it.

-Hal
 

klive

Member
Location
Carlsbad, CA
I don't believe there is any prohibition against embedding CL2 wiring but my opinion is that the installation method you propose is a pretty bad way to do it. It has to be more costly and labor intensive than fishing the wiring. Unless somebody makes a ribbon wiring method (and even then) you are going to have a heck of a job skim coating everything to cover it.

-Hal

Thanks for the response, that's encouraging. Our thinking is that there are situations where access to the space above the sheetrock is difficult or even impossible, and that this would be way to get a recessed lighting look without actually having to cut a hole. (Our sources are thinner than the bezel on a normal "can" light). Just looking for niches in the market we can fill. Actually tried coating over some 18 gauge on a scrap piece of wallboard with plaster, and were pleasantly surprised how well it disappeared. Probably take some convincing to get people to try it in an installation. But that's what marketing weasels like me are for.

Thanks again
 

mwm1752

Senior Member
Location
Aspen, Colo
725.24 Mechanical Execution of Wor k
Class 1, Class 2, and Class 3 circuits shall be installed in a neat and workmanlike manner. Cables and conductors installed exposed on the surface of ceilings and sidewalls shall be supported by the building structure in such a manner that the cable will not be damaged by normal building use. Such cables shall be supported by straps, staples, hangers, cable ties, or similar fittings designed and installed so as not to damage the cable. The installation shall also comply with 300.4(D).
 

hbiss

EC, Westchester, New York NEC: 2014
Location
Hawthorne, New York NEC: 2014
Occupation
EC
300.4(D) is the 1-1/4" rule which doesn't apply to cable run on the surface. But is cable run on the surface and covered with a thin layer of joint compound now concealed? (If you can't see it it's concealed.) 725.24 certainly does make a good argument against wire embedded in joint compound as being considered adequately protected from normal building use like hanging pictures.

Like I said, I wouldn't do it.

-Hal
 

tom baker

First Chief Moderator
Staff member
There was a 2008 NEC change on this product....
Article 382 has been revised to incorporate provisions for concealed nonmetallic
extensions. A new definition of this type of concealable nonmetallic extensions has been
added in 382.2. The article has been expanded to include specific product listing
requirements in 382.6. Section 382.10 and 382.12 covering Uses Permitted and Uses Not
Permitted have been revised and expanded to incorporate requirements and restrictions
for concealable nonmetallic extensions. A new Part III has been added to provide specific
construction specifications for concealable nonmetallic extensions.
 
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