Approved wiring for under-cabinet lights

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411.5 Secondary Circuits

(D) Insulated Conductors. Exposed insulated secondary
circuit conductors shall be of the type, and installed as, described
in (1), (2), or (3):

(1) Class 2 cable supplied by a Class 2 power source and
installed in accordance with Parts I and III of Article
725.

(2) Conductors, cord, or cable of the listed system and installed
not less than 2.1 m (7 ft) above the finished floor
unless the system is specifically listed for a lower installation
height.

(3) Wiring methods described in Chapter 3
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This is what you are talking about but it really has nothing to do with whether you can or can't substitute NM as a CL2 cable. All (3) relates to is the requirement for the use of a Class 1 power source that must use a Chapter 3 wiring method.

If you look at the hierarchy charts in 725, a CL3 cable can substitute for a CL2 cable. If you project that further, a Class 1 cable can substitute for everything- CL3 and CL2.

A CL3 or CL2 circuit doesn't require splice boxes and that's the overriding factor as long as you are using a cable that is listed for installation within walls and ceilings.

To me this issue is no different than using data cable for thermostat or doorbell wiring.

My interpretation of course, since the Code is silent on this issue.

-Hal
 
LarryFine said:
I usually use jacketed in-wall-rated speaker wire. It's available in different gauges and is colored for D.C.
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I think this is the wire my EC friend ended up going with. We'll see if he passes inspection. He was told by an EI that the jacket had to be marked with the wire size, have a UL listing and insulation rating (in this case 300V)
 
725.130(B) doesn't require the use of a listed Class 2 cable on the load side of a Class 2 power source. Skimming through the requirements referenced in 725.130(B), it appears to me that NM cable would meet them. If that is correct, using a Class 2 power source with NM cable with open splices would meet 411.5(D)(1).

Cheers, Wayne
 
wwhitney said:
725.130(B) doesn't require the use of a listed Class 2 cable on the load side of a Class 2 power source. Skimming through the requirements referenced in 725.130(B), it appears to me that NM cable would meet them. If that is correct, using a Class 2 power source with NM cable with open splices would meet 411.5(D)(1).

Cheers, Wayne
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What about 725.133 and 725.135?
 
wwhitney said:
What part of 725.135 do you see as a problem?

Cheers, Wayne
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It seems to me that Class 2 cables in one and two family dwellings would be limited to those listed in 725.135(M)

725.135 Installation of Class 2, Class 3, and PLTC Cables.
Installation of Class 2, Class 3, and PLTC cables shall comply
with 725.135(A) through (M).

(M) One- and Two-Family Dwellings. The following wires and
cables shall be permitted to be installed in one- and two-family
dwellings in locations other than the locations covered in
725.135(B) through (I):
(1) Types CL2P, CL3P, CL2R, CL3R, CL2, CL3, and PLTC
wires and cables
(2) Type CL2X wires and cables less than 6 mm ( 1∕4 in.) in
diameter
(3) Type CL3X wires and cables less than 6 mm ( 1∕4 in.) in
diameter
(4) Communications wires and Types CL2P, CL3P, CL2R,
CL3R, CL2, CL3, and PLTC cables installed in the following:
a. Plenum communications raceways
b. Plenum cable routing assemblies
c. Riser communications raceways
d. Riser cable routing assemblies
e. General-purpose communications raceways
f. General-purpose cable routing assemblies
(5) Types CL2P, CL3P, CL2R, CL3R, CL2, CL3, CL2X, CL3X,
and PLTC wires and cables installed in raceways recognized
in Chapter 3
(6) Type CMUC undercarpet communications wires and
cables installed
 
There is no 411.5(D)(1) in the 2017

411.5 Specific Location Requirements.
(A) Walls, Floors, and Ceilings. Conductors concealed or
extended through a wall, floor, or ceiling shall be in accordance
with (1) or (2):
(1) Installed using any of the wiring methods specified in
Chapter 3
(2) Installed using wiring supplied by a listed Class 2 power
source and installed in accordance with 725.130
(B) Pools, Spas, Fountains, and Similar Locations. Lighting
systems shall be installed not less than 3 m (10 ft) horizontally
from the nearest edge of the water, unless permitted by Article
680.
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packersparky said:
(M) One- and Two-Family Dwellings. The following wires and
cables shall be permitted to be installed in one- and two-family
dwellings in locations other than the locations covered in
725.135(B) through (I):
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That language is not mandatory, it is permissive. The list given is not exhaustive.

Cheers, Wayne
 
wwhitney said:
That language is not mandatory, it is permissive. The list given is not exhaustive.

Cheers, Wayne
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That's why I copied the first part in 725.135.

725.135 Installation of Class 2, Class 3, and PLTC Cables.
Installation of Class 2, Class 3, and PLTC cables shall comply
with 725.135(A) through (M).


725.135(B) through (M) all say "shall be permitted".
 
In the 2017 version, 725.135 uses "shall comply", 725.135(A) uses "shall be listed", and 725.135(B)-(M) uses the "shall be permitted" language. In my opinion the "shall comply" language at the start of 725.135 doesn't turn the permissive "shall be permitted" language in 725.135(B)-(M) into mandatory language. Only 725.135(A) is mandatory, and NM cable is listed.

As a practical matter, does a cable type such as CL2X have any requirements that wouldn't be met by NM cable?

Cheers, Wayne
 
wwhitney said:
In the 2017 version, 725.135 uses "shall comply", 725.135(A) uses "shall be listed", and 725.135(B)-(M) uses the "shall be permitted" language. In my opinion the "shall comply" language at the start of 725.135 doesn't turn the permissive "shall be permitted" language in 725.135(B)-(M) into mandatory language. Only 725.135(A) is mandatory, and NM cable is listed.

As a practical matter, does a cable type such as CL2X have any requirements that wouldn't be met by NM cable?

Cheers, Wayne
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If that is the case and none of the cable types in 725.135(B) through (M) are mandatory, I could install NM cable for a Class 2 circuit in a riser in any building (for example).
 
packersparky said:
If that is the case and none of the cable types in 725.135(B) through (M) are mandatory, I could install NM cable for a Class 2 circuit in a riser in any building (for example).
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Seems like the "shall be permitted" revision in 2014 screwed up the meaning of 725.135. You are probably reading it the way it is intended, but I don't think the language actually says what is intended.

In 2011, the comparable section is 725.154, which says "shall comply with any of the requirements described in 725.154(A) through (I)." 725.154(A) says, for example "(A) Plenums. Cables installed in ducts, plenums, and other spaces used for environmental air shall be Type CL2P or CL3P." Very clear and direct language.

Cheers, Wayne
 
Dennis Alwon said:
I still don't see how that allows nm run with open splices. Chapter 3 wiring methods do not allow that
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(2017) 411.6(D)(1) doesn't require a Chapter 3 wiring method, it just requires a Class 2 cable supplied by a Class 2 power source.

So the question is what is a Class 2 cable and can NM cable be used as a Class 2 cable? I can't find a definition of "class 2 cable". Does it necessarily mean one of the cable types listed in (2017) 725.179? The wording of 725.130(B) seems to leave the door open to other cable types.

This leaves me a bit confused.

Cheers, Wayne
 
Article 725

Article 725

I have a novel idea. How 'bout a complete re-write of 725. This thing has turned into a convoluted mess. And with all the new products limited power products that are coming out at furious pace we all are going to be referring to this more often. Take for example the practice of reclassifying a class 2 circuit to class 1. Wildly misunderstood and misapplied.
 
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