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Thread: In-Wall Speaker Wire

  1. #1

    Default In-Wall Speaker Wire

    I know that to directly install speaker wire through studs in my walls, it needs to be rated CL-2, at least. If conduit is used to run this wire, does that eliminate the need for the CL-2 rated speaker wire?

    I was under the impression that the presence of conduit does not change the CL-2 requirement, but I'd like a definitive answer.

    Scott Sabin

  2. #2


    I am a bit confused in what you seek. A speaker wire may be class 2 or class 3. Either is allowed to be a jacketed cable ran directly in the sides or crawls space or attic. Only limitations is exposure to power cables of class 1 or 120 volt wiring etc. The use of conduit can only do two things for you. The conduit may be use to separate the higher voltage wires from the class 2 or 3 low voltage wires. The conduit may be used to protect class 2 o3 wires from physical damage.

    Wiring class 2 or 3 wiring is almost unlimited in stud spaces with the exception of wiring inside a plenum which would require plenum class 2 or 3 wiring.

    Conduit does not change the status of class 2 or class 3 speaker wires other than mentioned above.

    What is it that you wanted conduit to do for you?



  3. #3


    This is really a simple question, and not too deep. Radio Shack carries speaker wire with several characteristics listed, one of which is "in-wall use: NO". This is your basic lamp cord wire, and it does not have any indication that it is rated CL-2. They do also carry wire which is labelled "in-wall use: YES", but this wire isn't available in as heavy a gage.

    My original question assumed that some low-voltage speaker wire was rated CL-2 (or higher), and some did not meet this criteria. Is this not true? Is all speaker wire CL-2 by default, and if so, why does some wire explicitly list the CL-2 rating while other wire does not (i.,e Home Depot wire)? Based on that assumption, the question was whether conduit allowed you to use non-CL2 rated speaker wire in walls. Essentially, using the 12 AWG lamp cord for speaker wire.
    Scott Sabin

  4. Default

    Very interesting. Three years ago, when we built our house, I ran standard 16 gauge speaker wire all over the place, as well as added several extra phone and cable jacks, to save the bucks the builder wanted for these extras.
    I discussed my plans with our builder, ran my speaker wire, and the electrical inspection passed without problem. I don't believe my speaker wire had any special rating.

  5. #5


    Did you use the "zip" or lamp cord type of speaker wire found at Home Depot?

    I personally wouldn't feel that this type of wire is any more dangerous than other types of speaker wire, but was assumed that code didn't allow it since the Radio Shack signs and Home Depot signs do explicitly call out some of their wire as capable of being installed in walls.

    Maybe I shouldn't worry about it, or call my inspector to get his take on it. That always seems to be good advice, but in my township, he is only in the office a couple hours a week.
    Scott Sabin

  6. Default

    I got this wire in a 100 foot spool at our local home improvement store. It was relatively inexpensive. I'll check the spool when I get home, and see if it just happened to be labled a certain way, but I'm quite sure it was not. It was not lamp cord, actually called speaker wire, and has a rather nice insulation. Not quite Monster Cable quality, but better than lamp cord.
    I'll let you know what I discover.

    My builder was not in the least bit worried when I told him my plans. I even ran the wire through some of the existing romex holes when I could. The speaker wire does not run along side any romex, though. As I mentioned earlier, no problems whatever with the electrical inspection.


  7. Default

    Here is the details on the wire.

    The spool does have a label. It was actually a 250' spool of 16/2 clear speaker CL2 UL.

    The spool has a UL listing on the sticker as well.
    Power-Limited circuit cable. Form 3 communications cable.
    For use in class 2 power-limited circuits and communications.
    type GMH.

    None of that means anything to me, I was just looking for 16 gauge speaker wire, and this is what they had in the length I wanted.

  8. #8


    Class two and class 3 wiring is very forgiving in wiring methods. You should be fine with what you are discribing. However I thought I would include what the intent and concern of the NEC concerning this type wiring. Might be of some help. Biggest concern is toxic smoke of the insulation on this type wire if on fire and any increase of spead of fire concerning this type wiring. See if the copied section below helps;

    725.71 Listing and Marking of Class 2, Class 3, and Type PLTC Cables.
    Class 2, Class 3, and Type PLTC cables installed as wiring within buildings shall be listed as being resistant to the spread of fire and other criteria in accordance with 725.71(A) through (G) and shall be marked in accordance with 725.71(H).

    (E) Other Wiring Within Buildings. Cables installed in building locations other than those covered in 725.61(A) through (D) shall be as described in any of (1) through (6). Abandoned cables in hollow spaces shall not be permitted to remain.
    (1) Type CL2 or CL3 shall be permitted.
    (2) Type CL2X or CL3X shall be permitted to be installed in a raceway or in accordance with other wiring methods covered in Chapter 3.
    (3) Cables shall be permitted to be installed in nonconcealed spaces where the exposed length of cable does not exceed 3 m (10 ft).
    (4) Listed Type CL2X cables less than 6 mm (0.25 in.) in diameter and listed Type CL3X cables less than 6 mm (0.25 in.) in diameter shall be permitted to be installed in one- and two-family dwellings.
    (5) Listed Type CL2X cables less than 6 mm (0.25 in.) in diameter and listed Type CL3X cables less than 6 mm (0.25 in.) in diameter shall be permitted to be installed in nonconcealed spaces in multifamily dwellings.
    (6) Type CMUC undercarpet communications wires and cables shall be permitted to be installed under carpet.

    Hope this helps


  9. #9

    Default Distance from AC Lines?

    What does the NEC say about running speaker wires (CL2 or CL3) next to AC lines within wall cavities? I remember reading somewhere about a distance of 2", but I'm not sure what that means.

    Does this mean that a speaker wire can not be run closer than 2" from an AC cable, even say if the two cables cross perpendicular to one another?

    Also, I assume I cannot pass a speaker wire and an AC cable through the same hole drilled through a stud or joist. Is this true?

    Please advise, as I'm going to be running my speaker wire in my media room project this weekend.


  10. #10


    OK, the original question still stands, as nothing really has been cleared up.

    Thanks for checking on your wire, Dave, but that wire is listed as CL-2.

    My original question can be broken into two easy questions:
    1) can speaker wire that is NOT listed as CL-2 be used within walls?
    2) If the answer to 1 is no, does the use of conduit allow such wire to be used in walls?

    I was under the impression that both answers are "no", but I'd like to know for sure.

    I suspect the CL-2 rating means that the wire has passed some test which means it is capable of withstanding some voltage level for so much time. I think CL-2 has to be capable of 150V and CL-3 300V, or something like that.
    Scott Sabin

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