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I want to wire up a recessed light in a finished closet ceiling, and link it up to a switch on one of the walls of the closet.

To reach the wall from the fixture, I need to cross two joists. There’s a 1/2" gap below the joists created by the steel/aluminum furring/strapping. The cable fits in that gap without pinching.

Is using NM cable ok for that, or does it need to be conduit/armored cable —- since it’s so close to the finished surface?

I was thinking I’d drill through the top plate (double wooden 2x4), bend a rounded 90°, and fish across, threading the cable between furring and joists. I think I can get away with not crossing over a metal furring rail (which you typically have to do if you’re going "diagonally" in the lattice).

furring channels
Illustrates the path my cable would take (in green), if this was the closet ceiling. Just picture a layer of 5/8" finished drywall under all of that

I’m in Vancouver, BC, Canada

  • Joists are wooden
  • studs are wooden
  • top plate is wooden
  • just the furring is metal

Including the relevant section of my local code. This is Section 12 of the Canadian Electrical Code (although 2015). This section is specifically on non-metallic cable.

12-510 to 12-514

Unless there's a specific provision that I'm missing, it would seem that the cable needs to be protected if it runs across the face joists. It also says that it can also be fished if it's impractical to support the cable, but maybe not across joists, but it's not explicitly mentioned.

enter image description here

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  • Shouldn't need to be in conduit, and you certainly won't be fishing conduit through a finished wall! I'd let the experts chime in, though, before accepting this as gospel.
    – FreeMan
    Feb 14, 2023 at 13:07

1 Answer 1

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Code-wise in Canada, I don't know.

Practically: If you have steel framing that you're trying to fish through or across, I would strongly advise using AC or MC or MC-lite cable with a flexible metallic armor rather than plastic-coated NM. Steel framing has sharp edges that will slice insulation like a razor blade if the cable is not protected with bushings where it passes through, and you can't do that when fishing.

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    My read on the question (albeit suspect, as I haven’t had much coffee) was that he wasn’t fishing past or across metal — just using the space under the joist created by the metal. Maybe OP can clarify? Feb 14, 2023 at 14:34
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    i might be able to clarify with a picture. the furring runs perpendicular to the joists (of course), but there are exposed screw tips poking out where drywall screws were used. that could certainly slice the nm sheath. as for the top plate, it’s wooden, and i don’t see how AC/lite cable is needed there.
    – init_js
    Feb 14, 2023 at 17:22
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    re-reading your answer… all framing is wooden, not steel. just the furring is steel/aluminum.
    – init_js
    Feb 14, 2023 at 17:41
  • also, if you would be so kind to generalize your answer a bit more… i’ve also noticed that in a separate room, my existing cables that run between potlights parallel to joists are not armored, they’re just loose resting directly on drywall, not attached. this is technically a different question, but I’m wondering if your advice would also apply, were I running cables in the other direction instead
    – init_js
    Feb 15, 2023 at 7:40
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    12-516(2), "or along" gives the inspector lots of room to reject this even though you're not passing through or over. What I'd do, if the ceiling light has a metal box I'd just use metal cable. If not I'd find a different fixture or else risk it with NM and worst case you need to re-do a short run in a closet. It's not crystal clear so if you're not being inspected you can't get a definitive answer here.
    – jay613
    Feb 15, 2023 at 13:47

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