I need to install a permanent wiring from a receptacle on the ceiling of finished garage to outside of garage (for motion-sensor flood light). The wire will not be below 9 feet level.

Do I need to use conduit in the first place?

Assuming yes - I'm planning to extend an outlet, replace with GFCI and then run the wire through PVC conduit attached to the ceiling. Second question - can I run wire directly through the wall from PVC conduit? Or do I need to connect it to a junction box (and then from junction box to run wire through the wall)?

  • Is the ceiling a finished surface? – ThreePhaseEel Jan 20 at 12:37
  • Yes, the ceiling is a finished surface. – ZakiMa Jan 20 at 19:36

Generally speaking, wires within reach need to be protected. Above 9 feet is out of reach, doesn't need to be protected, so conduit not required. If you use conduit then you can use separate wires. If you don't use conduit then you use cable - normally non-metallic cable, aka Romex.

However, you do not normally need GFCI on permanently wired lighting (except above a tub or shower or certain other places). In fact, if you want to GFCI-protect a ceiling receptacle, you can't install a GFCI/receptacle in that location because the GFCI has to be easily accessible. At the same time, if the receptacle is only used with out-of-reach stuff (e.g., ceiling lighting or fan) then you don't need GFCI anyway, though local code may vary.

As far as conduit through the wall, I am pretty sure that is fine, but one of the experts will speak up if there is a problem. In fact, I suspect it is the opposite - running loose wires (as opposed to cable) outside conduit, even just to go through a wall, is not allowed.

  • Thank you for pointing a code about GFCI accessibility (glad that I mentioned it)! I don't think it is required in my case to have GFCI, I thought about it as it would not harm. – ZakiMa Jan 20 at 8:36
  • So, it sounds that in my case I can have extension box on top of my current ceiling outlet, plug a cable into it, let it go along the ceiling and directly into the wall and plug it into plastic round box on the outside. – ZakiMa Jan 20 at 8:38
  • Not exactly. If you use conduit and put conduit through the wall to the outside directly into the box then you're in great shape. If, on the other hand, you use cable, then going through the wall to the outside (not simply running inside the wall, which is normal and protected) may raise an issue regarding outside == water. I'm really not sure on that - I'm not a pro and the only things of that sort that I have done have been straight replacements, so the cables already in place (and hopefully done right the first time). – manassehkatz-Moving 2 Codidact Jan 20 at 15:08
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    Thank you! The external part is a separate topic. So far I'm planning to use a plastic box for dump/wet locations (sealable), a cable graded for wet outdoor conditions and a cable connector which provides watertight connection. And then seal everything (except the bottom) with a silicone. – ZakiMa Jan 20 at 19:34
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    Going back to internal part of this project - sounds that running a cable on a ceiling without a conduit is fine because it is out of reach. – ZakiMa Jan 20 at 19:36

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