Ok, I'll try to explain as best as I can.

Basically I have a space above my electrical box that leads into the unfinished section of the basement, with a bunch of electrical wire running through.

As it happens I periodically want to run a new cable through this space, and it's a pain in the butt every time to get the glow rod through.

Question: Can I put some flexible conduit up there to provide an easy raceway for future Romex runs? It wouldn't terminate in a box, it would just be there to be an easy pathway for rods or tape in the future and fully insulated Romex would go through it.

Above the electrical box, one side of glow rod Where the glow rod comes out on the other side

  • 4
    What is a "glow rod" ?
    – Alaska Man
    Commented Jun 14, 2020 at 23:24
  • 1
    How long of a sleeve are you looking at putting in here? Commented Jun 15, 2020 at 1:05
  • 2
    @AlaskaMan It's a fluorescent fiberglass rod for fishing wires inside a wall
    – Machavity
    Commented Jun 15, 2020 at 12:48

3 Answers 3


Yes, this is a good idea, but a few details.

  • No more than four cables per conduit, unless you're willing to upsize ALL the cables to the next larger size. That is 310.15(B)(3)(a).

  • The conduit needs to be fairly large, because the cables are oval. Each oval cable is treated like a single wire of the wide dimension (because they twist). They can't fill the conduit more than 30% (for two) or 40% (for three or more). 1-1/4" conduit is probably a safe choice, though 1-1/2" will be easier to pull. (pulling stiff Romex is a bugbear). *This is not a Code requirement per se, but it'll surely be a practical limit given NM-B tends to have kinks, and kinks snag like crazy in conduit.

  • Flex is a bad idea. I know it seems easy to install, but the flex will fight you every inch of the way. The energy you are using to push or pull the cable will instead bend the conduit sideways. Believe me, this is very frustrating, especially when pushing, and pushing is (otherwise) easier since you only have to watch one end. With a non-flexible conduit secured at both ends, that's an non-issue.

  • Assemble the conduit first, then fish the wires through it.

  • AFAIK conduit fill requirements do not apply when the conduit is being used for protecting a cable, as illogical as that might be.
    – mfarver
    Commented Jun 15, 2020 at 17:28
  • @mfarver I wouldn't doubt it, however reality conspires to almost moot the issue. First thermal derate does apply so you're still at 4. Second the stuff kinks, and thus, snags. Commented Jun 15, 2020 at 22:48
  • @Harper-ReinstateMonica -- the OP can get around the thermal derate issue by keeping the sleeve <24" in length, though Commented Jun 15, 2020 at 23:12

Yes, you can run NM/Romex cable through conduit. This is generally used to protect the cable in exposed areas. As long as the conduit is designed for electrical work, it should be fine. Sorry, you can't use Spa hose (but I've seen it tried)

They sell special bell ends for PVC conduit that ensure that the cable does not get cut or damaged by the end of the conduit. It would be wise to use these if you can locate them, or some other fitting that will protect the NM/romex from getting damaged. PVC Bell End


stick a rope though there that's reaches more than twice the distance, tie each end to an anchor point.

when you need to run a cable pull the rope's slack to you side then tie the cable to the middle of the rope, then go to the other side and pull the rope until you get to the cable untie the cable and leave the rope for next time.

  • Tie? A small length of electrical tape is more than good enough - if it does actually slip, then nothing is lost, and it is much less likely to snag than a knot.
    – MikeB
    Commented Jun 15, 2020 at 13:37
  • tape leaves a sticky residue, but yeah that would work too.
    – Jasen
    Commented Jun 15, 2020 at 13:45
  • 4
    Use gaffer tape, then. A gaffer is a lighting electrician on theatrical productions, so it's not, "not electrical tape". It is designed to come off cleanly. Commented Jun 15, 2020 at 13:55
  • 1
    Have you ever tried to remove gaffer tape after a long while, or after it was exposed to heat? Coming off "cleanly" is not how I'd describe that.
    – KlaymenDK
    Commented Jun 16, 2020 at 11:37

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