When the house was built, 3 radon pipes were installed between the basement and the attic. They are 6" PVC plastic are completely within the walls of the home except for their ends. Only one of them is used by the radon sub-slab system.

I need to get get some 120 volt electrical wiring between my attic and basement. Can I legally repurpose one of the radon pipes as an electrical conduit? I'm located in New Hampshire, United States. I'm not sure what the electrical code would say about doing so.

If I can do so, do I need to use a flexible electrical conduit within the radon pipe, or can I just run the Romex through the radon pipe with no additional shielding?

  • 2
    Are you sure about that? Could be they act as intakes for an active Radon system, or they could all be passive vents.
    – isherwood
    Commented May 5, 2021 at 14:31
  • Yes, very sure. The ends of the unused pipes are currently capped. There are three pots underneath the slab for the radon but when the system was installed they pipe them all to the same vent, so the other two vent pipes are unused. Commented May 5, 2021 at 16:29

2 Answers 2


It depends. The pipe is not listed as a wire way or conduit so it would not be allowed for individual conductors you know that by your question.

If you limited the number of cables using MC for example it could be allowed. However more than 6 current carrying conductors may be flagged since it is basically just a hole not a listed gutter.

Would I do it as a professional? Yes even with NMB if I cut the pipe so it is completely enclosed in the wall.

Code allows wires run in walls with the finish or covering and doesn't require stapling. This is even safer for NM, or MC wire types than just in the wall but since it is not a wireway we have to limit the number of conductors and use cables that can be run in the walls, then limit the number so the inspector won’t call out bundling.

Fire block may be required to plug the openings since this bypasses all blocking.

  • But wouldn't a fire block be a good idea regardless of whether cables are run thru these pipes? Commented May 5, 2021 at 17:16
  • @carl witthoft We don’t always fire block but I mention it may be required because it is a good idea.
    – Ed Beal
    Commented May 6, 2021 at 13:51

Here's the problem. Per the NEC you can not use any chase or conduit for wiring unless it is listed for electrical use and labeled accordingly. In most areas I know of, the NEC is adapted as code therefore the law. So in the first part of your question the answer would be no.

As far as using flexible electrical conduit in the radon conduit. I don't know of any code reason you could not do it except the conduit would have to be at least plenum rated and you might have a problem strapping or securing the conduit properly inside the radon pipe. You're also getting into crossover codes about what is allowed in a radon pipe. Because of these reasons I really wouldn't recommend you using it at all.

Hope this helps.

  • 1
    I read it as the radon tube was not used. What is the difference in pulling MC or nmb in a wall of an existing building? I agreey with no individual conductors it’s not a wireway. Limit the number of ccc and bundling can’t be flagged. Put in some fire block foam or putty if there is a concern about the unused pipe being a path for fire and it should be good.
    – Ed Beal
    Commented May 5, 2021 at 14:58
  • @EdBeal - As I said. I don't know any code reason you could not do it. Commented May 5, 2021 at 21:00

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