Please excuse me if this has been asked before, I searched previous questions but didn't find anything similar...

I have my computer in our garage because of less noise, heat, dust, etc... also it's pretty cool all year, so I'm not worried about heat issues in the garage.

Is it against code (Bozeman, Montana) to run cables through an interior wall to a garage? How can I do this correctly?

Is there something I could install with/around the cables that would prevent gasses from coming in, etc?

Right now the cables are running inside the wall and in our crawlspace.

A rough layout of my new wiring idea

  • 3
    A local electrician finally replied to my question: "Keep penetration above 18" in the garage (below 18” is considered hazardous due to the potential of gasoline/oil on the floor) and then you need to maintain a 2 hour fire rating on the actual penetration. The easiest way to do this is to use a chase such as EMT conduit or schedule 40 PVC conduit through the wall and then seal it with drywall plaster on the garage and interior wall. You would need to use a fire stop caulk or foam sealant which are readily available." Is this a standard reply or does something sound sketchy?
    – Eric
    Nov 3, 2014 at 18:56
  • 2
    @Eric Sounds okay to me. Just make sure you use the fire stop caulk. You want to maintain the walls fire resistance, and prevent any dangerous fumes.
    – Tester101
    Nov 3, 2014 at 19:59

2 Answers 2


It depends what you mean by "cables". As long as it is a data cord (not power) and the opening is fire sealed, it is fine. What I do is use a cutoff saw (hack saw is fine) to cut a length of PVC pipe. Use a hole saw to cut through the drywall. Then, caulk the PVC pipe to the dry wall. It makes a perfectly clean tunnel through the wall. You can feed data cables through this tunnel. There is no code violation for doing this as long as the cables are data cables and you fill the tunnel afterwards with fire proof sealant.

Note that you cannot have any "wall penetration" between a garage and a bedroom, but it appears from your diagram that the adjacent room is not a bedroom.

  • See International Residential Code 2012 R302.5.3, and National Electrical Code 2014 400.8(2) & (6).
    – Tester101
    Nov 3, 2014 at 16:54
  • Thank you Tester101 for the code references. I would not be running any power cables through this opening, only HDMI, DisplayPort & USB.
    – Eric
    Nov 3, 2014 at 18:48

If you're within the city limits (or the donut) there are some NEC rules that will apply and you should probably consult a certified electrician as the NEC is vast and fairly dense. If you're just "in the area" of Bozeman but not within its jurisdiction, you're subject to rural code... which is no code at all. In this case use good common sense, spray foam any holes you punch down in to the crawl space to stop moisture from percolating up into the conditioned space, and if at all possible terminate your ends in junction boxes with an appropriate face plate so it looks professional and you should be fine. Also...cats drool, grizz rule.

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