I am planning to run both coaxial and cat5e cables from my basement to my (finished) attic, along the outside of the house. I'm trying to figure out the best practice.

If it were a single cable, I think I would just drill a hole through the wall, feed the cable through (taking care to leave a 3" turning radius on the cable run), protect the cable from the aluminum siding with a "mushroom" bushing, and seal it up with silicone.

But I'm reluctant to do the same thing for another cable right next to it. I thought maybe a slightly larger hole with a slightly larger bushing could accommodate both cables, but I don't know if such bushings exist.

Another option I've seen is to drill a 1" hole, run PVC conduit through the wall, and attach an LB box on the outside. Sounds good, but what seals the opening on the inlet side where I'll be inserting the cables? Or does this commit me to using conduit for the whole run?

1 Answer 1


I would consider putting this type of box at the soffit where the outside wall meets the roof and drill at an angle into the attic space assuming your attic is accessible. Then fish the interior wall.

You could also use PVC conduit which is paintable and strap it good as it will warp. outdoor weather rated enclosure

  • 1
    I should have said that I'm trying to wire a room in the attic between knee walls that is finished. And the cavity of the wall I'm trying to penetrate is filled with fiberglass insulation. Although I could penetrate into the crawl space behind the knee walls and go through the knee walls. Commented Jul 30, 2015 at 14:21
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    I did almost this exact thing, and it's not terrible. I had the benefit of old, unused telephone wiring running throughout the house without any staples. I was able to use this like string to pull through those old runs. Commented Jul 30, 2015 at 17:22

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