Wiring – How to fish low voltage wire from finished attic dormer through heavy framing

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I want to reroute this wifi camera’s 5V power cable (currently going through the window) through the wall.

My idea is to drill a small hole in the wall where the purple circle is, route the wire down the wall as shown and then into an unfinished crawl space (red outlined areas). There is a specific problem I’m asking about, and I’m open to other ideas. I cannot get into the dormer soffit, it’s finished with no access.

The issue is that the framing is all very heavy. The green lines indicate actual 4×4 beams and the horizontal one between the dormer and the crawl space is even heavier. I can get into the crawl space beneath it, and drill up into the wall as shown by the yellow arrow. But the bottom plate of the dormer is very wide at that point. It extends about an inch out of the dormer into the roof space below, and about two inches into the dormer where it forms a ledge you can see in one of the pictures. My fear is that drilling up from underneath as shown by the yellow arrow I might end up going through the roof or into the inside ledge.

I can make small holes in the interior wall to help fish the wire through. I'd like to avoid opening a huge hole in the interior wall, from where I can easily drill down into the crawl space but then refinishing is more work than the entire project would be otherwise.

Note, aside from the question itself, my intention is to install an outlet in the crawl space, run my own low voltage wire from there to the outside, and splice it to the camera connector outside and to the wall wart inside.

Photos:

  1. outside, showing location of camera, desired cable route (purple), location of unfinished spaces under roof (red), locations of heavy framing (green) and location markers 1 and 2.
  2. inside ledge at bottom of dormer showing where oversized bottom plate protrudes into attic.
  3. Same corner of dormer showing framing in crawl space.

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Best Answer

It's probably reasonable to assume the wall board has equal thickness above the ledge and below the ledge. Then you can measure the depth of the ledge at the yellow arrow, which is front-face to front-face of the wall board. Bring that measurement into the crawl space and measure off the back side of the lower wall -- this tells you where the back side of the upper wall is at. Add another inch and you've got a position that is comfortably inside the upper part of the wall.

If you'll still prefer to drill down rather than up, consider a long drill bit (sometimes called a bellhanger drill bit). You could use it to pierce the interior drywall and continue on through the lower framing. Yet another approach is to remove the right-hand piece of window casing. There should be a gap between the window and the rough opening. You can drill down in that space, again with the bellhanger bit, and afterward reinstall or replace the wood casing instead of repairing a hole in the wall.