A quick guide to running power through framing for lights

I went through this exact process a couple of years ago when I was setting up a workshop in my backyard. It was a bit of a pain to get the right spot, but totally doable. I found my existing top plate was 2.5 inches thick, which is thicker than I expected for just drywall backing. I ended up using a heavy-duty auger bit instead of a standard hole saw beacuse I wanted to make sure the hole stayed perfectly round while I was drilling through the wood. I was nervous about messing up the structure, but I had to proceed. I just made sure I marked the entry point on the inside face first so I could maintain a perfectly vertical cut. My main concern, which wasn't really discussed, was making sure the cut wasn't hitting any existing cable runs that might allready be packed inside the wall. Before I started the drilling, I traced the path of the old utility lines visible in the wall to make sure my new penetration was completely seprate. I definately left about two inches of slack in the new cable inside the hole. That extra room felt necessery to prevent the insulation from rubbing against the wood fibers over time. It's always better to be over-cautious with the framing.

I did the same job in my own garage last spring, pulling power for four LED shop lights off a nearby outlet circuit. One thing I'd add is what happens after the cable goes up through that plate. Mine popped out into the attic and it needed to be stapled down within about a foot of where it came through, otherwise it just flops around where anyone storing boxes up there can step on it or snag it. Also worth checking what else is on the circuit before you tap into it. I traced mine back and it turned out to be shared with half the kitchen, so I ended up running a fresh line from the panel instead. Night and day difference having a dedicated lighting circuit.

Total beginner here so apologies if this is obvious, but I did something similar last month when adding a light in my detached shed. Mine went through the wall header instead of a top plate, and I got stuck on wether the cable needed a metal plate over the hole so a future nail or screw doesn't hit it. My brother-in-law who does handyman work said to check whatever the local code office says, which honestly felt like overkill for one light but I called anyway and they were surprisingly helpful. Is that something you've looked into for your garage, or does this kind of job usually not need any paperwork?

Did plenty of these over the years and I'll say a flex bit and a glow rod changed everything. Back in the day we'd just use a long auger from above and hope the bit came out where you wanted, wich worked maybe half the time. Now I drill a small pilot hole up in the attic right next to the plate, drop a fish tape down the wall cavity, and pull the cable up from below. Saves all the guessing and you barely enlarge the hole at all. If your attic access is decent it beats working blind any day.