I have an attached garage, insulated and drywalled. It has a single outlet on the wall, on a GFCI circuit (a few other outlets around the house are on the same circuit). It has the lights and a garage door opener on a separate circuit. I'd like to tap off the GDO circuit for another outlet on the wall.
First question is: Would this circuit arrangement be code-acceptable (county follows 2017 NEC)?
Second question, if the answer to the first is affirmative, is: What's the simplest way to accomplish this?
Ideally, I'd like to run an NM cable from the GDO outlet (above is unoccupied, uninsulated attic space) to a junction box above the wall exterior, then poke a hole in the ceiling drywall for some PVC conduit and run THHN down the face of the wall to an outlet box. Kosher or no?
In an ideal world, I'd drill through the top plate(s) and run the NM down inside the wall, but without knowing where/if there's blocking in the stud bay, I have no way to drill down through any potential blocking with one of those flex augers. Not enough headroom to operate, and also there's insulation in the way of pushing any NM down. Rather not get into a drywall repair here, either.