The NEC allows NM, but some local codes (Chicago being a notorious example) require all wiring to be in conduit.

Not to hijack, but I have similar question. We want to install exterior GFCIs on our garage (forgot during build, we have one on back of house and 2 on porch but they're too far for charging battery on tractor, etc.). Have 20A circuit for interior garage receptacles and 1 dedicated for freezer.

Electrician did not use conduit - ran all the 12/2 (and 14/2 for lights) up in trusses, then down through holes along studs where (plastic) outlets are located. I want to pull off one outlet in back of garage, would be easy to take out a couple of staples, pull wire up, drill new hole and run it down a few feet over for new exterior box. Then to save wire I was hoping to run either straight through a couple of studs (as is done in interior house wiring) or *down*, put the holes low in studs, and then up a couple of feet to new box. If I ran straight across I would put in conduit. If I ran down to sill plate, would it need to be in conduit? Or, do I have to run *up* and over like all the other wiring in garage?

Walls are just studded out, no insulation or drywall (except shared wall with house). We may finish them at some point.

" If I ran straight across I would put in conduit. If I ran down to sill plate, would it need to be in conduit? Or, do I have to run *up* and over like all the other wiring in garage?"

Ask your AHJ.

It all comes down to the interpretation of 'subject to physical damage' in the NEC.

There are some AHJs that make a big deal of exposed NM that is in reach from people, tools, stored material, etc. while other accept that NM on the side of a stud or running in bored holes through studs (stay 1.25 in from the faces) is acceptable.

Running higher on the wall does put the cable in a location less likely to be damaged, but it is stil the AHJs call.

Well, our electrician thought running along the side of studs was fine. Frankly, I don't think the AHJ even looked at it. He left, we've got a new inspector in town, I don't know if I want him to look at it b/c I don't know what he's going to think of original work.

I figured running 2-2.5ft off the floor might be subject to damage (esp. since DH likes to store tools in back of garage, most hanging on hooks on outside of studs but he stuck some strapping across and sticks long-handled tools in there - I would have to get him to change that to put new outlet in the location I want near the back corner - just found hacksaws hanging on a nail right near drip loop for floodlight!). Wasn't sure about sill plate or toward the back of the cavity (put a "plate", even if it's just plywood or a 2x6, over it so broom handle doesn't sit on wire?).