Burying MC cable in wall?
The 4 exterior walls of my house are solid brick. 2 layers of regular brick, then a layer of cinder block, then the plaster wall material applied directly to the cinder block. Because of the difficulty of installing them I imagine, the builder (in 1938) only put two receptacles on the outer walls, and both are in the living rooms.
I needed more, obviously, so I dug out a few square holes for new outlet boxes with my hammer drill. I also dug small trenches (about 1") in the plaster/brick going down from the box holes, past the floor and into the basement. I attached the boxes in the holes with tapcons, and ran MC cable through the trenches and into a junction box directly below in the basement, where it meets up with regular 12/2 romex and heads to the service panel. I then filled in the trenches with drywall mud, completely engulfing the MC cable, sanded it down, reattached the trim, and painted.
I did all this a few months ago but never got around to actually hooking the lines up to the service panel. I was going to finish this project up (finally!) tomorrow and I thought about something that I don't think I ever thought about before...would the MC cable have any sort of issue with heating up because it is completely buried in the drywall mud? Now this is 12/2 cable for a 15 amp circuit, so it won't be overloaded by any means. But I just didn't know if it would be an issue.
I ran a similar line for a low voltage receptacle and I actually buried a piece of conduit in the wall so that I could slip the wires through it and possibly add lines if I wanted to upgrade something later. Now I'm thinking it might have been better to simply run romex through a piece of buried EMT, because then it would have more space to breathe. What do you all think?
Thanks in advance!