To make my garage more usable as a workshop, I'm planning to add a subpanel which can feed a number of additional outlets. 60 amps would be plenty for my current needs, but I'd like to go with 100 so I have the option to add an electric heater, or possibly a welder.
My garage is attached and I've found a path for the feeders that is about 40' long. What I've found so far leads me to believe I need #3 copper THHN wires, plus a #8 ground. Does that sound right?
I've also gleaned that these need to be enclosed in conduit, but I'm having a harder time nailing down the specifics for that. I'm thinking plastic conduit would be easiest for me to work with, but do I need a specific type? Also, it will be routed out through the rim joist into the exterior garage wall built with 2x4s, so max hole size is 1.4".