I am running 6/3 NM from my panel to an outdoor generator power inlet box, and installing an interlock switch on the panel. I am looking for the correct way to run this wire through the exterior sheathing and into the box. The only knockout on the inside of the box is on the bottom and the box does not sit exactly flush with the siding when lined up with the knockout. The distance through the wall is approx 2.75" inside to outside (sheathing, wood shingles, foam, vinyl shingle). I'm thinking I need to use conduit or fittings to somehow to make a continuous connection from the garage to the inside of the box, but I'm not sure and would like the correct answer here. Thanks in advance!