I'm planning on running a 6/3 feeder cable from my main panel to the garage for a small 50A subpanel and am unsure of how to plumb the new cable to the main panel. All of the knockouts are on the bottom of the box, and I want to run some conduit from the panel to the attic along the exterior wall. Rather than adding a couple of elbows in order to run the conduit from the attic to the knockout on the bottom of the box, can I drill a new hole in the side of the panel, near the top for the 1" conduit? I imagine I would need to use an LB here and at the attic entrance?
Here's what I am thinking: