Adding 60 AMP breaker to existing box...
I recently built a studio for my wife behind our house. I put a GE 8/16 125 AMP subpanel breaker box in the studio. I was going to install a 60 AMP breaker into the breaker box in the house and run 2-2-2-4 aluminum in PVC conduit underneath the house, through the block foundation and in a trench out to the studio. The problem I have run into is that I can't figure out where to tie the ground and common wire into the the house breaker box. I had a 70 AMP circuit run to an exterior sub-panel box for a greenhouse a couple of years ago. The electrician used the main lug on the ground bar for the ground on that circuit. I also noticed he did not run a common to the sub-panel.
I guess my question is, do I need to just run a ground and two hots to the panel in the studio? Is there some type of modification I need to do to the panel in the studio to tie the ground and common bars together? Also, is there some type of adapter to put on the ground bar in the main house panel to put the #4 ground wire into?