I'm installing a new subpanel for the new garage/shop. I decided to run a ground wire this time instead of trying to ground through the conduit. The subpanel has a bus bar for ground, but I'm not sure where to attach the ground wire in the main panel.
In the main panel, there are two neutral bus bars running down each side of the box. There's the two black mains lines comming in the top, looks like 1/0 gauge or something. There's also an equally big 200amp wire comming into the right neutral bus bar. It's black but with white tape to indicate that it's neutral. The two bus bars are bonded together at the bottom with a bar. At the top of the left bus bar, there's a smaller wire comming out and leaving. It's black with no tape. It looks like #4 to me. It's definitly smaller than the mains wires.
Is this smaller wire going to the grounding rod outside (or water pipe or whatever)? Should I attach the green ground wire from the subpanel to this? It's just the neutral, same as the white wire. Should I just attach the green ground wire to the main breaker box metal instead? Where should I attach it?
brian