County Response to 100 amp subpanel
If the garage is a seperate building, then you will have to install a grounding electrode system (usually one or two 8' rods).
Why not get a couple of estimates from licenced electricians?
A 'subpanel' within the same structure requires a 4-wire 'feeder'.
This would be hot~hot~nuetral~ground, the neutral will 'float' or be isolated from the subpanel shell and grounds.
The grounds will be made mechanically and electrically to the subpanel shell.
Both the nuetral and the ground in this 4-wire feeder will then terminate in your main panel or main disco under the same termination bar.
hope this helps.......
[This message has been edited by rpxlpx (edited November 19, 2002).]