I am wanting to install a new 100 amp subpanel to an existing 200amp main panel. I went to Home Depot and recently purchased a 100 amp panel that has a 100 main breaker already installed in that box. Is that ok to use as a subpanel? Also what gauge wire should I use to run to the sub? Do I ground the new sub or run the ground back to the main panel?
I appreciate any help you can give me.