Adding a Subpanel

Last fall our home got updated to 200 amp service. My garage is attached to house by a breezeway. My garage has electricity in it, but i think its all original and just about everything is on one circuit. I would like to install a subpanel in the garage. I am planning on running a dehumidifier, an extra refrigerator, a garage door opener and eventually a air compressor (not a big one just for home use) and a couple extra outlets. My garage has sheetrock on the walls and I do not wish to remove the sheetrock to access the old outlets and wiring. I am planning on running on the outside of the sheetrock using conduit. My question is what kind of subpanel would I need (rated for)? What gauge wire 10, 8, 6 would be sufficient? My main panel is located about 50 to 75 feet away from the garage. Any help would be appreciated.

 

Get a 100 Amp main lug panel and run a 4-wire #6 AWG romex cable to the new panel. Do not "bond" the neutral bar (white wires) in the subpanel with the green screw or bonding strap and do install a ground bar for your equipment grounding conductors (bare copper). In the main panel, install your two phase conductors on a 50A double pole breaker and your neutral and ground on the neutral bar. I am assuming you have an "attic" above the breezeway to allow the use of romex.

In the garage you will need to run wiremold or conduit for surface mounting your receptacles.

 

Do you think the 100amp panel is overkill? When you say do not bond the neutral with the green screw or bonding strap, do you mean keep the neutral (white) and ground separate from one another. Also, the ground bar you are referring to is that the ground rod I have on my main panel that is burried in the ground.
This 100amp main lug panel does it have its own main disconnect breaker?

 

100A panel is standard. You can get a small one that will only hold 8 to 12 circuit breakers. It is rated for UP TO 100A but you will be feeding it with a smaller circuit.

Yes, grounds and neutrals must be kept separate in your subpanel. A "ground bar" is a bar that mounts directly to the steel of the subpanel and is where you terminate your equipment grounding conductors (bare conductor in romex). It must be purchased separately (same brand as your subpanel).

You don't need a main disconnect for your subpanel, unless you want one for some reason. The 50 amp breaker in your main box will serve to disconnect power from your subpanel.