My breaker box is on the interior side of my garage wall. I want to add another line for some outlets in the garage. How would I go about doing this?

 

You would install a 20 amp breaker and run #12 NM-b or conduit with individual wires to each receptacle.

If the walls are not enclosed or you are going to run the wiring on the surface of finished walls you would use conduit and single conductor THN or THWN wires; black, white, green.

If you are going to install the wiring inside finished walls you can use 12-2 NM-b (Romex).

You would need either a GFCI breaker or use a GFCI receptacle at the first outlet and feed the remaining receptacles from the load side of the GFCI receptacle. Regular non-GFCI type receptacles would be used after the GFCI and labeled GFCI Protected.

 

Okay, that sounds easy enough, BUT... How do I attach the conduit to the breaker box? The wall is a finished/insulated wall where the breaker box is.

 

Is the breaker box flush with the wall or surface mounted?

 

The box is flush with the wall.

 

Carefully remove some of the drywall above the panel to get access; there are obviously lots of wires in that cavity so don't cut deep. If you don't break the piece of drywall you remove, you can put it right back and mud it or just leave it attached with a few screws as a future access panel. Otherwise, just fabricate an access panel out of wood or drywall and use that to patch it up.