I would like to be able to add a fluorescent light fixture (T8's) and outlet to my indoor garage. I plan on running 1/2 inch conduit with 12 gauge romex wires. I have an existing 60 Watt light fixture circuit (tied into a light switch) I want to use the power from. However, I need a little help with the wiring. I went ahead and made up a rough draft drawing of my plan to wire this. EDIT Or... there is an existing outlet I can also use power from as well. If this would be easier? *Edit#2 Disregard my ground wires question. The only question I have is if this wire diagram that I have drawn is up to code and is safe to wire it like this?
Your drawing looks fine, as it is. However, the "up to code" section is tricky and more involved:
Your current existing wiring had to be up to code as it was at the time the house was built, and we assume it was. However, if you alter the circuit (add outlets, lights, etc.), the whole circuit has to be up to code as it is now. So all receptacles have to be GFCI protected, a certain minimum height from the floor, etc., etc.
Without knowing more about your current wiring, and without knowing your local bylaws, it's impossible to tell if this change you're planning will be up to code or not.
There are also other things to consider, like maximum fill for a electrical box (if you're adding more wires to your light switch box, you might be in violation of the electrical code because of that).