I would like to run some new outlets in my garage. There is currently a subpanel located there, the run will be fairly short. I have a section of armored cable which was left over from work at my office that I'd like to use. I'm thinking of using a setup which I have seen used in other houses, but want to run past you first.
The armored cable has two 10-gauge (white & gray), 4 12-gauge "hots" (various colors), and two 12-gauge grounds. I'd like to use it to run 4 20-amp circuits. Circuits A and B would come off of opposite phases, and share one of the neutrals and one of the grounds. C and D would be run similarly. That way, neither neutral would ever carry more than 20 amps.
I know that I would never exceed rated ampacity for any conductor, but I do not know the NEC well enough to say whether that will meet current code or not. Anybody want to chime in?