First off, Speedy Petey , don't laugh at me...you helped me a lot over "there", maybe you can do the same now, you'll probably want to reach through the screen and smack me on the head.....
I recently pulled a 3 wire feed to a sub panel on a detached building at my house because I have always done it this way (twice before), I drove a ground rod at the building and bonded the grounds/neutrals in the sub panel to the neutral bar.( have no other metallic paths) I used #6 AL wire for this feed and plan to feed it with a 50A breaker in my main panel. I will have a 46A demand in this building if everything runs at one time. Can I use one of my hot wires as a ground wire by tracing and labeling it with green tape on both ends, isolating it with the other grounds from the neutral bar in the sub panel and only feed one side of the sub panel with the other hot since I only need 46A and will have a 50A breaker(change to single pole). Is there any reason this is unsafe to do? I ask because I now have learned that my township is under the 08'NEC. I will not have an inspection on this, but I've just really confused myself over what I should do...leave it/ change it. I'm starting to feel as stupid as I sound...I need a new brain,or a brain at all
Im in process of doing almost the same thing, only Im going with 100amp. All the info I have gotten from research is that the feed from the panel to the detached dwelling must be a 4 wire feed. 2 hot 1 neutral and one equipment gnd. With the gnd and neutral being separated at the building.
As well sub panel can only have 6 breakers if no main in said building.
Im not electrician by any means Ive just been hovering over these sites for a few weeks.