Hi, I have a 220v cable running underground to my building (75 feet from my house) that runs a construction heater that I don't use or need. It's a simple red cable with one red wire, a black one and a ground. Is there a way to split that off so that it will be 110v?
That cable is going to have 4 conductors: black, white, green (or bare copper) and either red or blue. The black and the red or blue are your two 110 volt phases. Just like 110 wiring, the white is neutral and the green (or bare) is ground.
This is how I did mine with a 50A (formerly a furnace, I think) outlet and an appliance cord:
I used one of the legs to feed a 110V 20A outlet for my table saw and the other feeds the 15A 2-gang outlet above it and a few more down the line.
The 20A outlet also houses the splice that feeds the 15A run, but if I were to do it again I would give myself more room by putting the single 20A outlet in a double box with a single cover plate.
My panel had a 50A double breaker that I replaced with a 15 and a 20. Otherwise, those circuits are still protected at 50A. Breakers are pretty easy to change out - obviously, be sure to kill the main and leave its cover on when you remove the panel cover because those two terminals will still be hot (and unfused) from the meter pan.
I ought to have run BX where the appliance cord is and for all the exposed romex - I used what I had (same with the boxes).
If you are buying materials anyway, you may as well use the right stuff. Because I rent, everything will be pulled when I leave.