The place I am currently living in (a duplex) had a 220 volt outlet for a large window air conditioner.

The circuit was removed from the panel when the place was upgraded to central air.

I would like to convert the outlet from 220 single receptacle to 110 duplex receptacle. The wires are run through BX and consist of 12 ga Black and Red, no White wire and no ground. I am assuming that the BX is acting as a ground.

Can I run the Black wire into a new breaker (15 amp as that is what I have for both the breaker and receptacle) and then run the red wire into the neutral bar?

Also, I need to lengthen the wires to fit into an open spot so I could splce a white wire to the red if that would make things better. (I would twist the wires and use a wire nut/tape on the splce)

Thanks for your help!