Replacing my 3 prong dryer outlet but there is a blk, red, wht, and a bare wire in the box. I know where the colored ones go on the outlet but what do I do with the bare one? I didn't remove the old one so I don't know how the old 3 prong outlet was wired with these wires. Thanks.
The bare is the ground wire and it should go to the ground connection in the J box. If this is a new dryer, you need a 4 pin outlet and cord so the ground is brought to the dryer. Older units ground the neutral in the dryer with a jumper that must be removed when changing to the 4 pin configuration.
I said it to you before, you basically have an illegal circuit, at least for a clothes dryer. There is no way to legally or safely use that for a typical electric dryer. You need to have it re-wired so that you have separate neutral and ground conductors, and with a four prong receptacle. A properly installed (complaint to pre 1996 NEC) 3 wire dryer or range receptacle will have a white insulated neutral or be an SEC with a bare shield as neutral. A white/black/bare NM-B was never permitted for such a circuit. Wiring neutral to ground in a receptacle simply is not permitted. Just don't ask why. You have your answer do not ask again. Nobody should be telling you to do something unsafe and illegal.
4 wires means you need a matching 4 wire receptacle.* Black and red go to L1 L2, the white to N and the bare wire goes to the green screw. If the wall box is metal the ground needs to attach there as well. Then replace the cord on the dryer to match that configuration. Most dryers are 220/240 volt 30 amps. * Now you are in compliance with current National Electric Code standards and your insurance company will thank you. (well not really, but it sounds good)
