Easy 3 way switch problem

I'm not an electrician by any means and I don't know the technical jargon, but I have wired household stuff up before, so I wouldn't consider myself a newbie to electrical wiring. This, however, is new to me:

I have a bathroom w/1 light and 2 switches. (Both switches are supposed to control the same light) I was going to make both switches 3-way switches, but here's the problem. One box is straightforward - bare copper ground, white common and separate red and black power wires. As of now, there is no switch there as I've capped the red wire and twisted the white and black together to make a full circuit. Everything works just fine right now.

The other box is confusing. Right now, it's wired to run off a single pole (?? only 3 places to hook wires) switch and it's wired as such: red wire to the green screw (ground) and 2 black wires to the only other 2 screws/ports. (Power?) Inside the box, there are 2 conduits and out of those 2 conduits there are 2 twisted bundles of 3 wires: 2 black and a white wire twisted together and 3 white wires twisted together. There's also a bare copper ground in there.

My question is this: I need to wire a 3 way switch in there. Obviously, I have a red, black and copper ground, but I need to replace one of the black wires w/a white (common, traveler, etc) wire. Which bundle does this wire need to come from? 2 black/1 white bundle or 3 white bundle?

Thanks in advance!!

 

Straightford but there is no color code for 3-ways so you can't assume white is common. Even if it is on the common terminal since the circuit doesn't work you can't just assume.So either black or white is common.We don't concern or self with grounds when making a circuit work so do you mean two screws (+ ground)?In a conduit system white should never be used as a common or traveler. Are you sure it isn't cable?A red wire is never connected to a ground. You have a mess but first tell us for sure if it is cable or conduit. Pictures made with the wires pulled out but left connected so we get a clear view might help. http://www.doityourself.com/forum/li...rt-images.html

Note you mention bare copper wire so I'm guessing cable. If so what you wrote makes some sense. WE need the pictures though. We also need to know the wiring at the light.

 

 

The pictures show a single pole standard switch. The red wire connected to the ground screw needs to be immediately removed. It's the red from a three wire cable. It looks like all the pictures are of the same box. It looks like 1)three wire cable and 3) two wire cables. You're going to need to carefully pull the connections out of the box without disturbing them.


This is only part of the story.

 

We need pictures of the other switch box and of the wiring at the light?

Do you have a multimeter, preferably, analog? (A non contact tester won't work.