I'll be honest I didn't read your entire post, but the solution is simple. It sounds like you only have three conductors and a ground in the box you replaced. In this case the electrician sent the hot back to that switch box through one of the conductors in that single wire. Most likely the white or neutral wire. Try putting the white wire onto the common screw and see if that fixes it. Make sure you turn off the breaker first and test all of the conductors for power before sticking your hands all over them. A sure fire method to find out which conductor has been dedicated as a hot or common wire, would be to dismantle the first switch and see which wires are jointed together with the hots in that box. (I.e. if you see two or three black wires wire nutted together with a white wire, then that's the designated hot.) Your original electrician most likely pulled the conductor to the light from the wrong side of the circuit. To answer your question if it is dangerous....I wouldn't say it's "safe" to leave it how it is, but I have been on service calls a thousand times where the customer claims their three ways operated incorrectly for years without incident. If it's an older dwelling, the hots and joints may be made up in the box the light hangs from, in this case the solution will be the same. The only difference is you wont be able to see what wire is designated to send the hot back to the right side of the circuit by looking in the other switch box.. I would advise you to have an electrician rewire the switches eventually. Those neutrals are designated as neutrals to balance the load on the circuit. Designating one as a conductor is common practice, but imo is lazy and incorrect.

Are the light you are trying to control now controlled by a single pole switch? Are you replacing that single pole with a 3 way and adding a 3way at another location? If yes to both, then connect the incoming hot to the common (black) screw of the new 3way at the existing box, connect the black of the 14/3 to the black going to the light, and connect the red and white of the 14/3 to the other two screws of the 3way switch. Leave the whites already there alone. At the new location, connect the black to the common (black) screw and the red and white to the other two screws.

OH man!!! I knew that 12/2 traveler seemed odd. I should have gone with my first instinct!! That is how I originally had it roughed in then found that posting and changed it all today..all for it not to work!!! ugh!! I have wired 3 ways before but I'm getting confused with the fan/light feature. Also, I think what is confusing me is that the way I originally had it, and the way you are stating, box 1 with the feed is "in between" the fixture and the other box. Does that make sense? I know that might not be accurate but that is how my brain sees it. Meaning, box 2 has the 2 runs of 14/3 coming over to box 1 which has the feed and then the run to the light. So let me try to figure this out and correct me again if I am wrong. The rough should be: Box 1: 14 or 12/2 feed; 2 runs of 14/3 to box 2 and a run of 14/3 to the fixture. Then from there I am reading your instructions but having difficulty picturing it..not sure if it's fatigue and late but..is there any way you could diagram it for me? maybe in an email or something....i'm dying over here to finish this up. thanks, brian

Hi! Maybe what I was trying to describe is not called a switch loop. Maybe I should have given an example of what I am talking about. Let's take my brother's "den + 2 bedrooms" circuit. The power comes from the panel to the ceiling fixture box via a 14/2 loomex. From there another 14/2 loomex goes to feed the outlets in the den, and another 14/2 loomex goes to bedroom #1. Also, a 14/3 loomex (bare ground + white + black + red) goes to the switch for the den light. At the fixture box, the whites are wire nutted together, and the bare grounds as well, which are also attached to the box and has a pigtail for the fixture. The blacks are wire-nutted together and the red wire (from the switch) is alone. The hot wire from the chandelier is connected to the red wire and of course the neutral from the chandelier goes to the whites marretted together. The hot black wires are just standing there. Then at the switch (which is mounted on the wall separating the den from bedroom #2), there is the 14/3 from the light fixture box and another 14/2 loomex that goes to bedroom #2. In the den switch box, all grounds are wire-nutted together and attached to the box, all whites (neutrals) are wire-nutted together and the two blacks are wire-nutted together with a pigtail that gets attached to the switch. The other leg of the switch is attached to the red wire that goes to the chandelier. I hope this description makes it clear. Please note that I live in Montreal Canada and I have seen this wiring technique at my aunt's house (built 1964) and also at other friend's houses where I helped with wiring or installing light fixtures. Can someone please tell me if it is still allowed, and if I can use more than one fixture wired this way per branch circuit? Thanks a lot.