3-way wiring

I am closing in an attic space for an upstairs bonus room and need some help with the 3 way wiring configuration. The fixtures I have are two ceiling fans (each with light fixtures) and one additional downstairs light fixture.

I have one 3-gang switch box upstairs from which I'd like to control both fans by a single switch and both lights by another switch and the downstairs light by a third switch.

I have a 2-gang switch box downstairs from which I'd like to control the downstairs light by one switch and the upstairs ceiling fan lights (not the fans themselves) by another switch.

Here is my wiring configuration. I've got a 12-2 hot wire going into the 3-gang switch box (Box A). From box A, I have 12-3 going to the first ceiling fan (Fan A), 12-3 going to the downstairs 2-gang box (Box B) and 12-2 going to a smoke detector. From Fan A, I have 12-3 coming in from Box A and 12-3 going to Fan B. At the downstairs 2-gang switch box (Box B), I have 12-3 coming from Box A and 12-2 going to the downstairs light.

Any help with the wiring configuration would be helpful. I have an electrical book I bought but does not give a wiring example for this configuration. I hope it is possible! Thanks in advance!

 

I'm thinking... but a great idea is to draw a map...

really! for configurations like that it can get really confusing, so draw it out and then wire one circuit at a time....

Hope that helps a bit and I will try and come up with some ideas, but Hey..it's Christmas so don't wait for me!


Merry Christmas
Curtis

 

If my understanding is correct there is one 3-wire cable between box A and box B. Controlling the DS lite from 2 locations and controlling the fan-lites from two location requires two 3-wire cables between the boxes. What's needed is illumination on both Up/Down levels when ascending/decending the stairs.I'm inclinded to suggest you run a 2-wire cable from the DS lite to a lite on the "upper-level" so there's illumination on both levels when a switch is operated.Obviously we don't know what is exposed or what is concealed by wall/ceiling finish----Good Luck!!!

 

Thank you. Your description was very clear. In a few words, you gave a clear description of a very complex setup. Not many people can do that well.

Now the bad news: your existing cabling is not quite sufficient. But all you need is one more 12/3 between box A and box B.

I'll be back later with all the connection information. But first, please confirm that you are able to add the extra 12/3.

 

Thank you for your quick responses. Yes, I will be running an extra 12-3 cable from Box A to Box B in order to control both lights from both boxes.

Merry Christmas!

 

Okay, let's go. First, let's label everything:

• P is the 12/2 power cable into box A.
• D is the 12/2 to the smoke detector.
• X is the first 12/3 between box A and box B (for the downstairs light)
• Y is the other 12/3 between box A and box B (3-way switch loop for the fan lights). Remark both ends of Yw with black marker.
• K is the 12/3 from box A to fan A.
• L is the 12/3 between fan A and fan B.
• M is the 12/2 to the downstairs light
• b=black
• w=white
• r=red

At box A (this box must be at least 45 cubic inches):

[list=1][*]Connect Pb to Db to three black pigtails.[*]Connect one black pigtail to the common screw on S1.[*]Connect one black pigtail to the common screw on S2.[*]Connect the last black pigtail to one screw on S3.[*]Connect Pw to Dw to Kw to Xw.[*]Connect Xb and Xr to the two traveler screws on S2.[*]Connect Yr and Yw to the two traveler screw on S1.[*]Connect Kb to the remaining screw on S3.[*]Connect Kr to Yb.[/list=1]At box B (at least 29.25 cubic inches):

[list=1][*]Connect Yb to the common screw on S4.[*]Connect Yr and Yw to the two traveler screws on S4.[*]Connect Mb to the common screw on S5.[*]Connect Xw to Mw.[*]Connect Xb and Xr to the two traveler screws on S5.[/list=1]At fan A:[list=1][*]Connect Kb to Lb to the fan's black (motor hot).[*]Connect Kr to Lr to the fan's blue (or black with a white stripe) wire (fan's light).[*]Connect Kw to Lw to the fan's white.[/list=1]At fan B:[list=1][*]Connect Lb to the fan's black (motor hot).[*]Connect Lr to the fan's blue (or black with a white stripe) wire (fan's light).[*]Connect Lw to the fan's white.[/list=1]At the downstairs light:[list=1][*]Connect Mb to the light's black wire.[*]Connect Mw to the light's white wire.[/list=1]
Of course, interconnect all grounding screws and wires everwhere, using green wire nuts and/or pigtails as needed.

 

John, I wired as you said and all the switches worked as planned. Thank you all for your help. This site has been so helpful in all stages of my project!