3 way switch - adding in a switch

jamiedolan · 10-23-2008, 12:18 AM

I have a ceiling light, power comes in on a piece of 14-2. A piece of 14-2 leaves the box and goes to 2 switches - two 3 way switches.

I know that I need to use a 4 way switch when adding a
a third switch to a 3 way setup. what I am confused about is where the connection to the other switches has to be made.

I suspect that I have to run all the way back to one of the 3 way switches, and that there is no way to add the new switch in from the fixture box. Does it matter which of the 2 way switches I run to?

3/4 way switches still confuse me a bit, I've seen many of them, and read about them, but I get a little confused on some of the wiring plans for 3/4 ways.

Thanks
Jamie

InPhase277 · 10-23-2008, 01:57 AM

Quote:

Originally Posted by jamiedolan

I have a ceiling light, power comes in on a piece of 14-2. A piece of 14-2 leaves the box and goes to 2 switches - two 3 way switches.

I know that I need to use a 4 way switch when adding a
a third switch to a 3 way setup. what I am confused about is where the connection to the other switches has to be made.

I suspect that I have to run all the way back to one of the 3 way switches, and that there is no way to add the new switch in from the fixture box. Does it matter which of the 2 way switches I run to?

3/4 way switches still confuse me a bit, I've seen many of them, and read about them, but I get a little confused on some of the wiring plans for 3/4 ways.

Thanks
Jamie

You need to study some diagrams of how 3-way and 4-way switches work, and that may help with your confusion. I have some I'll post. A 4-way has to be inserted in between the 3-ways, which means that, not including the ground, four conductors land on the switch. You could take a piece of 14-2-2 to one of the 3-ways, if there is enough volume in the box.

So, now, you have two 3-ways. In the box with the new 14-2-2, remove the travelers from the switch. Connect these to two of the wires in the 14-2-2. Connect the other two wires back to the 3-way. At the 4-way connect the four wires to the switch in the proper manner depending on the switch brand.

joed · 10-23-2008, 11:32 AM

You can connect from either of the 3 ways switches. Run an new cable from the existing switch to your new switch. The existing switch will be the 4 way and the 3 way will move to the new location. This will work with ANY exisitng 3 way 4 way setup no matter how it is wired as long as you work from one of the the 3 ways.

Remove the existing 3 way making note of which wire is on the COMMON terminal. Connect that wire to the wire of the same colour in your new cable. If there are any other wires in the switch box, leave them alone.
Connect the remaining two wires to one set of terminals on the 4 way.
Connect the two remaining new wires to the other set of terminals on the 4 way.
At the new location connect the old 3 way exactly the same as it was in the old location.

jamiedolan · 10-23-2008, 11:59 AM

Quote:

Originally Posted by joed

You can connect from either of the 3 ways switches. Run an new cable from the existing switch to your new switch. The existing switch will be the 4 way and the 3 way will move to the new location. This will work with ANY exisitng 3 way 4 way setup no matter how it is wired as long as you work from one of the the 3 ways.

Remove the existing 3 way making note of which wire is on the COMMON terminal. Connect that wire to the wire of the same colour in your new cable. If there are any other wires in the switch box, leave them alone.
Connect the remaining two wires to one set of terminals on the 4 way.
Connect the two remaining new wires to the other set of terminals on the 4 way.
At the new location connect the old 3 way exactly the same as it was in the old location.

Thanks guys for the diagrams and information. I reviewed a number of other 3/4 way diagrams online and although it is still a bit confusing in application, but I do think I understand it now.

So when you wire 2 / or 3 way switches, you use 14-2-2 between all the switches? and then you can run regular 14-2 to the fixture and to your power source.

Now with 14-2-2 wire does that have 2 black wires and 1 white to be used as a common neutral? If the color of the wires the only thing different between 14-2-2 and 14-3?

Thanks
Jamie

InPhase277 · 10-23-2008, 12:35 PM

Quote:

Originally Posted by jamiedolan

Thanks guys for the diagrams and information. I reviewed a number of other 3/4 way diagrams online and although it is still a bit confusing in application, but I do think I understand it now.

So when you wire 2 / or 3 way switches, you use 14-2-2 between all the switches? and then you can run regular 14-2 to the fixture and to your power source.

Now with 14-2-2 wire does that have 2 black wires and 1 white to be used as a common neutral? If the color of the wires the only thing different between 14-2-2 and 14-3?

Thanks
Jamie

I'm sorry for the confusion. Joed is also correct, and provides a simpler or cheaper solution. I personally had a situation where I had to use the 12-2-2 setup. But 14-2-2 has 5 wires total: black, red, white, white-red, and ground. It is intended to be used for 2 circuits with separate neutrals. Electricians have come up with creative uses for it. But use 14-3, it is cheaper.

I had a commercial service call where I added a 4-way, and everything was in junction boxes. That's where the 12-2-2 was handy.