I am trying to wire 3 way switch - Cooper Wiring Devices S106P-W-K 3WAY SLIDE DIMMER

Hi Carl

I'm an electrician and can help you with this problem. It sounds like you've got a "3 way" circuit - that is; you control the light with 2 or more switches (assuming all three wires were not connected to each other - but had individual connections to three screws or three wires on the dimmer).

If this is the case, you need to replace the dimmer with a 3 way switch. A 3 way switch has 4 terminals - one is a green hex-headed screw for ground, 2 others are golden or brass screws for the black wires and fianlly a black or significantly darker screw that is for your red hot wire.

A 3 way switch has no ON or OFF markings on the handle. If the replacement switch has such markings, or has only 3 screws (ground and two golden or brass colored screws) it is likely a single pole switch; and will not work with the other switch(es) to control the light. You will need to obtain a 3 way switch before continuing and wire it as described above.

If you have further questions, leave them in a comment & I'll give you more help. Good luck!

A 3-way light switch needs 3 wires for both switches to work correctly. If there is only 2 wires on the switch, its not a 3-way. Only two black wires on the switch means it can be wired either way. The power and light leads are inter changeable. If you really need a 3-way switch, be sure it is labeled as that on the box and look for 3 connections on the switch its self. Else, try a switch rated for a higher amperage.

You have 3 cables entering the box.
Each cable has black and white and ground wire.
You have a single pole switch.
The switch has 2 brass-colored screws and 1 green-colored screw.

1) One thing is certain: all the ground wires connect together and then connect to green screw on switch.

2) After that, we are guessing without more information.
Add a comment.

3) What does the switch control?

4) If the switch controls a hallway light, and there is another switch for the same light: then you have wrong switch. You need 3-way switch. Buy 3-way switch and re-post question at fixya.

5) If switch controls a bath fan-light combo, repost question at fixya.

6) If the switch controls a regular light, and no other switch is involved: then the following information might work. Or you need to do testing and re-post another question at fixya.

-White wires probably connect together and are covered with a wire nut.

-Then two black wires connect to one brass screw and 1 black wire connects to other brass screw.

-But which black wire?

-Only one of the black wires has power from circuit breaker. That is hot wire.
-Hot wire connects to 1st brass screw on switch. Either screw.

-And then connect one of the other black wires to 2nd brass screw. Turn on power and see if light turns on.
-Try other black wire same way.
-The black wire(s) that turn on lights on should be left connected to 2nd brass screw.
-If one black wire did not turn on lights, then that wire probably connects to 1st brass screw along with hot wire.

Decora 3-way and 4-way switches do not wire differently than toggle-type switches.
Instructions below are tedious but will accurately guide you to solution.

Let's break down the problem starting with 3-ways.

1) Start with 3-way switches:
Old 3-way switch has 2 brass screws and 1 dark screw
New decora has same color screws.
Wire that went to dark screw on old device must attach to dark screw on decora device.
Other two wires can attach to either brass screw.
Wires that attach to brass screws are travelers ... these wires travel to the 4-way switch.
So there are 2 traveler wires at each 3-way switch.

2) Let's test if 3-way switches are wired correctly by taking 4-way switch out of equation.
We will resolve problem with 4-way switch after 3-ways are correct.

There are 4 wires at the 4-way switch.
These are the 2 traveler wires that arrive from each 3-way switch.

At the 4-way switch, 2 wires arrive in one cable, and 2 wires arrive from another cable.
To say it differently, there are 2 wires from cable1 and 2 wires from cable2.
Connect 1 wire from cable1 to 1 wire from cable2 with a wire nut
Now connect the 2nd wire from cable1 to 2nd wire from cable2 with another wire nut.
So now the traveler wires are connected, and the 4 way switch is out of equation.
Turn on power, and click 3-way switches to see if both switches turn lights on-off in all positions.

Do your 3-way switches work correctly?

3) If 3-ways are not correct, then you have wrong wire connected to dark screw.
First thing to check is if you can identify traveler wire colors by looking at wires at 4-way switch.
Remember, traveler wires at 4-way switch go back to 3-way switch and connect to brass screws on 3-way switch.

4) If you cannot tell traveler wires by looking at 4-way switch, then you can try different combinations until both 3-way switches work.
Or you can test: disconnect wires from one of the 3-way switches. Separate 3 wires for testing. Move other 3-way switch to down position. Turn on power. Test each wire to bare ground wire. Mark wire that lights up. Now move other 3-way to up position. Test each wire to bare ground wire. If same wire lights up each test, then that wire goes to dark screw. If different wire lights up, then mark that wire. The two marked wires are travelers, and they connect to brass screws. Other wire connects to dark screw. Repeat identical test for other 3-way switch.

At this point your 3-way switches will work, if light bubs are not burned out.

5) Last step, the 4 way switch.
Remember from step above, that 2 wires arrive in cable1: These 2 wires connect on one side of 4-way switch. The other 2 wires that arrive in cable2 connect of other side of 4-way switch.

Add a comment if you need more help.

Three way switch diagram: Three-way switch has 3 screws



Before replacing old 3-way switch, mark the wire connected to dark-colored screw
Connect that wire to dark-colored screw on new switch.

If you are confused which wire goes to dark-colored screw
Mark the 2 black wires and the red wire.
You are not going to do anything with the white wire.
Connect blacks and red to any screw, turn on power, and try BOTH switches
Keep trying until correct combination is discovered
Both switches must work in all possible up-down positions before wiring is correct
Incorrect wiring will not blow circuit breaker, the circuit just doesn't work until wires are right.

Four way switch is added to 3-way circuit

If I understand correctly, you are trying to identify wires inside a 3-way switch box?

Common wire is the wire that connects to dark-colored screw. Before taking wires off 3-way switch, it is customary to mark the common wire.

If you already have switch out and can't remember which wire went to dark colored screw I suggest you put old switch back in place and try the wires on different screws until both 3-way switches work correctly. Don't worry, circuit simply doesn't work if wires are placed on wrong screw.

You may also be trying to identify Hot and Neutral wires.

Hot is usually black, Neutral is usually white.

Here's how to test. Separate wires. Turn on power. Use ordinary tester. Tape tester leads to wood sticks so hands are away from power. Test each wire to bare ground wire. Tester lights up on Hot wire. Next, test Hot wire to each wire (except ground). Tester lights up on Neutral.

you have the circuit mis-wired, the wire on the identified terminal( black screw or black wire on dimmer switch) is incorrect. Turn off power and swap one wire at a time to find the correct combination. The mistake could be at either switch so if the first does not help try the other.

nevermind

Wiring a bathroom combination vent, heater, light 3 way switch means more wires. In brief, you need to run two cables - one a two wire and one a three wire from the switch to the fan.

Incoming power will have white black and ground.

The two wire cable for the switch to the fan will have wht, blk, and ground.

The three wire will have red, blk, wht, and grnd.

The switch will likely have 2 blacks and a red coming from it, with two blacks and a red on one side, and a single black on the other.

The fan should have a red, blue, green, black, and white.

On the fan end: Group all green/copper grounds together and use a wire nut to fasten them together. Tape the nut to the wires.
There will be five white wires coming through. For ease of handling, using wire nuts, connect two on one nut and three on the other.
connect the blue to a blck. Connect one red to one black, and the other red to the other black.

The switch will have one red going into the 3 wire cable, a black going to the 3 wire cable, and a black form incoming power to the side opposite the 3 wires, and a blck going to the two wire cable.

There. Confused?

The answer to your question depends on the manufacturer and type of 3 way dimmer you are using... generally you can use a 3 way switch as a single pole switch, but whether or not this holds true with the dimmer you are using depends. Let me know what you are trying to acomplish and model numbers mfgs of what you have and I'll try and help