[mdenglund]

Hi All,

I am starting one of my two planned electrical projects and I am hoping for assistance on the first. I have a dining room light that is powered by a dimmer switch. I want to add a second switch for the light by my back door. The dimmer is currently wired with:

- A white wire coming in the back of the box and heading out the top (no pigtail connections)
- A black wire coming in the back of the box, pigtailed to another black which goes into the dimmer switch
- Another black wire coming from the dimmer switch, pigtailed to a brown wire going out of the top of the box
- A ground wire attached via screw to the metal box

What is throwing me off is the absence of another wire (I think) for the 3-way switches. Don't I need a traveler or a switch wire that can trace to the light and then to the new switch? Sorry if this is seemingly simple and I am missing something! My prefrence is to understand completely before I climb in the attic to explore and cut a new switch hole in the wall!

Thanks in advance!
Marty

 

[Jim Port]

You are going to need to run a 3 wire cable from switch to the new switch location. You will wire the new switch as a dead end 3 way.

 

[joed]

This is simple once you get a 3 wire cable to the new switch.
I am going to skip ground wires in the description. Connect all of them together and to the switch if it has a ground screw.

Remove the two wires from the existing switch. Leave everything else alone. The wires could be both black or black and white. Might even be black and red. It doesn't matter.
Connect one wire to the common screw of your new three way switch#1.
Connect the other wire to the black wire to your new switch#2 cable.
Connect the red and white wires to the remaining two traveller screws of the new switch#1.

At new switch#2 connect the black to the common screw.
Connect the red and white wires to the remaining two traveller screws of the new switch#2.

Since it sounds like you might have conduit these direction might vary slightly since you are not using a cable but individual wires in pipe. The wire connections will not change just the method of getting the wires between the switches and possibly the colours you use.

 

[mdenglund]

Wonderful - thank you for the detailed explanation!

 

[rjniles]

Based on the OPs description of the wiring, it sounds like it is run in conduit. The Op should verify if conduit is required in his area or if the use of cable is allowed.

 

[mdenglund]

I do not think the current run is in conduit, but I am not certain. The run is up a wall and into the attic from the origional 1955 wiring when the home was built. Is it the lack of ground wire coming in that you are assuming it is run in conduit? How would the wiring of the switch differ if it is not in conduit?

 

[sirsparksalot]

I do not think the current run is in conduit, but I am not certain. The run is up a wall and into the attic from the origional 1955 wiring when the home was built. Is it the lack of ground wire coming in that you are assuming it is run in conduit? How would the wiring of the switch differ if it is not in conduit?

It's the brown wire that makes us think it's in conduit because cable is generally Black, Red, White, and Bare/Green. Having the brown wire suggests it's not cable, but rather, 3 individual wires ran through conduit. Or, at least, I think that's what we think

As joel said, the wiring is the same.

I think I would add that at one of the switches (Sw1), the wire (Black or Red) that goes to the Common terminal needs to be the HOT wire from the breaker (or jbox somewhere). On the other switch, the Common terminal gets the Black or Red wire from the light.

I know I'll hear about it if I'm wrong

 

[hammerlane]

Hi All,

I am starting one of my two planned electrical projects and I am hoping for assistance on the first. I have a dining room light that is powered by a dimmer switch. I want to add a second switch for the light by my back door.

Is the dining room light only controlled by this one dimmer switch? Or is there another switch somewhere that controls the dining room light?

 

[mdenglund]

Is the dining room light only controlled by this one dimmer switch? Or is there another switch somewhere that controls the dining room light?

It is currently only controlled by the one dimmer switch. Also, for clarification, there are only two wires coming into the box, just white and black. There is no ground wire that enters - there is only one off of the switch. I found this odd, as all of our outlets have a ground wire coming into the boxes. It is the brown wire that looks to go to the fixture (out the top of the switch box towards attic).

 

[hammerlane]

It is currently only controlled by the one dimmer switch.

If only controlled by one switch, why is there tak about travelers and 3-way switches?

Is the diagram below similar to what you think you have??

 

[hammerlane]

for clarification, there are only two wires coming into the box, just white and black. It is the brown wire that looks to go to the fixture (out the top of the switch box towards attic).

So are there 2 wires into the dimmer location or 3? You say 2, white and black but then you reference a brown wire.

Decide what it is. Possibly a picture may help.

 

[mdenglund]

So are there 2 wires into the dimmer location or 3? You say 2, white and black but then you reference a brown wire.

Decide what it is. Possibly a picture may help.

Here is a photo - hopfully that will help! Sorry if it is difficult to trace/follow from the pic, but with my description in the first post, i think you should be able to see.

Thank you all for the assistance!

 

[joed]

Looks like conduit to me.
What is your location? Some areas like Chicago REQUIRE all electrical to be in conduit.

 

[mdenglund]

Looks like conduit to me.
What is your location? Some areas like Chicago REQUIRE all electrical to be in conduit.

I am in Minneapolis, MN.