Hello,

I've just purchased a 3-way dimmer (Leviton 6633-L) for our living room, but I'm not 100% on this and I'm hoping someone can help?

The 3-way dimmer has the following wires (and has the slider for dimming plus and on/off switch):
- red
- red (has an "insulation" label attached and instructions say this is there for instances when second red is not required)
- black
- green (ground)

One wall box contains the following wires:
- white
- red
- black (common)
- bare copper wire (ground)
(white/red/black currently connected to an on/off light switch)

The other wall box contains the following wires:
- white
- white
- red
- black (common)
- bare copper wire (ground)
(white/red/black currently connected to an on/off light switch, second white connected to another white leaving the box and is not connected to the on/off switch)

Is it possible to hook up the dimmer to either of these boxes?
If so, which wires go to which?

I assume black to black (common), red to red, green to bare copper wire (ground) — but what about the second red?

Any help would be appreciated!

Regards,
Kristin.

 

You have identified one wire in each box as "common". How did you come to that conclusion?

If you are correct about which wire is the common, then it connects to the black wire on the dimmer. The two travelers (the other two non-ground wires currently connected to the old switch) should be connected to the two red wires on the dimmer (one to each). All other connections in the box (if any) should be left alone.

And yes, you can replace either switch with the same algorithm. Leave the other switch alone.

 

Well, the two (black) wires I identified as "common" were connected to the black screws (bottom, left or right depending on how you're looking at it) on the current switches, which should indicate common. This should typically suggest the common, no? I suppose someone could have put the screws in wrong at some point though, so maybe I shouldn't assume? How would I go about actually testing to be sure?

Thanks!
Kristin.

 

First let me say that top, bottom, left and right are meaningless when trying to describe which wires connect where. It depends on the brand and how the device was installed.

On a 3 way switch the "common" terminal will be a different color than the other 2 screws. Typically this is a dark color and the other 2 are brass. I am ignoring the green ground screw for simplicity.

 

Yea, that's how I came to the conclusion on what was actually the common — on the two previous switches (of which I'll be replacing one with the new dimmer), both had a single black screw and all other screws were brass. So, I had assumed that this meant, from everything I've read, that the black wires, attached to the black screws, were common.

Thanks to everyone for the help!!!!

 

If the old switches worked properly, then the common was on the correct screw and you can rely on it.

 

Thanks again — I'll post the results!
k.

 

Just a quick update —*the install was simple, quick and now works great! Thanks again!
Kristin.