3-Way Smart Switch Question

Just a quick integration question. As I slowly replace the switches in my home with smart ones, I have been dodging my 3-ways due to complexity and cost. Well I am ready to tackle the issue. I just want to make sure I am understanding what all I need to get to make it work.

So let’s say I have a 3-way switch. On one side I install this:

GE Smart Dimmer, Z-Wave, In-Wall, 12724, Works with Amazon Alexa

What do I put on the other side of the 3-way?

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GE add-on on switch 12723.

And both function the same manually, correct? So it doesn’t matter which is on which end?

In a typical 3 way wiring setup, you could set it up so the master could be at either end. A typical wiring setup will have line voltage (coming from the breaker) come into one switch box, while the load wiring (to the light fixture) will come out of the other switch box. Then there are two travelers that run between the two. The master switch needs both the line and load wiring in the same box, so you would use one of the two travelers to “jump” either line or load to the switch box where you want the master. Then the other traveler would be used as the signal wire for the master and add-on to talk to each other. There are several ways to wire a 3 way setup though, so you need to make sure you know what you have and which wires do what. If your wiring is different than the scenario I described, you may need to wire things in differently. There’s no one-size-fits-all way to set it up. Regardless though, 3 way smart switch wiring is different than standard 3 way wiring, so you can’t just replace dumb switches with smart switches, hook wires up the same, and expect it to work.

Before you are going to tackle your 3 ways. Look at this site for your wiring configuration. Figure out what you have first, take pictures for future reference and daw out on a piece of paper on how you are going to reconfigure your smart switches to your wiring.

If you have options 5, 6,7,8 then The GE switches won’t work due to no neutral wire at the switch boxes. With options 1-4 and 9. You should be able to place the master switch at any location you want with the use of an add on at the opposite location.


Having replaced several 2-ways already and since my home is new construction (1 yr old), I’ve already discovered that I have a neutral wire to the switch boxes.


Sounds like you should be good to go, as mentioned be sure to take a good picture ahead of time in case it doesn’t work the way you expect. I’ve replaced 3 sets of the 3-ways in my house and 2 of them went super simple and straight forward. The 3rd one though was a PITA because it was not wired conventionally (possibly not to code either). I had numerous wires tied together both hot and commons in the same twist. After sorting that mess out I still could not get the basic light function working. Turns out the wires in the fixture had the hot common swapped on one end and used the red traveler feeding the other leg. Needless to say I had to rewire the whole multigang box, the light box and the traveler switch at the end of the line.

I recommend getting the main switch working first in the box with the feed first and then hook up the traveler wire to the mix. You don’t want to hook up the red traveler and have the wiring not behave as you expected because the red wire is running 120v and fry’s both your switches. The ‘dummy’ switch really on has 2 wires hooked up (excluding the ground) it has a neutral feed and the traveler that only connects between the main load switch and the dummy switch.

yup, work the same. Only difference is the master has the blue led and the add-on doesn’t.