3 Way dimming

Hey guys/gals,

I’m a week into the smartthings stuff and enjoying it so far. I was hoping you could answer this one for me.

I’ve got a set of hall lights on a 3 way switch. (One upstairs, the other down). I’d like to dim these, but do I have to buy 2 separate dimmable wall switches or can I buy one dimmable and then use another Z-wave light switch. I assume z-wave switches have to be on both of the switches?

(I’m just going to buy the GE ones at lowes)


I don’t know how the Iris three-way works. But I have used the GE/Jasco three-way dimmers with out issue.

GE/Jasco 3-way switch

WARNING: This GE/Jasco 3-way will NOT work with CFLs or LED lights.

Supposedly they work…I’m just wondering to I need dimmable on each side? Main / Aux or can I have one dimmable, and the aux just be a standard 3 way?

You need to get a 3-way dimmer set. Two standalone dimmer modules won’t work on a 3-way wire circuit.

K, thanks.

What about non dimming…

For example:

My porch lights. One switch in garage, one in front hall. Do I only need to buy one 3 way switch, and then leave the other side the standard light switch? I assume I need both a primary and auxillary BOTH zwave/smartthings etc.

If you are NOT dimming and the Z-wave module is just acting as a on/off 3-way switch then it will work with an existing 3-way auxiliary switch. Make sure the Z-Wave switch is a 3-way type. It has to have that extra connection terminal on it.

Thank you Steve, I’ll give it a whirl.

The GE / Iris switches at Lowe’s work well and come in a package for 3 way. Around 45 for both switches. And I can confirm that they work well with SmartThings

Thanks guys, now it’s a matter of figuring out how to wire the thing. I heard the instructions aren’t that good.

3-way setups in Z-wave land are a bit of a different animal than normal three way setups.

A “standard” 3 way has wire coming form the breaker box (LINE) to the first switch. Then you get two traveler wires running from the first switch to the second switch. Then from the second switch you get one wire (LOAD) running to the light fixture. Finally from the light back to the breaker box (neutral). Usually looks something like this:

Note that the color of the wires may be different. These are the colors I usually had, but there’s no certainty that yours will be the same.

Now, in a z-wave setup, regardless of whether you are doing dimming or just on/off, you need a z-wave master switch. This will be connected from from the breaker box (line) to the light (load). The regular electricity does NOT flow through the second switch in a three-way setup. Instead the second switch (call in Aux Switch in Z-wave speak) is connected to the master switch by a traveler wire and when you press the aux switch a slight bit of power flow through the line telling the master that the aux is being pressed and to do something about it.

In most situations you can use one of the traveler wires to act as the load wire. In the second switch box you’ll bypass the switch and connect this traveler directly to the load line. Then use the other traveler to tie back to the primary/master switch. Like so:

The other important thing to note here is that the AUX switch in a z-wave setup will ALWAYS require a neutral. The Master may or may not. Usually it does, but there are some (GE/Jasco 45612, for example) that do not.

Depending on where you have neutrals or don’t have neutral, sometimes it’s better to have the primary switch second and the Aux first. This can be done with the same sort of wire swapping:

So, with any three-way in z-wave land you NEED to use z-wave aux switch. Aux switches typically are the same for dimming and for non-dimming setups. They are interchangeable usually.

Sorry for the long post… but one more important thing I need to say: This is all generally speaking. There are quite often exceptions to the rules in terms of how wiring was setup or your home or how z-wave switches work. I’ve typically used GE/Jasco, Evolve, and Intermatic. Other brands may be a little different. Please follow whatever instructions come with your switches and consult an electrician if you are unsure of anything. Okay, CYA disclaimer out of the way… have fun!


Great work @chrisb. Do you mind if I use this to explain 3-way switches with my friends?

The GE/Jasco 45613 Z-Wave 3-way dimmer manual (this is the unit I’ve used) is online at:
45613 Z-Wave 3-way Dimmer Manual

It has a section on installation wiring if anyone in interested on what the manufacturer recommends.

Feel free to use it Ed… (Not that I could really stop you anyway if I didn’t want you to! :slight_smile: )

Here’s the tactic I’m having a run at.
One aeon dimmer/or switch module, works 3, 4 or n way.
Does require momentary action switches and a relay.

I found this bad boy for the relay:
120vac SSR

I did read somewhere that the aeon switch (and also the dimmer) were supposed to allow 120vac as a trigger input. Yea, well I toasted a dimmer trying that, hence the relay…

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@chrisb Your information helped a friend this weekend. So thank you very much.

Good! I’m glad I was able to help him/her.

I do enjoy the community here that does it darnest to help others when possible. None of this stupid: “I’ll google it for you” crap… Just everyone sharing what they know with others whenever they can.

@chrisb I have installed several single zwave switches (on/off/dim) no problem but am having a hell
of a time doing a 3 way. My basement stairs has a 3 way, top of stairs and bottom and controls 2 lights, top and bottom of stairs. I have neutral in both and I’m able to get power to the master (the blue led lights up). The switches do not work - looking at your diagram, am I understanding that you’ll nut together the traveler to the aux load? I’m so confused with this! I also have a 5-way controlling 2 lights - any idea how to do this?

Thanks so much!!

Okay, if the master LED is lighting up, then you’ve definitely got power to the switch and the neutral hooked up.

What wire do you have hooked up to the LOAD spot on the master?

It’s a black wire - in the master I have 2 blacks, a red and a neutral (and ground) - I just got the light on for a second without changing the second switch - light went on but shorted ( I just wanted to make sure the led lit before I moved on to the aux). In the aux box I only have one black, red and neutral (and ground). So I have a red as the traveler out from master into aux, neutral in both and single black capped in box. I’m not sure if the short ruined the master, still getting blue led.

Thank you by the way!