If you can get a hot and neutral line into the box then you could have another relay in that box. Trade those switches out to regular switches and have each one trigger a separate relay. Then you could do some software magic to make either switch turn the light on/off. (You’d just make them sync, there are several smartapp/devices that link two things together.)
I have the Enerwave Z-Wave Plus ZWN-RSM1, my 3-way setup is wired like option #3 from the listed diy website. Power comes into one switch, passes through light fixture to other switch. I’d like to wire the relay in at the light fixture since my boxes are shallow. Is there a way to do this?
After reading all these posts I’m still unsure which z-wave relays people have gotten to work with a 3-way switch and how it needs to be wired? Any help would be appreciated as I’ve tried using the MP 11989 with no success.
As long as your wiring is normal, it’s pretty simple to do.
If you draw out your existing wiring to your lights and switches I can take a look and give you some suggestions.
So I’ve been lurking in the community forums for a long time, and have learned so so much from the active contributors. Usually, any issues I’ve had I’ve been able to solve by browsing through the forums. However, I’m currently stumped. Reading through this topic, I can’t quite tell if anyone has successfully wired a Monoprice dual relay in a 3 way light switch.
I have installed several of the single relays and dual relays in basic two-way switches, but when I try and tackle a 3 way switch, I never get 100% success. Usually the best I can do is get it where it works about 80% (won’t turn off the light if both switches are in the up position, won’t turn on if both down, etc…)
I see posts that say it IS possible, depending on particular wiring setups, and not possible in other situations. I’m hoping that I can get clarity on which situation I’m in - I really want this to work. I’m far from an electrician, but here’s a description of my setup, as far as I can tell. Trying to control some hallway lights off the kitchen area. For now lets concentrate on just the first relay (if I can get it working properly I would think the second relay would be the same)
Switch #1 is in a 2 gang box. When I pull it out of the wall, the switch has three connections to it (4 counting the ground wire). I’m fairly confident the top two connections are traveler wires to switch #2 (fwiw, they are black and red). The third connection is at the bottom of the switch, which I believe is a live line, as this gang box has a bundle of black wires pig-tailed together in it. It also has a bundle of white wires (I presume the neutral?) in it.
Switch #2 is in a 4 gang box at the other end of the hall. When I open it up and pull it out, it has a similar setup. Black and red travelers connected at the top, black wire at the bottom. There is no bundle of black wires pig-tailed behind this switch, but there is a small bundle of white. (Well, there is a bundle of black, but it’s at the opposite side of the 4 gang box for the other unrelated switches on a separate circuit).
So based on this, can a Monoprice dual relay be used? If so, how? A clear description would be much, much appreciated. I can provide more detailed descriptions or pics if it helps. Thanks.
Base on your description. You have wiring option #1 on this site. http://www.easy-do-it-yourself-home-improvements.com/3-way-switch-wiring-diagram.html
The in wall micro relay module is not possible for this wiring configuration. Only wiring options 5,6,8 and 9 will work.
I have 5 monoprice relays and 2 of them in 3 ways switches with no issue.
Thanks for the prompt reply. That’s why this community is so great. However, your news is disheartening. Based on my setup, is there any way to jerry-rig it? Or is there a different dual relay that would work? I’ve got several locations I’d like to use a dual relay in a 3 way switch, and I assume most, if not all of my switches, are wired the same (house was a new build 5 years ago).
Again, thanks. 
There is hope but not sure if it’s feasible since you are looking for an affordable solution.
Aeon labs makes dual relay module and I believe they support momentary switch. What this means is that you could swap out your old switches with momentary switches. Bring power over from the box with power source to the box with the load and use your red traveler wire for your momentary switch.
I didn’t do much searching for this so you have to search for the switches, if this relay supports momentary https://www.amazon.com/gp/aw/d/B01DDQS07W/ref=pd_aw_sim_60_2?ie=UTF8&psc=1&refRID=GHEMD45KGJN6PC8DNXP2#immersive-view_1484854379260 and of course is it cost effective.
In couple of areas in my house I have 3-way setup for 2 different lights as shown in the picture below.
Can I use one ZWN-RSM2 relay and control both the lights without fishing additional wires?
I have successfully hooked up ZWN-RSM2 for the case where I had one 2-way swith and a 3-was slave switch(load wire connected to the light). But I could not figure out how to connect the dual relay module for th econfiguration shown in the picture.
Are the line and neutral in both boxes of the diagram on the same circuit? According to the way they are currently wired, they should be. If they are the same circuit, and 3-wire wires are run between the 3-way switches, it is possible (I don’t see a third wire in the diagram but do see a red wire). If they are only two wire wires then you’ll need two single relays or to fish another wire.
So, I’ve been studying probably a few hundred posts all over the forum regarding 3-way micro switch installation to the point that I almost had myself at the point of failure before I even started. Today I rec’d an enerwave zwn-rsm1 plus & installed on a 4 way circuit utilizing the last 3 way switch in the circuit which had the load wire & 2 other switches that shared a hot wire I could cannabalize. It was easy to find the 2 traveler wires as they each carried voltage differently based upon other switch position. Hooked up the relay & works well. The most difficult part was cramming the relay into the 3 gang box. That and finding the right DH so I could have instant status updates from the physical switches.
Can’t wait to nab a few more, especially if they go on sale.
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Just a point to make when buying relays, make sure the load and line are available in the same box. If you have a 3+way and they are in different boxes, relays will not work.
I was just skimming so dont know exactly what the situation is. I have a problem where on my 3-way switch, the relay wont work. on one set of 3 ways, it never recognizes the voltage change from the switches being on or off, the other set of 3 ways, it will fire the relay on and off quickly when the far switch is toggled off. I believe i know why this is happening but i dont have a solution for it. It is possible it could be done with the programming but not sure.
In both of these switches, the 120V hot wire is running with the two traveler wires. When the switches are on, the voltage from the switches to the relay is 120V. When the switches are turned off, the voltage should be 0V, but because the hot and traveler wires are running together, there is an induced voltage of 40V on the off traveler line. There is no current, just an apparent voltage. This voltage is there even with the wire completely undone. So i believe that when the switches are off, the voltage the microswitch sees is 40V not 0v and therefore isnt firing the relay. the one where the switch is going on and off, the 120V to the light is in the same cable as the travler wires, so when the light comes one, that 120v give the travelers a 40v induced voltage which turns the relay switch off which kills the light and then the 120v is gone so the induced voltage goes away and turns the switch on and the process continues.
The only solution i can see is if in the programming it is possible to have the relay switch when it sees a voltage from the switches that is above or below 100v instead of voltage on and voltage off. That way it looks like the switches are off when the travel voltage is less than 100V, thus ignoring the induced voltage.
I don’t think the 40VAC is your problem. This is a common floating voltage when both ends of the wire are opened and running parallel with a live wire and usually not an issue. I would strongly recommend you double check your wiring.
If you still think the 40VAC is the cause then you could wired a low wattage LED line hot to that 40VAC wire and LED neutral wire to neutral. That should have enough draw to bring the voltage down to 0V for testing your theory.
as soon as i ground it through the multimeter, it works fine.
Thanks for checking. I think you are the second or third person with this issue. Possible @joshuairl has similar issue. Strange enough I have at least 8 of this type of relay module without any problem even with 40+ Vac induced. Try contacting the vendor and see if they have a solution.
What device type are you using?
I found a potential solution to this problem. It does appear the green control wire input to the z-wave module has a very high input impedance, and even a little AC voltage induced on the floating open-circuit travelers will either keep it triggered (i.e. you can’t turn it off with the switches), or causes it to rapidly click on and off, as the OP had found. Whenever I tried checking the voltage between the green wire and neutral with a multimeter, that was apparently enough resistance to kill any parasitic/induced voltage and immediately made it all work properly. So I opened up the case and soldered a 1 Meg ohm 1/4 watt resistor between the green and white terminals on the PCB, carefully insulating the resistor’s wire leads to avoid shorts to any other terminals. Put it all back together and now it doesn’t oscillate on and off and both 3-way switches work properly to turn the load on and off. Also the z-wave controls it properly of course.
Another possible (untested) solution might be to use 2 pole change-over switches instead of the typical 3-terminal single pole c/o in order to actually short the unused traveller wire to neutral instead of leaving it floating open-circuit.
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How are your 3-ways working? Still solid?
My 3-way switches have been performing flawlessly. I have the installation of all in-wall 3-way relays throughout the remainder of my house and have no issues.
Obviously the most difficult scenarios were when the line and load were in different gang boxes but that was rectified by fishing another wire (from a nearby wall outlet on the the same circuit) to the load gang box and rewiring the original line gang box by disconnecting the original line (terminated with a wire nut) simply used the original wire between the gang boxes for a typical 3-way switch.
In one instance I actually moved my 3-way stairway light to a different circuit altogether by fishing a new line from an outlet in an adjoining room.