Unusual 3-way wiring for Linear WD500Z and WT00Z?

Hi, I am running into some wiring problems as I try to map out a 3-way z-wave light switch in my living room, using a Linear WD500Z Wall Dimmer Switch and a Linear WT00Z auxiliary switch. I have looked at existing posts and have found very helpful threads on 3-way dimming, particularly @chrisb for the wiring diagram, and this post here, but my existing wiring setup has me really confused. Apologies in advance if I include too much/too basic information!

This is where I am so far:

Junction Box #1
Is a multi-gang box that houses 3 total switches on the same circuit, with a total of 6 separate lines of Romex going into/out of the box. The old switch I’m replacing is a simple on/off toggle switch. I’ve disconnected and capped four wires from the old switch: 2 black, one red, one ground. After throwing the breaker back on, my non-contact voltage meter gets a live reading on one of the black wires AND the red wire. The other black wire (which was connected to the black screw on the old switch), does not get a reading. There is a bundle of white wires capped in the back of the box, but the old switch was not wired to this bundle. Hoping this is my neutral bundle, to power the Linear.

Junction Box #2 (This is where it gets weird to me)
Is a single gang box with one toggle/dimmer switch, with only a single romex cable going into the box. Since there is only one romex in the box, there are only the usual 4 wires here: red, white, black, and ground. The white wire was connected to the Common screw terminal; the red and black wires were connected to the remaining two screws. After capping each wire, with the breaker on I get a reading from the black, the white, AND the red wire. All of the other regular 3-way setups I’ve seen online have TWO romex going into/out a single junction box. And I don’t understand how all three of the wires are live.

1). In Box #1, how do I use my multimeter to determine which wire is the Line, Load, and Neutral wire for the WD500Z-1? Both the capped red and one of the black wires are live, according to my non-contact sensor.

2.) How can all three wires be live in Box #2? What can I do to troubleshoot this to determine which is my neutral and which is my true hot wire to connect with the Master?

3.) Does it matter which Linear switch I use in which box? My gut tells me to use the master WD500Z in Box #1, and the auxiliary WT00Z in Box #2.

4.) Does anything about my current wiring setup indicate that I simply won’t be able to install these Linear switches? I don’t want to burn another day if it just won’t work without additional wiring, but I don’t know enough to make that call just by looking at what wires I currently have.

Thank you for any help you can give! Happy to provide additional clarification. This community has been a tremendously helpful learning tool as I get up to speed.

1 Like

Hi Edwin, #1 all the white wires capped in the back but do you also see a black bundle as well? Since you have 3 different light circuits I would imagine they all share the same source. Look for a black bundle with a piggyback black wire. without removing all the wires. you can check for source with the breaker on and the switch pulling away from the box. I think the reason you have power on both red and black is because the power source is still tying in the circuit and you didn’t cap the wiring on box #2 or fault reading with your meter.

#2 assuming you cap all the wires on box #1 and #2 and not isolating the power source wire yet will give you fault reading with a sensitive non contact meter. or you didn’t cap the wiring on box #1.

#3 the location of the switch is depending on where is power source is. WD500z usually installed where there is power source.

#4 It will depends on the finding of #1 and #2 above.

I have seen some pretty crazy wiring and without looking at the actual wires I can only guess. can you access the light fixture box? I would go there if I still couldn’t find the black bundle or power source as stated above. the electrician could run the power to each light fixture circuit or hide the black line hot somewhere. It’s more accurate to get a cheap multi meter for troubleshooting. A non contact is more for a quick check of live wire on a bundle but not individual wire dual to leakage. If you don’t mind. can you take a couple of picture of the boxes?

not sure what happened but I see half my post with huge font. sorry about that.

Thanks for the response, Ray. I attached some photos that might help.

Photos A and B (below) are of Junction Box #1. Photo A shows the wiring on the old switch. The black and red wires on the top of the switch are the ones that get a live reading when I have them capped. Photo B shows the wiring after I capped all the wires on the old switch. I circled the 4 wires from the old switch in Orange, and I circled the three bundles that I can see in Green. You can see one bundle is the white wires. The green-circled bundle at the bottom of the picture has mostly black wires but there is ONE white wire also. The green-circled bundle on the top right is all black bundled wires. The two live wires from the old switch (orange-cicled at the top of Photo B) run directly to a Romex; they’re not bundled. The black wire that is orange-circled in the center of Photo B is not live, but it is bundled into the black bundle on the top-right.

Photos C and D are of Junction #2.

So to answer your first question, yes I see one bundle in Junction Box #1 that has all black wires, and one bundle that has all black and ONE white wire.

I have capped all the wires from the old switch in Junction Box #1 AND capped all the wires from the old switch in Junction Box #2.

I do have a multimeter with me, but am not sure how I would use it to determine my Line and Load wires in Junction Box #1, or why all the wires in Box #2 are apparently live. Do you have any suggestions?

Can you clarify what you mean by this

not isolating the power source wire yet will give you fault reading with a sensitive non contact meter. or you didn’t cap the wiring on box

I did cap all the wires from the two old switches in both boxes.

Thanks again, very much appreciated!

Photo A (Junction Box #1)

Photo B (Junction Box #1)

Photo C (Junction Box #2)

Photo D (Junction Box #2)

since you have a multi meter. Here’s a way to check for source. At box #1 put one of the meter lead on white. and the other on common of your switch. You should get 110V regardless of the switch position. check red ( traveler ) by one lead on White and the other lead on red. You will get 110v when the switch is on or off but not both. Same thing with the second black (traveler). 110v on or off but not both.

with everything still connected. Box #2 with one lead on common (white in your case) is usually load. you can verify this by having one lead on common and the other lead on red or black. Whichever gives you 110v. Now go to box #1 and hit the switch to a different position and you will see the red and black on box #2 change state. Doing the same thing with the light bulb removed will give you 0v between common and red or black. that will confirm your white on box #2 is load. I think you have this setup below except they switch the white and black on your #2 box. http://www.easy-do-it-yourself-home-improvements.com/images/Large-3-way-switch-3.jpg
The thing with a non-contact meter is when you have a live wire close enough to a dead wire not connected at both end. Depending on how sensitive the meter is. You will hear it beeps.
Hope that will help.

I’ll have to wire up the switches before I give this a shot. Thanks for that link to the wiring diagram, it does look similar to the setup I have.

Another has suggested this diagram, which seems to be a closer match to my wiring.

That drawing will work only if the load is at box #1. I haven’t given you a z-wave diagram just so you will understand the circuit a little better and have more confident later also not to toast a z-wave switch. Too many people get the load and line wire wrong.

Success! Here’s how I did my wiring, in case anyone else stumbles across this thread. I did not have to use a multimeter for this. I included photos of the final wiring.

As a test, in Junction #1 I unbundled the White wire that was in the Black wire bundle (bottom left of Photo B). All three of the wires in Junction #2 went dead. So I figured that White wire must be how Junction #2 was getting it’s hot, because the other two wires in that Romex cable (the Red and the Black) previously went to the original switch, not to any power source. The key was to get a Neutral going to Junction #2, so the auxiliary switch could work. More on that under the Junction #2 description below.

In Junction Box #1, for the master WD500Z
–Connected the ground to the ground capped wire
–Connected the White wire from WD500Z with the bundled neutral White wires in the back of the box
–Connected the Black wire from WD500Z with the bundled Black wires (from the bottom left of Photo B); This bundle was my Line bundle
–By process of elimination, I found the Load wire to connect with my Blue wire on the WD500Z. Of the three remaining wires that I had unhooked from the original switch, 2 of them (the Red and the Black at the top of Photo B) went directly to Junction #2, so I knew they couldn’t be Load. The only remaining wire, the Black one in the middle of Photo B, must be load. So I connected with Blue.

In Junction #2, for the remote/auxiliary WT00Z
–The remaining wires in Junction #1 were the White, Red, and Black that were all going in the same Romex directly to Junction #2. I tied the White in with the White neutral bundle. This is how I got a Neutral to go over to Junction #2.
–I tied the Black wire into the Black line bundle in Junction #1. I relied on the wiring diagram posted above for this.
–I capped the Red wire in both Junction #1 and #2. No traveler is needed because the remote switch communicates wirelessly with the master.
–In Junction #2, I now had a White neutral, a Black line wire, and a capped Red wire.
–Simply wired the remote switch as normal, black to black, white to white, green to ground.

With power on, both Z-wave switches had the green power light on. The master switch could control the lights, on/off/dim, etc. The remote switch could not, because I haven’t associated it with the master yet. I’m about to do that, using my Vera lite.

Thanks again to the comments from @Navat604!

Awesome you got it working. Glad to hear.

So once you get it all wired properly, how do you control the master with the 3-way switch? I have WD500’s that work great and two WT00Z’s that have power, I want the WT00Z’s to control a WD500Z each… I have no idea how to do this with SmartThings and the directions are a little lacking.


(First post but I’ve been using the forums quite a bit!