Zooz Zen27 3 way wiring. Ugh. no neutral!

I am really start to hate the wiring in my house. I am trying to wire my Zen 27s to the 3 way circuits in the house. I pulled hte first switch in the line out and took a look at what I had…

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It looks like the forum is cropping my pic…


So the wires coming in / out of the box are 12/2 with ground. And I have no clue how this works. there is a load, a line, and a traveller, but no neutral, no gound. How the heck is this working at atll?

The neutral is probably that white wire hanging out by itself. In a ganged box of switches they would all just be bundled in the back of the box. So it looks like you have everything you need. I am not familiar with the Zooz switch but the GE switches I have wired would work I believe.

The white wire attached to the switch is the traveller. My issue is there is no means of having both a traveller and a neutral going between switches…

I am talking about that white on the left with nothing connected. That should be the neutral, I think. Wire color especially in older houses doesn’'t always follow any standard. Sometimes even in a new house.

When I was wiring up a three way switch in my last house I had a switch where they used the bare ground wire as line. It was okay though because they wrapped it with a electrical tape. :roll_eyes:

We are talking about the same thing. That white orphan capped wire is the neutral coming in.

All of the possible wiring diagrams going between switches and the load have a hot feed / line, neutral, and a traveller, That would require 14/3 wire with ground. I have 14/2 with ground. I am missing one wire. The neutral is simply capped, not nutted and connected through…

The good thing, this is a single story home and the run between boxes is relatively short. The bad part is, I can guarantee the wire is stapled to the studs. Fishing through the wall will be anti fun…

What does the wiring in the other box look like? Remember that standard 3-ways actually have 2 ‘travelers’ between them. Normally, 12/3 is used between the boxes to carry both travelers and a hot, but the circuit will work if the 2 wires on the left are line and neutral with line hooked to the common terminal of the switch and the other two wires (wht/blk) going to the other switch. The other switch can then have its common terminal connected to the light fixture. The neutral can then be provided at the light fixture or by a second line/neutral at the other box. Not exactly to code but if it was a homeowner job and all they had on hand was 12/2, it would function.

Contact Zooz support! They are quick to respond and very knowledgeable. I used them to sort out an issue I had wiring a 3-way.

For Zooz Zen27, the smart switch goes in the box with the line wire (the one that is always 120v regardless of how the switches are thrown). The neutral in that box doesn’t have to go thru to anywhere, just connects to the neutral terminal on the switch.

Seeing what’s in the other box will help verify what you’ve got, though.


Yeah, I have to pull the other box apart. 2 different circuits not on the same breaker. Need to ID the second breaker before I go yanking it apart…

It’s possible that the second box is the first in line / hot…

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You should be able to make this work. A dumb 3-way switch will have 3 conductors going between the two switches. But with the smart switches, you are only going to use two of those (assuming Zooz works like Jasco/GE/Honeywell). That leaves a spare wire that you can use to port over neutral from the same circuit to the other box. As for ground, tie into the ground bundle there (after testing it really goes to ground).

I bet when they installed this, they didn’t have a 12/3 Romex, so they used two 12/2.

Zooz Zen26 and Zen27 do not work like most other smart switches in 3-way applications. With these, you use your existing dumb switch on one end (the end without the line/hot), usually with wiring unchanged.

Neutral is only needed on the end where the Zooz switch goes. The dumb switch end uses the travelers just as when there was a dumb switch on the other end.

When in doubt, take pictures, check voltages (non-contact probe!) and contact Zooz support! Wiring it wrong can damage the switch.

Tagging @TheSmartestHouse


Ah, OK. Still, if things test out like I suspect, I bet there are four conductors (2*2) going between the two switch boxes which means you could bring neutral over from the other box. This assumes that switching the Zooz and the SPDT switch location isn’t desirable.

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We’ve never seen 2 14-2 romex cables traveling between switches, but anything is possible. The most probable scenario here is that one of the 14-2 romex cables comes from the panel or lights (so it’s line or load) and the other 14-2 travels between the switches. Technically, the neutrals between the switches should be connected (that’s why the third wire is used in the diagrams) but you could try just using the 2 black and white wires as travelers and the neutral from the romex coming from the breaker (line) to the Zooz switch. We haven’t tried wiring it this way yet but it won’t damage the switch (it may prevent it from fully functioning though). As mentioned by @HalD, it’s best to send the images directly to Zooz support for guidance.

Well, you have to have 3 conductors between two 3-way switches, and since he doesn’t have that, the installer must have run two 12-2s instead. Might have required walking out to the truck to get some 12-3, and it was raining, and he was almost done, so 2 12-2s it was, and then he called it a day.

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THis is the existing switch immediately under the ST hub… It is a 3 way. The regular switches just have a line and load, no neutral. The whtie wire you see here is the traveller, so you have a line, a load, and a traveller, no neutral wire.

You seem to be confirming my suspicion. You have 2 12-2 used to have three conductors to the other switch. That leaves one conductor unused. If you have neutral in the other box on the same circuit then you can pipe that over the unused wire.

I don’t think you quite grasp what the photograph shows in what I am trying to say. There are 2 14/2 with ground cables One coming in 1 going out. The ground wires are wire melted together the black line coming in is wired to the line on the 3 way switch the black line yelling out is wired to the load the white wire coming in is wire nutted off and sitting on its own and the white line going through to the other Box is wired to the traveler lug on the switch.

There is no 4 conductor cable anywhere in this Box it’s all 14/2 with ground. They simply did not use the neutral going between the boxes instead the wire that would usually be the neutral is being used as the traveler.

I don’t think you are reading my posts. Looking back through the thread, I must have said 2 14-2 five or six times (or 12-2 … gauge doesn’t matter for this discussion). I never ever said anything about a single 4-conductor Romex.

In any configuration of 3-way switches, you must have 3-conductors going into each switch box. Since you do not see a 12-3 Romex, then the only way to explain how it has been working is that the installed used 2 12-2s instead.

But hey, we’re here just trying to help explain possible scenarios for the wiring you are seeing. If you’ve got it all figured out, then that’s great.

We’ve definitely seen set-ups where there was line coming into one of the boxes with a 3-way switch through a 14-2 romex and then just a 14-2 romex traveling to the other box where there was another 14-2 coming down from the lights. In that case you just need 2 travelers between the switches, if a 14-3 romex is used, the white wire is usually just bundled with neutrals and not used. So that’s why we suspect only one of the 14-2 is connecting the 2 boxes while the other one is coming down from the light or the breaker. But we can never be sure until we’re actually on sight to verify it.

I think we’re all out of ideas here.

Get on the Zooz support site and open a ticket.

By the way, I noticed you live near where I was until last summer. Lived in the east end of Pearland for 34 years. I’ve escaped to the Texas Hill Country.

For what it’s worth this thread was more of a lament then asking for advice. I already knew there was a problem and I need to get that other Box apart and get pictures with more detail to zooz. But I do appreciate how helpful everyone has tried to be.