Bizarre voltages at 3-way lights

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Joseph Skoler

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I am in way over my head.

I have a 3-way light switch environment. Lights are overhead LEDs. It was working fine, then I put in a Zooz (Internet/remote controlled, electronic) 3 way switch at one of the switch locations. I keep blowing the Zooz switches (went through 4 of them).

So I disconnected all wires at switch locations A and B to start fresh. I am not certain where each wire goes (which comes from the line, which to the load, etc.). Pretty sure red at each location is traveler, and bare is ground (pretty messed up if it were otherwise).

But I can't explain the voltage readings I'm getting.

Switch location A:
Bare-White: 37 VAC
Green-Black: 128
Green-Red: 49
White-Black: 83
White-Red: 12
Black-Red: 69

Switch location B:
Green-Black: 0
Green-Red: 49
Green-White: 37
White-Red: 12
White-Black: 37
Red-Black: 49

When I short White to Black at location B, and at location A have red to the traveler terminal of the Zoon, White to the load, bare to neutral and black to line the Zoon functions perfectly (controls the light with the manual switch as well as remotely).

Does anyone know what this could mean?

Thank you.
 

wwhitney

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Your voltage measurements are surely with a high-impedance meter, and are meaningless.

Start by drawing a diagram of each box, showing the number of cables entering the box, and the colors of all the wires in each cable.

Cheers, Wayne
 

Joseph Skoler

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Your voltage measurements are surely with a high-impedance meter, and are meaningless.

Start by drawing a diagram of each box, showing the number of cables entering the box, and the colors of all the wires in each cable.

Cheers, Wayne

OMG, that makes so much sense!

Do I understand correctly that these odd readings are stray or induced voltages, and therefore effectively phantom in nature, on these lines?

I would love to draw a wiring schematic but all I have access to are the boxes. I can't be sure where the wires go.
 

wwhitney

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Almost certainly.

I didn't ask for where the cables go, just how many are in each box, with what color wires.

Wayne
 

WorthFlorida

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Did the Zooz switches blow immediately or worked for a while and then went bad? Are you absolutely sure this is only a simple 2-switch 3 way setup with one or more ceiling lights?

From your voltage reading, BOX A (1) most likely has the power on one of the black wires (128). Box B (2) would be a standard 3 way switch. These are 2 of 3 diagrams from the Zooz site and these are the 2 most common wiring setups. It's why Whitney is asking the number of wires so it is known which box has the load (LED lamps). From your posts, It sounds to me you have the first wiring setup where the power and load are in Box A, but not 100%. Note, one white wire (load connection) in the first picture is a traveler, not a neutral. Pictures would help.

Please takes wwhitneys advice as I'll not be able to post for most of the day.

Screen Shot 2022-02-08 at 9.40.25 AM.jpg
 

wwhitney

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these are the 2 most common wiring setups.
From the OP, it sounds like there's just a single 3 conductor cable in each box. Which would mean that power goes to one of the luminaire boxes first, with drops to each switch location. But I'm awaiting confirmation of that.

Cheers, Wayne
 

wwhitney

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BTW, if it's correct that there's just a 3-conductor cable at each switch location, then with conventional 3-way switching, there is no neutral conductor at either switch location. The Zooz switches appear to require a neutral (at least ZEN23 does), so there's no way to install a Zooz switch by only rewiring the two switch boxes.

There's also no way to install the ZEN23 using a hardwired traveler to the other switch location (without adding more cables in the wall). The ZEN23 with hardwired traveler requires 4 conductors going to it: constant hot, neutral, switched hot, and traveler.

However, if as expected the two switch drops originate in a single ceiling box with a constant power feed (and outgoing switched power if there are multiple lights, so potentially 4 cables), then by rewiring that box also, you could make the Zooz switch work by itself, and provide constant power to the other switch location (with an unused red conductor in that cable). Since Z-wave is wireless, that would presumably let you install a compatible switch that would wirelessly tell the Zooz to toggle, acting like 3-way switching.

Cheers, Wayne
 

Joseph Skoler

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Spent the past couple of hours and thought I had it solved, but I don't.

I'm pretty sure it is, as you expected, wired so that power (line) comes into (what I was calling) location B. Black (hot) is permanently connected to the back wire of a second romex cable at that location. That second romex (I believe) is going to the ceiling lamp box. From the ceiling lamp box, romex goes to location A. The black/hot coming into the ceiling box appears to be tied in that ceiling box to the black wire going to location A.

If at location A I tie the incoming black/hot to the incoming white wire, then I have switch control of the lights at location B.

I thought that this meant that if (at location A) I switch from shorting white to black to shorting white to red, it would give me 3 way control. That doesn't seem to work.
 

wwhitney

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Would you please point a succinct statement of the form:

Box A: One 3 conductor cable (B, W, R, and ground)
Box B: One 2 conductor cable (B, W, and ground), one 3 conductor cable (B,W,R and ground)

Your OP only listed 6 pairs of wires at each box (for the voltage readings), which would imply one one 3 conductor cable (plus ground), as 4 choose 2 is 6. But now you say one of the boxes has a second cable going to it? We can't help you without complete accurate information (at least what you can see, obviously you can't see the cable routing behind the walls).

Also, before you made any changes, there were just (2) 3-way switches, the kind with 3 screws, one a different color from the other two?

Cheers, Wayne
 

Joseph Skoler

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Would you please point a succinct statement of the form:

Box A: One 3 conductor cable (B, W, R, and ground)
Box B: One 2 conductor cable (B, W, and ground), one 3 conductor cable (B,W,R and ground)

Your OP only listed 6 pairs of wires at each box (for the voltage readings), which would imply one one 3 conductor cable (plus ground), as 4 choose 2 is 6. But now you say one of the boxes has a second cable going to it? We can't help you without complete accurate information (at least what you can see, obviously you can't see the cable routing behind the walls).

Also, before you made any changes, there were just (2) 3-way switches, the kind with 3 screws, one a different color from the other two?

Cheers, Wayne

Sure:

Front Box: 1, 3 conductor cables
Rear Box: 2, 3 conductor cables
 

wwhitney

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OK, is the rear box A or B in the original post?

And the rear box really has 2 different red wires, it's not one 3 conductor cable and one 2 conductor cable? That would be a lot more common. If so, do you remember what wires were attached to the 3-way switch, vs what wires were just connected through?

If you are comfortable with a voltmeter and have a low impedance meter or a test load, then I could tell you a diagnostic tree to determine which wire is which, but it will be lengthy.

Cheers, Wayne
 

Joseph Skoler

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OK, is the rear box A or B in the original post?

And the rear box really has 2 different red wires, it's not one 3 conductor cable and one 2 conductor cable? That would be a lot more common. If so, do you remember what wires were attached to the 3-way switch, vs what wires were just connected through?

If you are comfortable with a voltmeter and have a low impedance meter or a test load, then I could tell you a diagnostic tree to determine which wire is which, but it will be lengthy.

Cheers, Wayne

Rear box is location B.

Yes, each of the romex wires are 12/3 (and therefore include a red wire).

I have several digital VOMs but I'm pretty sure they are all high impedance.

Here's more info:

Each location actually has 2, triplex boxes (that is, 2 boxes each with 3 switches in them). The boxes are stacked vertically (one on top of the other).

The bottom boxes function fine.

I think what I should do is open the bottom boxes on both locations and note that wiring, then recreate that wiring exactly for the top box. (Basically, copy what works.) I thought I had done that previously, but perhaps I made a mistake.

I'll report back with the results.

Thank you very much!
 

Joseph Skoler

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Removed the switchplate and the switch holding screws and took the attached pictures.

Seems the top and bottom boxes are not wired the same.

The one that is working fine (the bottom box) has 4 12/3 cables coming in. I believe the right-most cable comes from the breaker, and the other three go to the overhead lights and then down to the other switch location.

The top box has 7 12/3 cables coming in. 4 of the black wires are tied together, the other 3 go to the switches. Same thing for the white wires.

Does this make sense to you?
 

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wwhitney

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OK, so now the story is that instead of each location having a single gang box with one 12/3 cable going to the box, each location has (2) triple gang boxes, one of which, for example, has (7) 12/3 cables going to?

You're in a deep, deep information hole. If you remember how everything was wired up before you touched it, then try putting back both 3-way switches and see if everything works. If you're very lucky, you'll undo the damage you've done. If not, you'll need to get an on-site professional to sort it out.

If you manage to get back to square one, then the way to start is this: the two switches that control the lights you want to put the Zooz on (just 2 switches currently control them, right? No 3rd switch anywhere?), make a diagram for each 3 gang box that shows every device in it, every cable coming into the box, and every connection of every conductor within the box. For example, the diagram for the box with (7) 12/3 cables in it should have 21 different colored (or color annotated) lines coming out of the box (just stubs, since you don't know where they go).

If you do that at each box with the two switches for the lights in question then we should be able to tell you how to wire the Zooz switch.

Cheers, Wayne
 
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Joseph Skoler

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Yea, I'm in doo doo here.

Well, one set of 3 switches works fine and the other works but not as a 3-way.

I'm tempted to give up and focus on solving other problems for now.

Thank you very much anyway.
 

WorthFlorida

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The picture of the Zooz switch, is that a bare copper ground wire to the Neutral terminal? (That is a big No-No) There is no wire on the GND terminal. The black wires on the Zooz switch, one comes from another Zooz switch next to it. That is probably the LINE (hot) lead. Zooz and many electronic dimmers and switches need a neutral. For the electronics to work, a trickle of current is allowed on the neutral wire thought the lights will not be on.

I see three red wires from three cables, are all of these connected to 3 way switches? There is another reason why there is Blk, Red and Wht where the Red would be hot. Two breakers feeding two circuits in one cable with a shared neutral. I won't get into that.

At your place of work or any neighbors have electrical wiring knowledge that can help you here? As you first statement, "I'm way over my head"!
 

Joseph Skoler

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Up here the neutral and ground are one and the same -- the electronics on the switch work fine.

Yes, the black jumpered wire in the bottom box is line.

Each switch has a red wire.

Each of the boxes (top and bottom) are fed from a separate breaker. I am not certain if they share a neutral.

That's a brilliant thing to check. It would explain 7 12/3's coming into the bottom box (one coming in from the 2 breakers (2 hots and 1 neutral); one going out to the top box (1 hot and 1 neutral); one going to the lights; 3 to the remote switches).

I don't know where to go with that assumption/conclusion now.
 

wwhitney

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Up here the neutral and ground are one and the same -- the electronics on the switch work fine.
Negative. It is true that neutral and ground are at the same potential when there's no current flow. The difference is that neutral is used as an intentional circuit conductor to carry load current. Ground is reserved for bonding and should only carry current in a fault. So do not power any loads from hot to ground, only from hot to neutral. That includes a load as small as a Zooz switch.

Cheers, Wayne
 
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