SmartThings Community

3-way dimmer with "Power into Light" configuration


(Juliean Galak) #1

I am trying to retrofit a 3-way smart dimmer into an existing setup. After much poking with a multimeter, it appears the wiring is a “Power into Light” scenario with the light located between the switches (the last scenario on this page: Presence sensor unlock but only 1 door locks back). As a result, only one switch box has a wire carrying “line” and only the other has neutral.

As per that page, the GE dimmer and add-on switch can’t be used, but it suggests that the Zooz or Caseta dimmers might. Anyone have experience with this setup? How does one wore it?

It’d prefer a Zwave/Zwave Plus dimmer, but I’m willing to try about any option…


(DavidK) #2

You can use zwave association, so 2 zwave plus switches. 2 of the Ge zwave plus dimmer model #14294

It sounds like your wiring is like mine, missing a neutral in one box.

I use the traveler to send a neutral over to the other box and one switch controls the other using zwave association. So this bypasses both the cloud and the hub.

When I originally set this up in 2015 “linear” brand for the wireless controller switch was current technology.

Those same linear switches are now the previous generation.

I just purchased one of the new Ge zwave plus dimmer model #14294 to see if it is suitable as a replacement for the linear auxiliary switches.

I have been playing with it and it seems that it is probably suitable as a replacement for the linear switches.

As you press on the paddle the controlled switch dims in real time.


(Michael) #3

Please take clear pictures of both boxes where we can see all the Romex wires coming into the box. Depending on the number of wires there is a slight chance of hope if you have access to changing wires at fixture.


(Juliean Galak) #4

I don’t really have the ability to rewire any of the boxes. The lights are high hats buried in a ceiling, there’s no access from above.
(1st floor ceiling of 2 floor house). I’m not willing to open up walls to pull new wiring.

Not sure what photos will tell, but the measurements seem to exactly match the last diagram in the link above. Here’s the image directly:

The only differeence is that some of the cabling is different colors and there’s actually 8 lights (LEDS) wired in parallel.

ETA: Oh, the other important difference is that the left switch box also has access to a neutral wire from panel (since it’s a multi-gang box and has other switches in it). That neutral is not in use at present but can be for a smart switch.


(Michael) #5

Are the other switches on same circuit? What I am trying to confirm via pictures is which Romex wires are hooked up to each switch. I am looking to see if you have a 14-3 Romex with Red, White, and Black wires from that Romex all hooking up to the same switch in each switch locations. Or if other Romex wires are at play. Without pictures I cannot provide any additional guidance.

If you do indeed have power to light your options are very limited and outlined in the FAQ. These require a relay in the fixture.


(Juliean Galak) #6

The left box has a 4 wire romex. Black, white, red, bare. With both switches removed and power turned on, there is 110V between the white wire and the ground (bare) wire.

The right box has a four wire romex, in which the black and red connect to the black and red in left box. The white wire is connected to a large bundle of white wires and has continuity between the bundle and ground. There is another, three wire romex, in which the white wire is also connected to the large neutral bundle. The black wire in this romex has continuity with one of the wires in a light fixtures.

I can’t get to the wires of the light fixtures, but going to the light socket, one side is continuous with the black wire in the three wire romex above, and the other side is continuous with neutral/ground.

So, in effect, I have line only in the left box (white wire) and neutral only in the right box and light fixture. There are 2 wires connecting the two switch boxes (black and red). From what I can tell, that’s not enough to send line or load one way, neutral the other way, plus the traveler wire…


(DavidK) #7

This sounds like my scenario. I have 3, 3 ways, each has line in one box and neutral in the other.

Placement of load switch is important. Needs to be in the “other” box, not the box that the line comes in on. Otherwise turning off the light, also turns off the “auxiliary” switch.

You can use this device handler to set up zwave association. Then once setup, set device handler back to “dimmer switch” so everything runs local.


(Michael) #8

In the US wire colors don’t matter and are not regulated by code. Since there is only one 14-3 Romex (ground bare wire isn’t included in count) in the left switch we can ignore that for now. I am still very curious to see the right box. Just because the wires are white doesn’t mean they are neutral. Please either post a picture or describe each wire currently hooked up to that switch. Pay attention to which wire is hooked up to the bronze/black common screw and which Romex wire that is going too. Is that Romex the same as the two other wires hooked up to that switch. I am honestly trying to help but I cannot see the box. There is a chance you may not have power to light scenario.