I'm trying to upgrade my switches to Enbrighten Smart Dimmers (that require a neutral). I've been successful in one three-way situation, but not in this one.

Original Wiring

(I’m going to refer to the three-way switch terminals as A, B and C, where C is the common.)

There’s 14/3 Romex going into box 1 with a three-way switch. White to the common terminal C, black and red to the other two. Near as I can tell, white is hot.

Box 1

In box 2 there are three red 12 ga wires connected to a three-way switch.

Box 2

Box to inside top

The light fixture has two sets of 3 12 ga red wires. Two pass through into the other, and one from each set connects to the lights.

Light Fixture

[![Light fixture sraight on][5]][5]

With the wires in box 1 completely disconnected and power turned on, in box 2, the AC voltage detector beeps for the red on A or the red on B, depending on the switch position (if A is connected to C, it doesn't beep; same with B), but never beeps for the common red C.

First Attempt

I can get the smart switch to power on if I connect it in box 1 black-to-neutral, white-to-line (and I set the box 2 switch to position B), but I can't get it to turn on the lights regardless of where I connect the other wire (load or traveler terminal). Maybe tomorrow I'll crawl under the house to try to see where the Romex goes.

  • Can you post a photo looking at the inside top of the 2nd switch's box please, as well as one looking squarely into the ceiling box? Dec 30, 2021 at 3:17
  • @ThreePhaseEel I added the photos, such as they are. They were astonishingly hard to get. Lemme know if you can't see what you were looking for.
    – Rick
    Dec 30, 2021 at 7:27
  • Yeah -- can you find where that NM cable from Box 1 goes? Also, do you have access to a multimeter? Dec 30, 2021 at 12:12
  • Yeah, when the rain stops I’ll go under the house to see, although it might go up; if so, that crawlspace will be very hard to access. Yes I have a DMM, but had a hard time getting a credible picture of what was going on (induced currents confusing matters). Lemme know what I can measure!
    – Rick
    Dec 30, 2021 at 12:14
  • 1
    Turn the breaker for the circuit OFF, then set the meter to "continuity" and ring out the wires in switch box 2 + the ceiling box to the box itself (which should be grounded due to being wired in conduit) Dec 30, 2021 at 12:16

1 Answer 1


Thanks to @ThreePhaseEel, who suggested I ring out each wire, I now know that this mess is this:

Final wiring diagram

Neutral to the light box, white is hot in box 1 (really???), and the rest pass through. I guess this is a “switched hot?” I really hate the short cuts taken to save a few bucks.

I think I can distribute neutral and hot to both boxes, but the person doing the original work didn't leave enough in the pass-through to pull out and cut. So I'd have to pull new wire through the flex from box 2. I gave one of the wires a tug and it seemed to pull fairly easily.

Now I just gotta figure out if the Enbrighten “Add-on Switch” can work with the Enrbighten Dimmer.

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