The left of the image (light grey background) is what I have set up so far. The right is what's existing. I now realize there's no neutral to go to the regular switch from the 3 way switch since it gets used as hot.

My only idea would be to run 4 wire romex down from the second light fixture to the second 3 way switch. However that would be very difficult and I'd rather avoid it.

Simply I'm trying to wire the last light switch from the last 3 way switch but don't have a neutral wire at that point.

enter image description here

  • I am trying to connect the second 3 way switch to the last switch. However there is no longer a neutral at that point. Jun 18, 2017 at 16:47
  • Are you trying to use power from the 3-way circuit to install a new isolated circuit?
    – isherwood
    Jun 18, 2017 at 16:48
  • Yes, but there is no neutral at the last 3 way switch. Jun 18, 2017 at 16:51
  • There is no always-hot at the last 3 way switch, nor is there any always-hot wire at either previously existing light fixture. Jun 18, 2017 at 17:25
  • 1
    The thing with the two parallel 12-2 cables is not legal. You have to either use 12-4 there, or pass the 12-3 straight between switches and double back with 12-2 to the lamps. Jun 18, 2017 at 18:21

2 Answers 2


The right 3-way (center switch) has neither hot nor neutral. The three wires present there are:

  • messenger 1
  • messenger 2
  • switched-hot.

Since you have neither hot nor neutral, that far 3-way is dead as far as feeding power off it. You have to go back to the left 3-way.

You also have a problem there paralleling two 12-2's, despite what the illustration shows, you are not allowed to do that.

I would start the whole thing over with smart switches which use radio waves for 3-waying, and simply straight-line hot and neutral through all boxes.

  • Switch-1: Smart-switch master that supports radio comm with a powered (or battery) remote.
  • From switch 1 to lamp 1, black=always-hot, white=always-neutral, red=switched-hot.
  • Inside lamp 1: TOP 12-2 is passthru: black goes to always-hot, white goes to always-neutral. BOTTOM 12-2: Black goes to switched-hot (red wire) and to lamp. White goes to neutral and to lamp.
  • From lamp 1 to 2: TOP 12-2: passthru hot and neutral. BOTTOM 12-2: switched-hot and neutral for lamp 2 only.**
  • Inside lamp 2: TOP 12-2 passes through. BOTTOM 12-2: black is switched-hot to lamp. White is always-neutral to lamp only, do not parallel with top 12-2.
  • From lamp 2 to switch 2: black=always-hot, white=always-neutral, red=capped at both ends.
  • Switch 2: Appropriate smart-switch remote.
  • From switch 2 to switch 3: Black=always-hot, white=always-neutral.
  • Switch 3 and past: normal switch circuit.

** This arrangement is very important because it assures currents are equal in all cables. You can't randomly parallel two 12-2's if you need 4 wires, the diagram you linked is wrong.


I recommend you run a 2-wire cable from the first (leftmost) junction box directly to the second junction box. This cable does not have to pass close to the existing light fixtures, nor does it need to run close to the existing cables.

Connect the power source cable only to this new cable (black to black, white to white). Flip the diagram for the previously existing circuit left-to-right, and power the three-way from the second junction box instead of the first.

Now you have both always-hot power and neutral at the second box, and you can wire your new switch and light without complication.

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