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I have two three-way switches controlling two lights in my laundry room at either entrance. I want to remove one altogether and replace the other with a Kasa motion sensing dimmer switch which is single pole and requires a neutral.

On existing switch 1:

  • incoming 14/2 black and white. When testing the wires, white is energized, black is not
  • outgoing 14/3 red,black and white White incoming and outgoing are connected
  • black from 14/2 is connected to common
  • Red and black from 14/3 are travellers

On existing Switch 2

  • incoming 14/3 Red and black are travellers, white to common

I have tried every possible combination of things i can think of without success. I want to eliminate switch 2 altogether and just use switch 1 as a single pole. I cannot determine if the power is incoming to switch 1 from the lights or if switch 1 is where the power comes in. Since the white is energized on the incoming 14/2, I’m thinking it is but there is no access to that in the ceiling…

Help!

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  • I'm not a code expert, but I'm 99.999% certain that you need to have a light switch at any and every entry to a room, even if there are "smarts" that will turn the lights on from the other switch. Plus, unless you remove the cable from the wall, you'll still have to have a blank plate at the removed switch, so you may as well just leave the switch there.
    – FreeMan
    Feb 5 at 13:43

2 Answers 2

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I want to remove one altogether and replace the other with a Kasa motion sensing dimmer switch which is single pole and requires a neutral.

You don't have a neutral at either switch. You'll need to leave the existing switches, or find an appropriate product for the purpose, or rewire the light and switch.

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I believe you have the following:

Power comes in to one of the light fixture boxes.

  • Hot (black) connects to white going down to Switch 1.
  • Neutral (white) connects to neutral on the fixture.
  • A separate black/white cable extends switched hot (black) and neutral (white) to the second light fixture.
  • The cable going down to switch 1 has white (hot, noted above) and black (switched hot)

Switch 1 box has:

  • Black (switched hot - common from switch 1)/white (hot) from the fixture box.
  • /3 cable between switches has black and red (travelers) and white (continues the switched hot from the fixture box to switch 2).

Switch 2 box has:

  • Black and red travelers and white hot (from fixture box -> switch 1 box -> switch 2 common).

The end result is that switch 1 does not have neutral. There are really only two ways to fix this:

  • New /3 cable from fixture box to switch 1 to also carry neutral. This could be trivial or hard depending on whether the wall/ceiling are open or not.
  • Smart switch that does not require neutral. Normally this means it needs ground, but you can't make that decision on your own. There are very strict limits of how much current a switch can get when connected to ground instead of neutral - i.e., it has to be officially UL or ETL listed with "no neutral" as an option.
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  • Ok so I opted for the “ no neutral” choice…. So now the big question - which switch box makes the most sense to attach to? Either is ideally positioned for motion sensing….
    – Chris
    Feb 5 at 21:42

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