Which Neutral for a Single Pole Leviton Dimmer?

Question

See picture to help understand situation.

I am trying to install a Leviton Decore Smart WI-FI dimmer ina single pole application.

The box I’m working on has an existing 3-way switch working fine. There are three holes in the top which all have ground, neutral and black wires coming from. There are two holes in the bottom, one with black/white wire, and another with white/Black/red (for the 3-way).

The switch I’m replacing has it’s hot black wire coming from a wire nut joined with two other black wires and a white wire.

There’s another wire nut with the remaining four neutrals tied together.

I’m tryinf to figure out which neutral I should tie into the single pole switch I’m installing (it requires one). I tried tying all four neutrals into the switch and that didn’t work. It gave power to the switch but I couldn’t factory reset switch or operate lights, they would sometimes flicker when I activated the air gap.

Any ideas? Thank you!!!

Answer 1

The neutral is the bundle of white wires.

The "3 hot 1 neutral" is not a neutral at all. It is a white wire which has been repurposed as a hot. Think that through: a case where color does not depict function.

It's not the only one: the line north from the 3-way is a switched-hot that I prefer to mark red since it's switched-hot, and the red-black pair leaving the 3-way are messengers I prefer to mark yellow.

Code, however, does now require you mark your re-purposed neutrals. Before it was allowed to not mark them if the usage was obvious. Which was a pretty editorial threshold, as you see!