I'd like to add a neutral wire to an old switch box so that I can install a smart switch that needs a neutral wire.
I have a mud room and porch that each have a light fixture. The lights are independently controlled by a pair of stacked switches. Both fixtures are on the same breaker.
The wiring is old, and there isn't a neutral wire in the switch box.
I need to verify this, but I'm pretty sure 3-wire cable brings hot, neutral, and ground up to the junction box for the mud room light, and from there the same to the junction box for the porch light.
I think that neutral is then run in each junction box to each light fixture. The hot is then wired with 3-wire (including ground) cable to the switch box, which sends switched-hot back via the same 3-wire cable, to connect to the hot side of the light fixture.
I'd like to replace the stacked switches with a single smart switch that controls both lights (so that they would turn on/off together rather than being independently controlled).
My idea is to run hot/neutral to the switch box via the cable that currently is being used to switch fixture 1. The cable that is currently being used to switch fixture 2 would continue to supply the switched hot that is necessary for fixture 2. The cable that is being used to take neutral and hot from fixture 1 to fixture 2 would then be repurposed to take the switched hot from fixture 2 to fixture 1, and to take neutral from fixture 1 to fixture 2.
Does this sound code compliant, and aside from code compliance, does it sound like a reasonable idea?