I have an existing 3-way switch setup that I'm trying to convert to "smart" switches and I'm feeling "not smart" after mapping out where I think the wires are going. Unfortunately I don't have a good wiring diagram to share with you besides this back of the napkin drawing where yellow = white wire.
Box A: This is a double gang box. There are 2 switches and 4 cables in this box. The first switch is a leg of the 3-way switch to entryway chandelier (20 feet overhead, I have no access to the fixture box so I don't know how it's wired). The other switch (referred to as switch 3) is to an outside light. I only mention it for completeness and the fact that it's using the same 14/2 line as the 3-way switches of interest.
Box A two gang cable 1 - 14/3 romex black - switch 1 traveler (switched hot) red - switch 1 traveler (always hot) white - nutted to cable 2 red cable 2 - 14/3 romex black - wired to switch 1 oddball/common terminal (always hot) red - nutted to cable 1 white white - neutral cable 3 - 14/2 romex black - line (always hot) white - neutral cable 4 - 14/2 romex black - switch 3 load (to outside light) white - neutral (from outside light) all neutrals in box nutted together (cable 2, cable 3, cable 4) cable 3 black (line) nutted to: (cable 2 black, switch 1 oddball, switch 3 line)
Box B: This is a single gang box. There is only 1 cable in this box. This is the other leg of the 3-way switch to entryway chandelier. Presumably this cable is the other end of cable 1 in Box A, since when the circuit is off that wire behaves the same in each box (red is hot, black and white are off).
Box B single gang cable 1 - 14/3 romex (presumably other end of Box A wire 1) black - switch 2 (switched hot) red - switch 2 (always hot) white - switch 2 oddball/common terminal (switched hot)
Okay... so now my question is ultimately twofold: What is most probable wiring diagram for the chandelier fixture box, and can I rewire for a smart switch & add on without having to change the wiring at the fixture?
I am presuming that Box A cable 2 is going up to the fixture. If that's true, I'm at a loss as to why 14/3 is used for this purpose.