# 3 Way Switches with Single Power Source

I have two switch boxes, each with two switches for living room and kitchen lights.

Box A has: 14/2 power source 14/3 run to box B (living room) 14/3 run to box B (kitchen)

Box B has: 14/3 run from box A (living room) 14/3 run from box A (kitchen) 14/2 run to lights (living room) 14/2 run to lights (kitchen)

Can I make this work with 3 way switches?

• Are you saying power enters box A, then there are dual 14/3 cables between box A and box B? Sep 5, 2022 at 20:26
• The 3 ways always have one master and one slave. The master is the one where constant power comes in. From there the 3 way switch sends it to the second 3 way. The slave had two wires coming from first switch, and one wire going to the load (lamp) Sep 5, 2022 at 20:42

3-way circuits are pretty straightforward, but looking into that box will be like gazing into the mind of Cu'thulu unless you do something to de-confusify it.

OK, you'll need a 5-pack of colored electrical tape.

Start at box B. Take red/black from one of the two /3 cables, and wire-nut them together. Now go to box A and find the /3 cable that measures zero ohms between the red and black, that is the same cable you just wire-nutted. Wire-nut that red/black also. We're just identifying which cable is which.

Now box A and B have a 14/3 that is NOT wire-nutted. Using the colored electrical tape, spiral-wrap the red and black wires YELLOW in both boxes. These will be travelers for group 1. This marking is essential if you want this wiring to be easy mode. Feel free to "not do it" but don't blame me if you go mad lol.

OK, with yellow marked on both ends, now remove the wire nuts and mark the other /3 cable's red and black wires with BLUE electrical tape. Travelers, group 2, alternate color. Now as a bonus thing, it would not hurt to mark that cable's white wire with GRAY tape. It is vital to keep the neutrals separated in box B.

I'm just picking the colors common in 5-packs of colored electrical tape. I know there are sets with orange instead of yellow, that's fine.

Now in box B, you have two /2 cables that will be "switched-hots" going to the lamps. Mark one red, and maybe leave the other unmarked. We're kind of out of colors :)

At box A, you will need to pigtail supply black to two pigtails to go to the switches.

Then the whole shebang wires just like the above diagram, if there were also a second diagram with blue travelers.

Note that neutrals must be kept carefully separated in box B. Pick any switch, follow the wires to it back to their cables. The neutral wires in those cables only, are grouped with each other and with nothing else. So you will have 2 neutral groupings.

Do not simply nut all the neutrals together in box B.

Do nut all the grounds together, and also to the metal box if it's a metal box.

• Thank you. At box A, what do I do with the white from power and the whites in the 14/3’s? Would I tie all 3 together in box A? Sep 5, 2022 at 21:58
• @user156220 yes, neutral needs to be carried through from supply to the neutrals in the two 3-way runs. So they are just joined together. Sep 5, 2022 at 22:24