multiway-switchswitch
I am in a situation that is Hot – Switch – Fixture – Fixture – Switch. The Hot is supplied with 14/2, and the remainder romex is 14/3. Both switches will be 3way. I found this drawinng on the internet, but not sure it will work. Do I have to run an additional conductor between the two fixtures? I predict this wiring is not correct. But trying to wrap my head around it, so to speak.
Also found this, which I believe will work but requires an additonal conductor. Any thoughts?
I think you want to leave the kitchen box alone and rewire the 2-gang box like this. I used blue for the white neutral wires:
I followed the color scheme of the existing wiring, with the red carrying unswitched hot in the 3-wire cables. Please remember to mark the white traveler with black tape or paint.
You can re-use the duplex you have, but you might want to buy two new three-ways. You could straighten the tabs on the abandoned one but you have to go to the store anyway.
I sent the power to the further three-way first instead of to the one in the gang box because it saves one wire-nut.
THIS IS A GUESS - This Explanation and diagrams must be confirmed with a tester.
I added this as a comment but I'll go ahead and make an answer so I can post 2 drawings. This is what I think you have going on, I think the original plan was for the circuit to have just 2 switches as classic 3-way, like this:
(Excuse my Paint abilities, NOTE: GROUNDS NOT SHOWN
The Next day, Next week or Next year someone decided to add a 3rd switch, the load end of the original 3-way circuit became the 4-way, like this:
This is one explanation for what I see in your pics, but I can't see everything needed. THIS IS A GUESS AT THIS POINT, using these diagrams as a guide you need to test and confirm the accuracy.
The clues that suggest this explaination to me are the white wire attaching to the common screw in your second pic, and in the first pic a white wire nutted to a pair of black wires. The guess is that's the same white wire. A good first test would be to check for voltage where the white joins the 2 blacks, if my theory is correct that will but hot when the circuit is on and not hot when the circuit is off.
Best Answer
Don't waste your time. Have a /3 cable bypass the lamps.
This is a rather straightforward problem if you aren't trying to snake the travelers through the bulb sockets. I know you imagine some great cost savings in wire by doing that... forget it.
Besides... running travelers through the bulb sockets is pointless, and takes up a LOT of splice space inside the box. The common octagon box doesn't have the cubic inches to spare for those splices. (you need 2.25 cubic inches per wire entering the box, so passing the travelers through just wastes 9 cubic inches, leaving precious few for the task at hand.
Unless you want to do this with smart switches. Then your "/3 for everything" plan is fine.
The drawings above don't work anyway
The upper drawing, I can't believe it was drawn out in "pro grade" quality, since it's utterly incompetent. (Here's a paid JustAnswer this was told to a customer; comedy follows.) With the left switch down, all bulbs are dead (no power enters the system). With the left switch up, your choices are either L2 lit, or both wired in series. "What were they thinking?"
The lower drawing is a is a hillbilly hack to avoid paying for the proper /4 cable, and violates NEC 300.3.
Again, no reason on earth to drag travelers through octagon boxes. Just have a /3 cable fly from switch to switch, bypassing the lamps. Then make the lamp string a "spur" off ONE of the switch boxes, all with /2. And you're done.
Or use smart switches. You need /3 between the smart switch master and all lamps. (black=always-hot, red=switched-hot, white=neutral).