Box one. I'm doing a remodel and want to add a fixture to an existing three way, it would be a ton of work to reach the existing fixture or the three way switch that has the power supply in it's box. My question is can I, or how do I add a fixture off the other switch location.
You can't. Not with steam switches.
You will need to switcheroonie over to "smart switches" for this to work.
You will need smart switches that communicate either wirelessly or via powerline signaling. You won't have ANY spare traveler wires.
On the inter-switch 3-way cable, you will reassign all 3 wires to new jobs, which will be obvious.
- White = neutral (smart switch and lamp need this)
- Black = always-hot (hot at all times, the smart switch needs this)
- Red = switched-hot (hot when the lamp is on)
Both lamp hots get attached to the switched-hot wire.
Both lamp neutrals get attached to neutral obviously.
One of the smart switches attaches to always-hot, switched-hot and neutral.
The other smart-switch attaches to always-hot and neutral.
Often the layout of the 3-way circuit dictates where the master must be - but not this time. You can have the master in either location here.