I have a single-gang switch box (12.5 cu) that has 3 14/2 wires inside of it. I would like to re-wire the switch to be a 3-way switch.
As far as I can tell, the 3 wires are power to the box, power from the switch to the lights and then a 3rd power line to additional outlets (I have yet to 100% verify this).
I was hoping to run 14/3 from the existing switch to the new one and leave the old wiring to the lights alone. That being said, by my count the 3 wires alone should be in a 20.0 cu box so adding in a 4th would be a bad idea.
What alternatives do I have? Do I need to wire the 3-way switch through the lights and to the new switch?
Any guidance is appreciated.