I work from home in a house with roommates and I would like to set up a light system to let them know if it's OK to disturb me during my work. I was thinking a stoplight system of Red: Do not disturb unless it's an emergency; Yellow: you can come in to get something, or if you need something quick / important; Green: consider the door open, feel free to come in and chat or whatever.
I'd like to have these lights place outside the door, and a 4 position switch on my desk that would have: Red, Yellow, Green, Off on it.
- Can I wire the neutral of all the lights together so I only have 4 cables running from the switch to the lights, or should they each have a neutral running back to the switch?
- Do I just hook the power to a specific terminal of the switch, and then have 3 different power lines (each from positions 3-1) out with one neutral running back and position 0 empty?
- Do I need any sort of adapters if I'm going to run 25w incandescent bulbs?
- Am I missing anything else?
I've been looking around for switches and think I found what I wanted in this switch, although I'm certainly open to suggestion. It's important to me that the switch be large enough that the space between positions is enough for them to be labeled and for it to be obvious to an observer which position the switch is in. I think what I'm looking for is a 3 throw knife switch, but I don't think one exists. Perhaps I could just do a 2 throw, and have a Red / Green / Off? Or maybe use a 2 throw for the RYG, and then a separate kill switch that turns it all off?
Theorized image: 
Best Answer
your drawing is exactly right, except that there should be no breaks in the grounded (neutral) conductor, and that you'll likely have to have a grounding conductor throughout the circuit as well. You should also be able to find a rotary switch with 3 positions plus off, though it might be a bit pricey.
So your wiring could look something like this