Electrical – Is It Possible to Control 3 Light Fixtures with 4 Switches?

electrical

I have an idea how I would like to tackle some wiring I am about to do, but I am having trouble figuring out how to actually wire it all. I was hoping some of you could help me out.

Here's what I want:

I have 3 fixtures, Lights A, B and C.

I have 4 switches, Switches 1, 2, 3 and 4.

Switch 1 turns on/off lights A/B.

Switch 2 turns on/off lights A/B.

Switch 3 turns on/off light C.

Switch 4 turns on/off lights A/B/C.

Is this even possible to accomplish?

Best Answer

This is possible using standard electrical wiring devices! You will need (in addition to standard electrician's tools and supplies):

  • Three three-way switches (switches 2, 3, and 4)
  • A four-way switch such as a Leviton CSB4-15T or equivalent (linking for the sake of those who have never bumped into one, a good home improvement store should have one kicking around somewhere) -- this will be switch 1
  • A two gang box for switch 4, with a switch + blank two gang faceplate -- one side of this faceplate has the standard switch slot, the other is blank.
  • And lots of 14/3 NM-B (in addition to 14/2) because you'll need to run multiple travelers

The wiring diagram is as follows: Hookup for three three-way and one four-way switch to achieve what the OP wants

Dotted lines are neutrals, the rest of the colors are self-explanatory. Three things:

  1. You will want to use a two-gang box for Switch 4, as the wire fill (eight wires) is too dense for a single gang. Perhaps you could stash a wiring diagram in there for the sake of anyone who has to fix it later, too?
  2. Keep your travelers consistent: in the diagram, red is up and black is down, always.
  3. Make sure the documentation for this is kept well, otherwise it will give the next electrician who encounters it a bit of a headache.