I have 3 wires coming into a single light switch box. One is from the breaker, one goes to the fan (includes light), and I believe the other wire goes to the next switch in the circuit. The single switch currently turns the fan and light. There are no other switches in this room that control fan and light.

The wiring looks like below. I'm trying to replace the single light switch and install a Decora dual switch so I can control fan and light separately with existing wiring. Is it possible? If not, can I add a new switch altogether (cutout the single gangbox and install a two gangbox) with the existing wires so I can have separate switches for fan and light? I'm trying to avoid running a new wire.

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  • 3
    Your problem isn't adding switches. Your problem is that you don't have enough individual wires running from your switch(es) to the light/fan.
    – brhans
    Jul 10, 2020 at 0:06
  • 2
    Are you OK with taking your switch back and getting something else in its stead? Do you mind having to install stuff into the fan canopy? Jul 10, 2020 at 0:14
  • @brhans Okay. Looks like I need to run a new wire after all. I have attic access for this room. How does the wiring look like if get a new 14/3 wire? Thanks for your help!
    – tempid
    Jul 10, 2020 at 1:19
  • @ThreePhaseEel Yes, I can take the dual switch back to the store and get something else. Do you have something in mind? A remote may be? I heard those don't last long. And yes, I can install stuff into the fan canopy. I've installed this fan+light combo recently. Previously there was only one light in this room.
    – tempid
    Jul 10, 2020 at 1:21
  • So you have another light in this room. Is it controlled by its own wall switch and is it by the door? If so, you could wire the light in the fan on the same switch so both lights would be on and off together. The switch in your picture would control only the fan. I assume your fan/light combo has separate neutrals for fan and light, right? Or is there only one wall switch that currently controls everything? Jul 10, 2020 at 2:41

2 Answers 2


You don't have enough wires for a double switch

You don't have enough wires in the wall for a double switch, unfortunately. You'd need a /3 cable (black, red, white, bare) for that, but you only have a /2 cable (black, white, bare), and all the wires in that cable are already spoken for.

Maestro to the rescue!

However, Lutron makes a solution for this problem in their Maestro product line; namely, a fan/light controller that uses powerline signaling to communicate with a canopy receiver module. You'll want to get a MA-LFQM or MA-LFQHW in the appropriate color (WH for white or LA for light almond, for instance), and install it according to the included instructions.

  • 1
    Thank you! At around $60, the Maestro controller costs almost as much as the fan but I'll check it out. I have access to the attic above this room. Would it work if I run a new wire so I can have two separate switches? If so, how does the wiring look like? Thanks again and I really appreciate your time.
    – tempid
    Jul 10, 2020 at 3:32
  • @tempid -- you'd have to replace the /2 cable up to the fan with a /3 cable of the same wire gauge and type Jul 10, 2020 at 11:44
  • Our two new Hunter ceiling fans with lights came with a wireless remote which allows separate operation of fan and light even though there is only one 12/2 cable powering it. This is much simpler than replacing the original /2 cable with /3. Of course, the remote is battery powered and the receiver/switch is more prone to trouble than hard wiring. Check to see if you can get a wireless controller for this fan. The wireless controller allows dimming of the light and switching fan speeds. If you change to a /3 cable you will have to get special wall switches to control fan speed and light intens Jul 10, 2020 at 14:51
  • Hunter fans come with and without a wireless controller in the box, but a wireless controller is available separately. Our two wireless controllers have been troublesome and the receiver in the fan shroud is a pain to install and remove. I much prefer wall switches, but if you have never installed a retrofit box and fished a wire from the attic down into a wall, it would be a challenge. Jul 10, 2020 at 14:59

If you want to wire in the switch you've got you need to replace that two conductor romex with a 3 conductor one (3 insulated conductors plus earth)

Your supply connection (the short black wire from the wire nut) goes to the side of the switch where the terminals are linked by a brass fin

the red and black to the fant-light go to the other side of the switch.

With the 3 conductor wire the red becomes the second switched circuit and goes from the fan switch to the fan while the black goes from the light switch to the to the light. white and ground follow the same path as the existing wires.

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