My client's new fan is installed on a 3-way switch above stairs. The switches are located top and bottom, on separate breakers. The fan and light are operated simultaneously. The light attachment has an on/off toggle, and remains off. There are no pull chains. Simple yet unfinished.

Modern Fan Co 'Stratos' included single pole, single-gang fan + light control unit. I'm guessing this will not accommodate, unless I convert to single pole. They offered one 3-way option, while also recommending Lutron (90$ each I believe).

In a nutshell:

  • Are two 3-way single-gang dimmer + fan controls necessary?
  • Is snaking necessary?

I'm not clear if the current wiring (3-way, 3-wire) would support 4 different controls (via single gang, two locations).

Would I need to snake additional wires? Upper would be more practical from attic. Lower may increase difficulty, and most likely be out of budget.

The supplier's tech-guy practically threw his hands up in the air and recommended a remote, unfortunately the manufacturer suggested against this.

I often defer unknowns to professionals when I have multiple clients waiting. I feel like nothing is out of my league. I've installed 40+ fans in my lifetime, and I'm confused here.

Spending more than a few hours on this install is unacceptable by my standards. Therefore I'm setting some time aside to educate myself, and avoid costs.

Explaining this to clients and salespersons can be strenuous. Any input is greatly appreciated!

  • I hope I am misunderstanding: You have 2 3-way switches operating the same fan on separate breakers?? Can you explain/clarify/draw a diagram please? You don't say, but can I assume you are trying to control the light and fan separately? And does that need to be 3-way control? What wiring exists at each switch location? (there should be a 3-conductor between the two switches, and one or two 2-conductor wires to the fan or breaker, or if you're lucky, a 2-conductor from the breaker and 3-conductor to the fan) Do you have one of these controls? – gregmac Jun 18 '13 at 16:23
  • Yes the product description of the 'Dimmer + Fan Control' is a standalone unit designed to fit a single gang box, seperating fan and light controls. – Casey Jun 18 '13 at 16:30
  • Product is #002 from link. I was also confused referring the multiple breakers when testing. The homes are centennial so I'll accept their flaws and use them to learn. 3-conductors exist at both switches. A 3-way multi-control at both locations is ideal, is it possible to install one at the upper, and leave standard switch at lower? When I say 4 controls, there are 2 per unit (gang), fan speed and light dim. – Casey Jun 18 '13 at 16:59

I don't think it's possible to get everything you want because of the 3-way requirement. There is no true 3-way dimmer setup with double throw switches. The ones promoted as such use electronics to detect the change of state in the satellite switch and mimic 3-way operation. Such a setup may or may not work with your current wiring, you would need to refer to the installation instructions for a specific device.

And even if the pseudo 3-way dimmer is made to work, it cannot be done in a single gang box, the fan control would need it's own box. The closest scheme I can imagine would require a double box at one end with the sole fan control and a separate dimmer control. The other end could be single gang to contain the dimmer satellite control. No fan control would be possible from the satellite end. Even so, you are likely a wire short between fan control and fan, but it's not possible to say for sure without detailed information on all the devices involved.

With most fans available today, it's unlikely to be able to switch the light and fan all with a single pair of 3-way switches. The typical fan needs it's own dedicated speed control. As it's controlled electronically, it's not even possible to set the speed to maximum and then toggle it on and off with a wall switch. When you cut the power, the fan "forgets" it's status. When power is restored, it most likely will default to the off state. And the fan would never work on a dimmer controlled circuit no matter what.

There are other possibilities, but in each case, you will need to give up one or two things, either single gang, dimmer control, use existing 3 wires, or 3-way control. Depending what you would be willing to give up, a solution likely exists. You just can't have it all.

  • Lutron makes exactly what the OP is after -- its just his wiring has issues in it that mean he'll have to rewire the thing anyway to get it up to Code so that he can use what Lutron makes for this job... – ThreePhaseEel Nov 13 '15 at 23:32

The good news is that Lutron makes a combo fan/dimmer setup that can be used in 3-way applications: you need a MA-LFQM kit and a matching MA-ALFQ35 accessory control.

The bad news is that your existing wiring setup appears to be a 2-circuit Carter 3-way, which is prohibited by Code due to the shock hazard it poses.

Carter 3-way diagram, by Wtshymanski/Wikipedia

(source: Wtshymanski/Wikipedia). This wiring system is also utterly incompatible with 3-way fan controls/dimmers such as the Maestro parts linked above, so you'll have to snake a new set of travelers between the boxes using 14/4 (as switch boxes need a neutral wire now) in addition to disconnecting the 2nd circuit from the 3-way setup.

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