Controlling A Ceiling Fan with X10

by Doug Felteau on January 18, 2006

This article reprinted courtesy of Smarthome.

I’d like to control a room fan that is hooked up to a wall switch using X10. I see X10 wall switches in your catalog, but they are only for lamps. Is there an appliance wall switch available? Controlling fan speeds would be best, but I’m happy to just remotely turn it on and off.

These observations about most of our switches being primarily designed for incandescent lamps is correct, but we do have some models that can control ceiling fans and small motors. Many times we hear from folks who bought an X10 wall switch somewhere else and they can’t get it to work with a ceiling fan. Sometimes, they can get it to work, but the operation is unreliable or the fan’s motor produces a humming sound.

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Regular X10 Switches for incandescent lights only

Most of our entry-level switches, read that as “cheap”, are only designed to work with incandescent lights. Without getting too technical, the designers of these switches rely on the electrical properties of a good-ole filament light bulb to make the X10 switch receive commands from the power line. Basically, the X10 signal must travel through the light bulb’s filament to get to the switch. When something other than a standard incandescent bulb is connected to the X10 switch, the signals are blocked and the wall switch doesn’t react to incoming X10 signals. The wall switch continues to work normally by manual control.

These wall switches are easily identifiable. Printed on the front of the switch will be a rating describing the kind of load it can work with. Pictured on the side is the classic X10 wall dimmer with markings identifying it for use with only incandescent lights. We also mention the loads each switch is rated to work with on our web pages. We also have a comparison chart of all our wall switches on the web site that breaks down the loads controllable by each switch. Check it out here: X10 Smart Switches

Special switches for ceiling fans

For those of you who want to control a ceiling fan, we do have just the right switch for your project. These switches have been specially designed to work with additional load, like a fan’s motor. There are two types to choose from: an appliance type model that will turn the fan on and off, and a dimmer model that will enable the user to essentially vary the speed of the motor. There are a few issues to using these switches that need to be addressed. We mentioned them in the descriptions on the web site and catalog, but I’ll explain a little more so you can make an informed decision.

Neutral wire requirement

Click to see a larger image Switches for loads other than an incandescent bulb will have one additional wire a basic X10 switch lacks. Where a simple X10 dimmer for incandescent lights has two hookup wires, (Line or the incoming power and Load or the outgoing power), switches for non-incandescent loads have a third neutral wire. With incandescent switches, the X10 signal must travel through the bulb in order to complete the circuit. Because the ceiling fan’s motor blocks those signals, we need a way to get the X10 signal through the switch. The neutral wire is our answer.

Checking for a neutral wire

Before ordering switches that require a neutral wire, you’ll need to check that your home’s wall boxes have a neutral wire inside. Most homes built in the last 30 years are likely to have a neutral wire in the wall box, but you’ll want to check to be sure. In many parts of the country, electricians are required by building codes to wire the circuit so that the neutral wire is located in the wall switch box. However, we often hear from customers that their newly built house lacks a neutral wire in the wall box. If you are building a new house, be sure to check out our recommendation here: Wiring Your Home for Automation

Click to see more! With normal mechanical wall switch, only the Line and Load wires are used. Checking for a neutral wire is pretty easy just follow these steps:

  • Turn off the power to the switch at the circuit breaker
  • Remove the trim plate screws and plate
  • Remove the two screws that hold the switch to the electrical box in the wall
  • Carefully pull out the switch from the wall box
  • Look for a group of wire wires connected together with a wire nut

If you see the white wires in the back of the box, then your have neutral wires for the new X10 switch to connect with. If there is only a single white wire connected to a terminal on the switch, this is most likely not a neutral wire. Since neutral wires are not connected to mechanical switches, they will be pushed to the back of the electrical box and tied together with a wire cap. Please note that the bare copper wire is the ground wire and should not be mistaken or used for the neutral wire.

Choose a switch for your fan

Now that you have verified that a neutral wire is present in the wall switch box, you need to choose the switch for your needs. Switches for ceiling fans will come in two styles; on/off or on/off with dimming. A ceiling fan can be controlled with a dimmer, but this comes at the cost of an inconvenience.

Dimmers for ceiling fans

Most ceiling fans sold over the last few decades are not designed for operation with a dimmer. They either expect the full 120 volts or nothing. X10 type dimmers contain an electrical component that when dimmed, will chop off a portion of the electrical sine wave. With a light bulb, this chopped-off sine wave results in a dimmer light, but with motors, it often results in a humming noise coming from the fan. The audible humming from the fan’s motor may be distracting to the room’s occupants. We have observed that some models are worse than other. Here are a few conclusions we have drawn:

  • The more expensive the fan, the more likely it is to hum.
  • Cheaper models are less likely to hum.
  • Motors with “shaded pole” and “permanent split capacitor” produce the least amount of hum, if any.

There are some things you can do to minimize the noise from a ceiling fan’s motor. We have found that the better quality dimmers when connected to ceiling fans produce less noise than the entry-level model. The SwitchLinc Lite #2384, Leviton Enhanced Dimmer Switches #2203 & 2209, and the X10 Scene-Setting Smart Switches #2367 are the best ones to choose when humming is a concern. Click to learn more about filters.

You can also install a filter on the output of the dimmer switch. The filter acts like the shock absorbers in your vehicle by smoothing out the chopped with sine wave of the electricity. This “smoothed-over” electricity going to the fan will help reduce the hum. Additionally, if your fan has multiple speeds, you may find that one of the settings is better than the others. A little experimentation here will alleviate some of the hum.

Non-dimmer switches that don’t cause hum

If the humming is a concern for your application, choose a non-dimming switch. These switches are either on or off. That is, just like a regular mechanical switch supplies a straight un-modified 120 volts or it doesn’t (in which case, it’s off). On the side is a picture of our best selling non-dimming X10 switch, the Leviton 15-Amp Wall Switch Module #2206WI.

It is rated to work with just about anything up to 20 amps, so a ceiling fan is no problem. Just like the dimmer models, it requires a neutral wire in order to operate. This switch operates like an X10 appliance module; so don’t be surprised when you hear it click when it’s turned on or off.

It is possible to keep your cool by automating your ceiling fans. If you look back to Ask Laddie #26, we automated a window air conditioner. That same project would easily of automated a ceiling fan to come on when the temperature rose beyond a desired level.

Posted in: Home Automation
Insteon software Jan 7, 2010 at 12:55 AM

Nice article! I think at least two people I know have put normal dimmers on their fans only to have them burn out in a few weeks. I'm getting started with using software now and it's been interesting and frustrating at the same time!