How To Wire A Fan Control Switch

By Vernon Trollinger, May 19, 2017, Home Improvement

Welcome to the How Do I Do This? series from Bounce Energy. Each month, we’ll dive into what it what you need to know to shop for, install, or repair those things in your home to keep your life affordable and convenient. Plus, you’ll (hopefully) learn some useful tips for other projects along the way.

How To Install/Replace A Fan Control Switch

In our last installment, we went over how to retrofit or install a ceiling fan. For the most part, wiring up the control in the wall receptacle are pretty easy. But for some homeowners, what they find in that wall receptacle can be pretty confusing and intimidating. To help make sense of that tangle of wires you might find, we’re going to talk about wiring up and installing the fan control switch.

Can I use a regular light dimmer switch on a ceiling fan?

NO. Fan controls and light dimmers do two different jobs. Light dimmer switches work by raising the electrical resistance which in turn reduces the voltage and so dims the light. AC motors are totally different from lights and DC motors. They are controlled in several ways that include altering the frequency of the electricity with an inverter and using pulse-width-modulation, or adjusting the “slip” of the motor. Using a light dimmer switch will make the fan hum loudly and cause the dimmer to heat up. AC motors all draw a little extra current when they start up. By using a light dimmer to restrict voltage, it can cause the switch or the ban to burn out.

How To Install/Replace A Fan Control Switch

Light dimmers and fan controls are clearly marked, both on the packaging and on the switch that they are for lights or fans.

For light dimmers, you want to match the total wattage of the lights you’ll be using to the dimmer’s wattage rating. Dimmers say for “incandescents and halogens only” but you can use CFLs and LED bulbs IF they are dimmable.

How do I chose the right kind of speed control switch?

To chose the correct fan control switch, check the amperage on your ceiling fan. Most ceiling fans use less than 1 amp so it’s best to use a control dimmer that’s a little higher, like 1 to 1.5 amps. If you’re setting up multiple ceiling fans to one controller, you’ll need to add their amps together and get a control that matches their total. Be sure to set the fan’s speed (usually at the pull chain) to the highest speed to avoid problems with the new control switch.

How to Wire The Control Switch

Basically, all you’ll need to do is to swap out the existing switch and connect the new fan control switch. New fan switches come with two black leads (load) and one green (ground). Usually, it doesn’t matter which black lead you connect to the black conductor wire going to the fan load or line. The switch will work either way.

Follow these steps:

1. Turn off the circuit breaker for that circuit at your breaker panel.

2. Remove the faceplate and pull the switch from the wiring box. Disconnect the black conductor wires and bare wires from the old switch and remove.

How To Install/Replace A Fan Control Switch3. Typically, two romex cables enter the wiring box. The sheathing is stripped off the cable so there can be 6 wires inside the wiring box. Two are black conductors, two are white neutral wires, and two bare ground wires.

4. The white neutral wires are probably connected with connecting caps. Leave these alone.

5. Using a wiring connector cap, connect one of the black conductor wires in the wiring box to one of the black wires on the new switch. Do the same with the other black conductor to the other black wire from the new switch. Be sure that there’s no bare wire exposed from either of these conductors as it could easily cause a dangerous short. Do not over tighten so that a wire pokes through the end of the wiring cap.

How To Install/Replace A Fan Control Switch6. Connect the bare wire to the green grounding wire from the new switch.

7. Carefully fold and push all the wires back into the wiring box.

8. Mount and align the control switch onto the box. Install the screws to hold it in position.

9. Reattach faceplate.

10. Turn on circuit breakers.

11. Test fan.

There’s only three wires inside the box! Now what?

When the power supply connection ( or “line”) is made in the ceiling wiring box, electricians will run a single romex cable down through the wall to bring power to the switch. Known as a “switch at the end of cable run”, line power connects to the white wire and leads (through the romex) to the switch.

How To Install/Replace A Fan Control Switch

Black tape on the white wire indicates it is being used as a conductor.

The black load wire takes the electricity back to the fan. Uniform wiring code requires black electrical tape on the white wire to indicate that white wire is a conductor and not being used as neutral. For connections, treat this white wire with the black tape on it as a black conductor wire and connect it to one the switch’s black wires.

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A native of Wyomissing Hills, PA, Vernon Trollinger studied writing and film at the University of Iowa, later earning his MA in writing there as well. Following a decade of digging in CRM archaeology, he now writes about green energy technology, home energy efficiency, DIY projects, the natural gas industry, and the electrical grid.

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