Home » Knowledge Guides » What Is The Blue Wire On A Ceiling Fan? [Detailed Explanation]

What Is The Blue Wire On A Ceiling Fan? [Detailed Explanation]

Many of you may have noticed an unused blue wire when installing a ceiling fan.

However, unlike other appliances that plug into a wall outlet, ceiling fans’ wires are usually not as recognizable. This is especially true with the blue wire being used newer installations.

The blue ceiling fan wire serves another purpose that you may or may not be aware of. It acts as the light switch for your lights. Without connecting a power source to the blue wire on your ceiling fan, you will not be able to control any of the lights from that specific fan.

Here, in this article, we are going to explain in detail what this wire actually does, what it belongs to, and where you can connect it. Keep reading!

blue wire on ceiling fan

The Purpose & Usage of Blue Wire

The blue wire on a ceiling fan is typically used for the light kit.

It is typically connected to the switch’s “load” side, which controls the light. The blue wire may also be used as a secondary hot wire or as a switch leg for the fan itself in some cases.

But it can be a bit confusing when you first take a look at the electrical box. The two-wire cable running from the ceiling fan switch to your light looks very similar to the black two-wire cable.

It is only upon inspection that you will see the blue and white wires along with the gray and black wires.

Types of Ceiling Fan Wires

While most ceiling fans come with black (hot) and white (neutral) wires for easy hookup, there are some fan models that have additional wires, such as red or blue.

  • The black wire is used for the power source only.
  • The white wire is always neutral.
  • The blue wire is sometimes used to control the light kit in three-way switches.
  • While the red wire controls the wall switch in three-way switches.

In a double switch control system, both of them are usually the same color and are either black or blue. The third wire on the ceiling fan can be a variety of colors depending on what it’s used for and how many wires are dedicated to your ceiling fan.

How Does a Ceiling Fan’s Blue Wire Get Into The Fan?

If you’ve never installed a ceiling fan, you might wonder why your electrician should put the blue wire from the fan with the red wire from the ceiling. In the same way, you want to know why he connects the white wire from the fan with the white wire from the ceiling?

But here are two ways you can connect the blue wire to the ceiling:

Single Switch Wiring

Single switch wiring of ceiling fan’s blue wire
Single switch wiring of ceiling fan’s blue wire

The blue wires installed on ceiling fans are connected to both the black ceiling wire and the black fan wire. By connecting the ceiling fan and light kit in this way, the ceiling fan and light kit can be powered by a single light switch.

Make sure the ground wire is connected together. The ground wire is usually green, yellow, or bare copper. Finally, the white wires from the ceiling and fan are connected together.

Dual Switch Wiring

Dual switch wiring of ceiling fan’s blue wire
Dual switch wiring of ceiling fan’s blue wire

If you have a dual switch ceiling fan, your wiring is probably different. The black wire from the ceiling must connect to the black wire from the fan, and the blue wire from the ceiling must connect to the second live wire from your fixture.

To power, your lights, connect either button on your switch to one wire or another. You can also use both wires if you have them coming into your fixture from different directions.

If you are looking for a detailed ceiling fan wiring guide, read out our tutorial.

Also Read: How To Install A Ceiling Fan Without Existing Wiring

Video Credits: E Pros

FAQs – Get Your Answers Here!

Can I connect blue and black wires together?

You can connect the blue and black wires of a ceiling fan together by twisting the blue wire from one end of a single-switch light fixture. Do know that connecting these two wires will turn the light on when you turn on the fan, whereas having separate switches for each will allow you to turn the lights on first and then turn on the fan.

Is a blue wire positive or negative?

The blue wire of the ceiling fan is negative. The black or red wire is positive, and the white wire is neutral.

What color does the blue wire connect to?

The blue wire of the ceiling fan should be connected to the white wire in the box. After all of your wires are connected, use a tester to make sure that each one is correctly connected and that it’s safe to turn on your lights or ceiling fans.

Apart from this, the blue wire connects to the light fixture in your house. The color of a ceiling fan’s wires may vary slightly depending on the manufacturer. In most cases, there are two black wires that connect to a single switch in the room and a white wire that provides power to the motor.

What does the blue wire hook to on a ceiling fan?

The blue wire is a hot wire, and hooks to the black or red wire. It hooks to the hot side of the light kit because if it is not hooked up correctly, the fan will not work.


So why do electricians use blue wire on ceiling fans? It is simply to indicate what they call the blue wire feed. The reason that they use a different colored wire is to keep things sorted out. Using a color code such as white, black or green helps you to identify smaller wires when there are so many wires together.

The blue wire on the ceiling fan connects to the common terminal of the light fixture. This causes the low-speed and high-speed settings to operate normally. You will also use this wire if you are connecting a remote to your ceiling fan.

In addition, if you are connecting multiple lights on one switch, attach the black wire from each light setup to the black wire from the fixture. The other color wires should be attached together for each individual light.