How To Wire A Bathroom Fan And Light On Separate Switches? (14-Step Guide)

Licensed Inspector Arie Van Tuijl
Licensed Inspector Arie Van Tuijl

πŸ•–Last Updated On May 10, 2022

Are you wondering how to wire a bathroom fan and light to separate switches?

Sometimes you just want the light on a separate switch so you can turn it on without making any sound.

The biggest thing to consider is that you may need to route a new wiring cable from the bathroom fan to the wall switch. 

how to wire a bathroom fan and light on separate switches

This wiring is known as a '12/3' cable and includes two hot wires.

In this HomeInspectorSecrets.com guide, you will discover:

  • Connecting the hots, neutrals, and grounds together
  • Fishing the new 12/3 cable through the ceiling or wall
  • How to connect the new wiring to a double toggle wall switch

Keep reading to learn the supplies that you'll need, and our step-by-step guide on how to do the wiring.

What You Need To Know About Wiring A Double Switch Bathroom Fan And Light

Probably the most important thing to know about wiring a bath fan and light on separate switches is that you will need to run a new wiring cable from the bathroom fan to the existing switch.

If you just had a normal fan with no light or heater, then you just have 12/2 wiring which includes a single hot, a single neutral, and a ground.

But if you want to wire a fan and light to separate switches, you will need two hots running from the bath fan to the wall switch. 12/3 cable includes two hots, one neutral, and one ground.

Use A Licensed Electrician

For most cases, homeowners should call in a licensed electrician to do this job. Your local city or county code will almost certainly require it as well.

There is a risk of electrical shock or even starting a fire if the wiring is done incorrectly.

Electricians have a lot of tricks and methods for geting new wiring cable through a wall or ceiling that the average homeowner may not know.

Read Also >> How To Install A Bathroom Fan On The First Floor?

How To Wire A Bathroom Fan And Light On Separate Switches (1)

Supplies You'll Need To Wire An Exhaust Fan And Light On Separate Switches

  • 12/3 Cable - The bathroom fan needs 12/3 wiring from the housing to the switch in order to for it to use two separate switches. 12/3 wiring includes two hots (black/red), one neutral (white), and one ground (green/copper).
  • Double Toggle Wall Switch - These double switches will have two toggles so you can separately control the light and fan.
  • Wire Nuts - You will need a way to connect the hots, neutrals, and grounds together. You can use the tried and true wire nut. But the easiest way is to use modern quick connects or Wago lever nuts.
  • Fish Tape - A fish tape set will be highly useful if you need to get a new 12/3 cable from the bath fan to the wall switch. Fish tape is flexible and will help you route the wiring through the ceiling or wall.
  • Electrical Tape - You want to use one or two wraps of standard electrical tape around the wall switch to secure the connections.

How To Wire A Bathroom Fan And Light On Separate Switches (13-Step Guide)

  1. Turn Off Power at Panel and Verify It's Off
  2. Remove Old 12/2 Wiring From Bath Fan
  3. Connecting the New Ground to Housing
  4. Connect the Hot Wires At Housing
  5. Connect the Neutrals At Housing
  6. Push Wiring Into Housing And Secure Cover
  7. Route the New 12/3 Cable to the Double Switch
  8. Connect the Grounds At Switch
  9. Connect The Two Neutrals At Switch
  10. Connect Ground Pigtail To Switch Terminal
  11. Connect Power to the Common Terminal
  12. Connect Hot Wires to the Switch Bronze Terminals
  13. Wrap With Electrical Tape
  14. Secure the Double Switch and Re-install Cover Plate

Step 1 – Turn Off Power at Panel and Verify It's Off

As with any wiring job, the first step is to turn off the power at the panel box.

We also recommend that you verify the power is off to the exhaust fan by using a non-contact voltage tester.

A non-contact voltage tester can detect whether there is power by just getting close to the wire or double switch. If there is still power, it will beep or light up (and some do both).

Step 2 – Remove Old 12/2 Wiring From Bath Fan

At the bath fan housing, remove the wiring cover plate, and disconnect the existing 12/2 wiring that goes into the housing.

The ground wire is usually connected to the cover plate grounding terminal.

The two hots (one for the fan and one for the light) will be connected to the old 12/2 cable either through wire nuts or quick connects. Simply disconnect the wiring.

Read Also >> How To Vent A Bathroom Fan Through The Wall?

Step 3 – Connect the New Ground to Housing

Connect the ground from the new 12/3 cable to the bath fan housing.

There will usually be a ground terminal on the wiring cover. Simply hook and crimp the ground wire around the terminal in a clockwise fashion, and then tighten the screw.

Step 4 – Connect the Hot Wires At Housing

Connect the new 12/3 hot wires to the housing.

There will be one hot wire (red or black) to the exhaust fan hot, and then light hot to the second 12/3 hot (red or black).

The light and exhaust fan hot wires from the housing may be red, black, or blue. You will need to connect these wires together using either wire nuts, quick connects, or Wago lever nut.

Step 5 – Connect the Neutrals At Housing

Connect the single neutral wire from the new 12/3 cable to the neutrals coming from the exhaust fan and the light.

These neutrals will have to all be connected together using a wire nut, quick connect, or Wago lever nut.

Step 6 – Push Wiring Into Housing And Secure Cover

Push the wire connections into the bathroom fan housing or wiring compartment.

Re-install the wiring cover plate. Make sure that the wiring is protected from sharp edges by installing a connector or grommet.

Step 7 – Route the New 12/3 Cable to the Double Switch

If the walls are finished, the new 12/3 cable needs to be fished through the ceiling to the wall switch.

If you have attic access, it can help to do it through the attic.

Routing the new 12/3 cable to the wall switch can be the most difficult part of the entire wiring job.

Read Also >> How To Replace A Bathroom Fan Without Attic Access?

Step 8 – Connect the Grounds At Switch

Connect the grounds all together at the wall switch.

There will be one ground coming from the new 12/3 cable from the bath fan; another ground will be from the wall switch box, and the third ground will be from the panel box.

These grounds will all need to be connected using a wire nut, quick connect, or Wago connector. You will also need to create a ground pigtail (short ground wire) that goes from the switch itself to this pigtail.

After connecting the grounds together, push it towards the back of the switch box to get it out of the way.

Step 9 – Connect The Two Neutrals At Switch

Connect the neutral wires to the wall switch box.

There will be one neutral coming from the bathroom fan, and there will be a second neutral coming from the panel box.

You will need to connect these two neutral wires together with a wire nut, quick connect, or Wago lever nut. After connecting them together, push it inside the switch box to get it out of the way.

Step 10 – Connect Ground Pigtail To Switch Terminal

Connect the ground wire from the pigtail (created earlier) to the switch itself.

Simply wrap the ground wire clockwise around the switch ground terminal and crimp it.

And then you can use a screwdriver to tighten the nut.

Step 11 – Connect Power to the Common Terminal

Connect the single power wire (from panel box) to the switch terminal.

The terminal should say 'common' and you will need to connect the power wire to one of these 'common' terminals. Since it is a single circuit, you can connect it to either common terminal.

Read Also >> What Are The Code Requirements For Bathroom Fan Venting?

Step 12 – Connect Hot Wires to the Switch Bronze Terminals

Connect the two hot wires from the exhaust fan and light to the bronze terminals.

These bronze terminals should say 'A1' and 'A2'.

You will need to decide if you want the top switch to power either the bath fan or the light.

Simply wrap around each hot wire on the bronze terminal in a clockwise fashion, and crimp it. And then you can tighten the bronze terminals with a screwdriver.

Step 13 – Wrap With Electrical Tape

Wrap the wall switch once or twice with electrical tape to secure the wiring.

The electrical tape should be around the terminals.

Step 14 – Secure the Double Switch and Re-install Cover Plate

Secure the switch to the switch box using the screws provided.

And then you can snap on the cover plate or it may use a single small screw.

Final Thoughts On Separating Bathroom Fans And Light Switches

The toughest part of bathroom fan wiring to separate switches is usually routing the new wiring cable from the housing to the wall switch.

It can be tricky, and you may need to go into the attic to get the job done.

This part can also be greatly helped if you call in a qualified electrician because they have a lot of tricks at their disposal.

And don't forget there are a lot of different types of wall switches that you can connect to a new bathroom fan and light. There are timer switches, and even switches with humidity sensors built-in.

I hope you enjoyed this guide; please leave a comment or question below.

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