There are a few different approaches that electricians can take when they carry out home wiring.
They might wire for convenience – making everything work as simply as possible.
Alternatively, they might wire for customization – ensuring you have complete control over the devices in your home from multiple switch points.
Unfortunately, a third approach exists – when they wire your home in whatever way takes the least time, as long as it passes code – even if it’s poorly thought-out.
When it comes to bathroom wiring, many people will wire both a bathroom fan and light onto a single switch, taking the convenience approach – assuming that people will always want the light and fan to switch on simultaneously.
But what if you don’t? How do you wire the fan and light onto separate switches?
You’ll need an independent circuit for the fan and light. Ensure the hot wire is split to run to both switches and devices separately. To split existing circuits, you’ll need to access the junction box with both wiring and run the wiring for one device to a new switch.
To help you get the right approach for your home, let’s explore:
- Whether you should separate the bathroom fan and light
- How to wire them independently
- How to wire a double switch for the fan and light
How To Wire A Bathroom Fan And Light Independently
Before explaining how to wire the bathroom fan and light independently, it’s helpful to first explain how a bathroom switch is wired when the fan and light are wired together.
Because if you’re starting from scratch with a brand new bathroom, then it’s straightforward to run separate wires to two different switches and then wire these to the light and fan.
But most people aren’t building new rooms – they’re looking to make changes to an existing room.
So, a hot wire will be running from the circuit breaker to the bathroom switch. It will be a waterproof switch inside the bathroom, or it’ll be located just outside the bathroom door.
From the switch, a wire will run to the ceiling, where there will be a junction box – a secure box that holds all the wire connections for nearby devices.
And inside this junction box, the wiring will be split, likely using wire nuts.
The hot wire will split off to both the light and the fan from the same wire nut connector, and the neutral wires and ground wires will also be wired into matching wire nuts.
Before starting the re-wiring, you just need to work out which wire is for which device.
You only need to separate the live wires – so don’t worry about the neutral or ground ones. Leave those wired as they are.
If you can’t work out which is which, just switch off the power, disconnect a wire, and turn the power back on, then flick the switch – only the light or the fan should work.
Turn off the power and label the wires, so you know. This will work for both the hot and neutral wires.
With that done, you can work on wiring them independently. There are three parts to the job:
- Running a new wire to the new switch
- Running a new cable from the new switch to the junction box
- Connecting the new cable to the device.
Running a new wire to the new switch
You’ll need to connect your new switch to the power, so once you’ve cut the hole for the switch, you’ll need to run a cable from that wire to the old switch.
Then, you can connect the matching wires to the original switch junction box.
Provided you connect the black hot wire to the same wire nut as is powering the hot terminal on the original switch, this will give power to both controls, independent of each other.
Connect the neutral wires and ground wires in the same way.
Running the wire from the old switch to the new one should be easy if the switches are close together.
If you have a reason to have the switches spaced apart, you’ll need to use wire rods (Amazon) to fish the wire through the wall without completely demolishing it.
Running a cable from the new switch to the junction box
Then, the biggest job is running the cable from the new switch to the junction box. You want to avoid destroying the wall just to run the new cable.
You will likely need wire rods for this, and you’ll need to have the light fixture and extractor fan removed, so you can see inside the ceiling.
Push the wire up the wall cavity using wire rods, and if you can fit inside the ceiling cavity with the fan removed, you should be able to see the wire and pull it through to the junction box.
It might be easier with a second person, one to push it up the wall using rods and one to retrieve it once it reaches the ceiling cavity.
Connecting everything together
You’re ready to re-wire everything when the new cable reaches the junction box.
Disconnect the existing live connections, wire the old cable from the old switch to the light or fan (your choice), and the new cable to the other.
With that done, you should have two independent circuits, each controlled by a separate switch.
Test that they work by turning the power back on, and then get the fixtures for the fan and light re-installed.
Should I Separate A Bath Fan From Light?
Consider whether you need to wire the exhaust fan and light separately.
And there are a few reasons that you may wish to.
They’re often wired together because of the assumption that you’ll want both to run at the same time.
But the primary purpose of an exhaust fan is to remove steam from the room when you’re taking a shower or bath – and people often use a bathroom for other purposes.
Plus, many people have large windows in their bathroom, and while they’re often frosted for privacy, they can still let a lot of light into the room.
With that in mind, you might only sometimes need the fan and the light to switch on.
If you’re taking a bath or shower during the day, or at least late in the morning, you might not need the light switched on.
But you’ll still want the fan to be running. Otherwise, you could risk damaging your bathroom by encouraging mold to grow.
If you’re visiting the bathroom for another purpose, you might not want or need the fan on, especially if you’re staying at night and the bathroom is adjacent to the bedroom of a light sleeper.
Plus, you could save energy by only switching on the device you need.
Neither a bathroom light nor exhaust fan tends to draw a lot of power – fans usually draw between 5 and 40 watts, and lights between 6 and 60 depending on the bulb type – but the bathroom is used a lot, especially in large households.
As power costs rise, saving electricity in any way can contribute to larger annual savings.
For these reasons, it often makes sense to separate the switches. But you may need to train yourself (and your family) to switch both on when required.
Mainly a fan – this one is easily forgotten.
People remember to turn on a light when it’s dark, but they may need to remember to turn on the fan before their shower or bath.
It’s something to bear before you separate them – how easy will it be to make sure everyone remembers to use the fan switch to keep your bathroom safe and mold-free?
How To Wire A Double Switch For Fan And Light
Wiring a double switch for the fan and light doesn’t really make any difference – because a double switch is just two adjacent switches in the same terminal.
It makes your job slightly more manageable, not so much from a wiring perspective but from a practicality viewpoint – you don’t need to cut your wall for a second switch.
Depending on your choice of switch, you may need to make the existing switch hole slightly larger.
You’ll still need to wire the hot separately into both hot terminals on the double switch and then run separate wires from the load terminals to the light and fan separately.
The only extra consideration is ensuring you wire the switch terminals correctly – check the switch for markings to indicate which terminals are hot and which are load.
If you wire it incorrectly, then your switches won’t work.
Wiring a bathroom fan and light separately is your choice, but if you do it, it’ll be much less work to use a double switch (and it might encourage you to remember to use both switches instead of forgetting the fan).
The only tricky bit will be running new cable behind the walls, but using wire rods if necessary, it should be manageable without needing to demolish and replaster (or re-tile) the wall.
Do you have your fan and light on the same switch or different ones? Are you now considering making a change?