Wiring a four-way circuit is easy if you know how to wire a three-way light control. It is just an addition of a 4-way switch in-between the 3-way switches.
A four-way wiring system allows you to control a light fixture from three or more locations. They are useful on stairways or large houses where you want to control a single light from three or more locations.
Diagram of a Four-Way Switch
A four-way switch comprises five screw terminals, 2 traveller terminals, 2 common terminals and one ground terminal.
The terminals are usually coloured. Traveller screws usually have brass colour, common terminals with black colour, and ground or earth terminal with a green screw.
Tools and materials for 4-way switch wiring
- Wire stripper
- 4 in 1 screwdriver
- Utility knife
- Voltage tester
- Electrical tape
- Two 3-way switches
- One 4-way switch
- Non-metallic Romex cable
- Electrical box
For the wiring system to work perfectly, you must install the 4-way switch at the middle of the two 3-ways.
Locate two 3-way switches
But if it is an old house with a wiring system already, look for two 3-way switches.
The switches must not be very close as we only need the travellers for the installation.
Install an electrical box between them.
Using two NM wires, connect the first 3-way switch to the 4-way metal box, do the same to the second 3-way switch and pass the wires to the holes.
Connect the wires and the intermediate switch
Join the two white wires (neutral) together, and also the two copper wires together.
Then connect the remaining two reds and two black wires to the four terminals without minding their colours.
Once you re through, test-run your installation and see if it works perfectly.
Troubleshooting a four-way switch
One of the major causes of power failure is a wrong connection. Make sure you wire the circuit properly by following these steps.
- Connect a four-way switch between two 3-way switches.
- Four-way switches have five terminals. One earth or ground screw, and four travelers terminals. Make sure you connect it properly by following the above diagram.
- For a four-way switch to work properly, the three-way switches must be correctly wired. Make sure that you connect the common terminal of one of the 3-way switches to the power source, and the second common to the hot terminal of the load.
- Make sure that the traveler wires connect to only traveler terminals of the switches. A 4-way switch will only be connected to traveler wires and not hot or neutral wires.
- Make sure the neutral from the source only connects to the neutral terminal of the load.
Once everything is in order, the electrical system will work. If the issue persists, test the switch.
If you have an existing switch that stopped working, it may have worn out or the terminal screw may have loosened. Check the screw with your screwdriver to make sure it is tight.
You can also test the functionality of the switch with a multimeter or continuity tester.
To test a three-way switch, connect one of the multimeter probes to the common terminal of the switch, and the other to the traveller terminal.
Flip the switch toggle to view the meter. If it shows any movement, the switch is still good. Otherwise, the switch may have malfunctioned.
To test a four-way switch, connect one probe to one terminal in a pair and the other probe to the traveller terminal in the other pair. Flip the switch toggle to watch for movement.
Move one probe to the other terminal and test again. Still move the second probe to another terminal for testing. If there is movement, the switch is probably good. If not, change the switch.
How do I Wire a Four-way Light control?
A 4-way switch has two pairs of terminals called T1 and T2. You can wire it by connecting the wires from the traveller terminals of the second 3-way switch to the T1 of the four-way switch, then connect the T2 terminals to the travellers of the first three-way switch.
You can refer to this wiring diagram if you need more insight.
What Colour is the common terminal on a four-way switch?
The common terminal for a four-way switch is usually the black wires.
What is the difference between a 3-way and 4-way light switch?
The difference between the two switches is that a 3-way switch has four terminals, while a four-way light switch has five terminals.
Can I use a 3-way switch as a 4-way switch?
You can use a three-way switch when you want to control a light fixture from two different locations. If it is above two locations, use a four-way switch in between the three-way switches.
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