How to Wire a 4-Way Switch, Showing all Schematic Diagrams.

In our last lesson, we learned how to wire a 3-way light switch. Today in our electrical wiring tutorial, we shall look at the 4-way switch wiring.

Wiring a four-way switch is easy if you are familiar with three-way switch wiring. It is just an addition of a 4-way switch in-between the 3-way switches.

Multi-way switching allows you to control light fixtures from three or more locations. They are useful on a stairway to control the light from both ends and halfway.

Diagram of a 4-way switch

A four-way switch comprises five terminal screws including 2 traveler 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 green screw.

Materials required to wire a four-way light switch

  • Two 3-way switches
  • One 4-way switch
  • Non-metallic Romex cable
  • Switch box
  • Bulb

Tools required for the installation

They include:

  • Wire stripper
  • 4 in 1 screwdriver
  • Plier
  • Utility knife
  • Voltage tester
  • Electrical tape

Note: Before working on any electrical system, make sure you power off your circuit breaker and also wear your protective glove to prevent electric shock and other hazards.

4-way wiring diagram

Wiring a 4-way light is easy for electricians. But for non-electrical workers, it seems to be hard. To understand everything about four-way switch wiring, first, learn how to wire a single pole light switch and three-way switch wiring.

Once you understand the wiring procedures, you will know it is very easy.

From the above wiring diagram, the power source (black wire) from the supply moves straight and connects to the common terminal of the first 3-way switch. The traveler terminal with red and black wire connects to the T1 terminal of the four-way switch.

It then connects to T2 of the same switch before connecting to the traveler terminals of the second 3-way switch and the light bulb.

You can also see the earthing wires (yellow wires) duly connected to the ground terminals.

The black electrical tape on the white wire shows that the wire is a hot wire and not neutral.

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.

Testing switches

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 traveler 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 traveler 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.

Frequently Asked Questions

How do I Wire a Four way Light switch?

A 4-way switch has two pairs of terminals called T1 and T2. You can wire it by connecting the wires from the traveler terminals of the second 3-way switch to the T1 of the four-way switch, then connect the T2 terminals to the travelers 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 of a four-way switch is usually black, and the travelers in brass colour.

What is the difference between a 3-way and 4-way 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 three different locations. If it is above three locations, use a four-way switch in between the three-way switches.

Related articles

Guide on how to wire a doorbell

How to wire a single, and two-way switch

How to wire a three-way light switch.