A light switch that has 2 switches is commonly called a double pole switch or a 3 way switch. This type of light switch allows control of a light fixture from 2 different locations, like at the top and bottom of a staircase, or at each entrance to a large room.
Page Contents
How Does a Double Pole Light Switch Work?
A double pole or 3 way light switch works by having 3 contacts – a common contact and 2 travelers. The common contact is connected to the hot wire from the circuit breaker or fuse box. The 2 traveler contacts switch this hot wire between 2 screw terminals on the side of the switch.
In one switch, the common contact is connected to terminal 1 and one traveler is connected to terminal 2. In the other switch, the common contact is connected to terminal 2 and the other traveler is connected to terminal 1. The light fixture is connected to the common terminal on one of the switches.
Flipping either switch breaks or completes the circuit, turning the light off and on. The switches work independently, so you can turn the light on or off from either location.
Types of Double Pole Light Switches
There are a few types of double pole light switches:
- Standard toggle switch – A basic mechanical switch with a lever you flip up or down.
- Decorator switch – A more stylish mechanical switch with a paddle or rocker you press.
- Smart switch – An electronic switch controlled via smartphone, voice assistant, schedule, motion sensor, etc.
- Dimmer switch – Allows you to vary the brightness of the light.
- Timer switch – Turns the light on or off automatically on a schedule.
Double Pole Switch Wiring
Proper wiring is essential for a double pole switch to work correctly. Here are the basic wiring steps:
- Turn off power at the circuit breaker.
- Run 14/2 or 12/2 NM cable between the 2 switch boxes.
- Run 14/2 or 12/2 NM cable from the light to one switch box.
- Connect the common wire to the common terminal on each switch.
- Connect one traveler wire to terminal 1 on the first switch.
- Connect the other traveler wire to terminal 2 on the second switch.
- Connect the light hot wire to the common terminal on either switch.
- Connect the neutral wires in both switch boxes.
- Ground all of the switch boxes.
- Turn the power back on and test the switches.
Always follow local electrical codes and use copper NM cable rated for in-wall use. Hire an electrician if you are uncomfortable working with house wiring.
Double Pole Switch Uses
Some common uses for double pole light switches include:
- Staircases – Allows control from top and bottom.
- Large rooms – Control at two entrances.
- Long hallways – Turn on/off from both ends.
- Outdoor lighting – Control from indoors and outdoors.
- Garages – Switch at house door and interior garage door.
- Basements – Control from top and bottom of stairs.
Double pole switches provide flexibility and convenience for controlling lights from multiple locations. They are easy to wire as part of new construction or remodeling projects.
3-Way vs 4-Way Light Switches
3-way switches have 2 switches controlling 1 light. 4-way switches allow control from 3 or more locations by adding intermediate 4-way switches between the two 3-way switches.
A 4-way switch has 5 terminals. The two traveler wires from one 3-way switch connect to the two brass terminals. The two traveler wires to the other 3-way connect to the other two brass terminals. The common terminal is connected to the power source.
Add a 4-way switch anywhere along the circuit between the two 3-ways. This allows you to have multi-location control of the light.
Troubleshooting Double Pole Light Switches
If you’re having issues with a double pole switch, here are some things to check:
- Ensure wires are connected to the common terminal on both switches
- Verify traveler wires go to opposite terminals (1 & 2) on each switch
- Confirm the load wire is connected to the common on one switch
- Check for loose wire connections
- Test for power at both switches
- Inspect wires for damage or shorts
- Replace any non-functional switches
Use a multimeter to check for power at each switch location. If there is no power at one switch, inspect connections, wires, and switches until you isolate the problem.
Light Switch Safety Tips
Here are some important safety tips when working with double pole light switches:
- Turn off power at the breaker before working
- Use caution when working in metal boxes
- Connect copper wires securely
- Don’t overtighten terminal screws
- Use wire connectors approved for switching circuits
- Install decorator style switches with spacers
- Use switches rated for the circuit voltage
- Mount switches properly in electrical boxes
Taking basic safety precautions will help prevent electrical shorts, shocks, fires, and other hazards when installing or replacing double pole light switches.
Frequently Asked Questions
Why do you need a double pole switch?
A double pole switch is needed to control a light fixture from two separate locations. The switch has two poles or sets of contacts to allow interrupting the hot wire from either location to turn the light on and off.
Can I use a dimmer switch instead?
Yes, you can use a double pole dimmer switch to allow dimming control of a light from two locations. Make sure it is compatible with the lighting and rated for the circuit.
Do I need a neutral wire for a smart switch?
Most smart switches require a neutral wire in the switch box to operate. However some models are designed for boxes without neutrals. Check the requirements of the specific switch.
How do I wire a double pole GFCI receptacle?
For a double pole GFCI outlet, you wire line hot 1, line hot 2, line neutral, and load neutral to the line terminals. Then connect the load hot 1, load hot 2, and load neutral wires to the load terminals.
What gauge wire is required for a double pole switch?
For 15 and 20 amp circuits, use 14 gauge or larger NM cable for double pole switch wiring. For a 30 amp circuit, use 12 gauge wire. Follow local electrical codes for required wire size.
Conclusion
Double pole light switches allow convenient control of lighting from two locations. They work by switching the hot wire from two separate poles. Proper wiring, with a common and two traveler wires, is essential for correct operation. Double pole switches have many useful applications in staircases, large rooms, hallways, outdoors, basements, garages, and more. Following basic safety procedures and troubleshooting techniques will allow you to successfully install or replace these switches.