Switches are used to turn lights and outlets on and off. These basic yet essential elements of your home’s electrical system may look the same on the outside, but there are actually four different styles of switches commonly used in residential settings.
In your home you may find:
- Single pole switches
- Double pole switches
- Three-way switches
- Four-way switches
Each of these electrical switches functions in a unique way and is wired into your home for a specific purpose. Understanding the design and function of each switch will help in the planning phase of renovations and remodelling projects. Be sure to budget for the price differences in each type of switch and keep the installation considerations in mind.
Single Pole Electrical Switches
This is the most common switch in your home. You’ll find single pole switches in bedrooms, bathrooms and living areas. They are wired into light fixtures and outlets and may also be used to power up outdoor items like a hot tub heater or landscape lighting. The most important distinction to remember is that single pole is used to provide one source of turning a fixture/outlet on and off.
Single pole switches are marked with “on” and “off” locations, unlike the three-way and four-way options. The switch needs to be installed so that the on and off labels are displayed properly and logically. You’ll find two terminals in a single pole switch and most often the green screws or ground terminal are left out. This type of switch is wired into the black or hot wire.
Double Pole Switches
Designed in a similar way to the single pole switch, the double pole switch has four terminals instead of the two found on single pole models. This allows for 240 volts of power to pass through the switch. Use the double pole design to provide one source of turning a 240 volt appliance, fixture or circuit on and off.
You’ll find a green screw or ground terminal on a double pole switch. This allows for proper grounding throughout the system. Double pole switches are found less often in residential buildings, but they do have a specific purpose. These electrical items cost more than the single design and take longer to install, due to the multiple terminals and grounding.
Three-Way Switches
This type of switch is always used in pairs. Three-way electrical applications occur when a room has more than one entrance or a light fixture, outlet or circuit requires two switch locations. You’ll often find these at the top and bottom of stairways. Both switches turn the same fixtures on and off, working together in a three-way connection.
Because the positions of on and off vary while the switches are being used, three-way models are not marked with the labels found on a single or double pole design.
Wiring up a three-way connection can be tricky. You’ll find three terminals on this type of switch. The most important terminal is for the hot wire, generally the darkest terminal. It is often marked with COM or “common” on the switch, but when replacing an older three-way switch it’s essential to mark the common/hot wire before removing the old switch. The other two terminals are wired with travelers or leads, which do not need to be attached to a specific terminal. A green screw or ground terminal is also found on this type of switch.
Three-way switches are always used in pairs throughout your home. Replacement can be a tricky job and if you’re unsure about how to wire in the connection, contact an experienced electrician and have them complete this job quickly and professionally. Single pole and double pole switches cannot be used to replace a three-way switch.
Four-Way Switches
Four-way switches are used in conjunction with a pair of three-way switches. They act as the third, fourth, fifth (on so on) switch between two ends of the connection. Four-way switches look much like a double pole and are fitted with four terminals. They do not have the “on” and “off” labels found on the double pole since they are always used within a three-way application loop.
For instance, if your home has a light fixture that requires eight different switch locations you would need to wire in two three-way switches and six four-way switches. The four-way models are used to connect the leads or travelers. The COM terminal is missing, since the hot wire is not connected to this switch.
Four-way and three-way switches are expensive and require a fair amount of time to install. Three-way switches require the most amount of time, although the placement and connection of four-way models also present a challenge to DIY enthusiasts. Often hiring an electrician is the wise thing to do when designing this type of electrical system.
Various Appearances
In the past switches were widely available in the toggle design. This remains the most affordable option, although rocker and decora styles are also available in a variety of colors and widths. All of the different appearances are designed to fit into a standard switch box.
The different switch styles look the same when covered with a faceplate. One of the easiest ways to tell the difference between a single pole and a three-way or four-way switch is to look for the “on” and “off” labels. If you cannot see the words that particular switch may be a three-way design. Replacement of this style is much more complicated, so be sure of the design before you attempt a change on your own.
Most homes contain each of the four switch styles. Single pole switches are most common, while double pole switches are used to turn 240 circuits on and off. Three-way switches are installed at each end of a connection where two or more switches are wired into the same fixture. And four-way switches are installed in between that pair to supply extra switches. Replacement times and price tags vary between each switch style. Electrical work can be complicated and most homeowners are wise to contact their local electrician during renovations and remodeling projects.