What Is a 4-Way Switch? How It Works

A variety of switches are used throughout your home for controlling lighting and other items. The common single-pole switch controls one light fixture from one location, a 3-way switch controls a fixture from two locations, and a 4-way switch controls a fixture from at least three different locations, such as in a large room or an open floor plan. Read on to learn about 4-way switches and more about how light switches work.

What Is a 4-Way Switch?

Four-way switches are used to control lighting from three or more locations. Four-way switches are used in combination with 3-way switches.

How a 4-Way Switch Works

When a 4-way switch is bookended by two 3-way switches, it can serve to open a closed electrical pathway or close an open pathway. A 4-way switch has four terminals that provide two sets of toggle positions. When the switch is in the up position, the current can flow through two terminals. In the down position, the current flows through the other two terminals.

Visually, imagine that a 3-way switch connects traveler wires from that switch to one side of the 4-way switch, while the other side is connected to the other 3-way switch, and the 3-way switch is then connected to a light. When connected properly, a simple flip of any of the switches will turn on the light.

Where to Use a 4-Way Switch

Four-way switches can come in handy in large rooms that have many door openings or exits. Each opening from which you can enter or leave a room should have a switch that controls the lighting within that room.

For example, if you have a living room that has three openings you need a 4-way switch to control the lighting in the room. Say the hallway is in the shape of a 'T' and also needs the use of a 4-way switch—by placing and wiring a 3-way switch at two different locations and the 4-way switch at the third location, the lighting can be switched from each location. This is why a 4-way switch is the best solution for lighting control in three or more locations.

3-Way vs. 4-Way Switches

A 3-way switch is very common. These switches are used in combinations of two switches to control lighting from two locations in most circumstances. They may be used in hallways, staircases, and any number of rooms like living rooms, or garages. In the latter case, the lighting may be for the garage itself or the outdoor lighting associated with the garage and front door lighting, being switched in both the home and garage entrance doors. A 4-way switch is not used on its own but is used in addition to a combination of switches, such as a 3-way switch.

Wiring a 4-Way Switch

When wiring a 4-way switch, you need to find out which terminals go together. Use an ohm meter to test the terminals and the toggle positions, or take a quick look at the manufacturer's instructions, which should outline the pairings. Many times, 4-way switches will come with two brass-colored terminal screws and two darker-colored terminal screws. A green ground terminal is also on a 4-way switch.

Each set of terminals will connect to the traveler wires from each of the 3-way switches. When connected properly, you'll be able to turn lights on from either of the 3-way switches or the 4-way switch. If you need to switch lighting from more than three locations, simply add additional 4-way switches between the two 3-way switches.