What is the primary function of a three way switch?

The primary function of a three-way switch is to allow the control of a load, such as a light fixture, from two different locations. This is particularly useful in situations like staircases, hallways, or large rooms where you want the convenience of switching the lights on or off from either entry point.

When wiring a three-way switch, it involves two switches that communicate with each other to control a single light or group of lights. This setup is essential for maintaining efficiency and ease of access in lighting design, allowing users to have control over lighting in various areas without needing to walk to one central point to activate or deactivate the lights.

In contrast, choices involving controlling a load at multiple locations or only outdoor lighting do not accurately reflect the specific utility of a three-way switch, which is designed for operation between exactly two locations, not more. Likewise, the option about automatically dimming lights refers to a different type of lighting control and functionality altogether.