Breaking down the Wiring Diagram: Current enters through the black wire towards the 1 st switch box, attached to the common terminal.; Down position of the 1 st switch means exiting through the red wire and then visiting through traveler terminal into 2 nd switch.; Down position of the 2 nd switch means again exiting but this time through 3 way switch common wire black and enters the light.. The diagrams for 3-way switch wiring I broke down into the following sections (see below): Light after switches. The power source is coming to a light switch first. Light before switches. The power source is coming to light fitting first. The electricity source and light fixture are connected to the same switch.
Includes 3-way switch wiring diagrams for several situations. In This Article: How a 3-Way Switch Works How to Wire 3-Way Switches. A pair of three-way light switches control one or more light fixtures from two switch locations, such as from both ends of a staircase or hallway.. Three-way switch wiring where power connects to first switch.. 1. What is a Three-Way Switch? A three-way switch diagram is a visual representation of the electrical wiring and connections used in a three-way switch system, which allows a single light (or a group of lights) to be controlled from two separate locations.. A three-way switch has:. One common terminal (usually a dark-colored screw). Two traveler terminals (usually brass screws)