Three-Way Switches (Two required): Unlike a standard single-pole switch, a three-way switch does not have ON/OFF markings and has four terminals:
Common Terminal (Darker screw): This is where the incoming power (from the source or the load wire going to the light) is connected.
Traveler Terminals (Two lighter-colored screws): These terminals connect to the traveler wires that run between the two three-way switches.
Grounding Screw (Green): Connects to the ground wire (bare copper or green).
Traveler Wires: These are two separate hot wires that run between the two three-way switches.
They provide two alternative pathways for power to flow between the switches, allowing either switch to interrupt or complete the circuit independently. A cable with three insulated wires (typically black, red, and white) plus a ground (often called 14/3 or 12/3) is usually used to connect the two switches
Basic Operation:
The common terminal on the first three-way switch connects to the incoming power (hot wire).
No matter the position of the first switch, the second switch can always be flipped to either complete or break the circuit, thus turning the light ON or OFF from either location.
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