As soon as I can I make one. I mean, if there is the switch…then the light…. So i want to put a switch at the bottom of the stairs and at the top of the stairs. The black line wire connects to the common terminal of the first 3- way switch. In the 1st diagram below, a 2- wire NM cable supplies power from the panel to the first switch box.
The circuit to the hallway uses 2 red wires and 1 black wire.
3 Way Switch Wiring Diagram
On the power coming in from the panel, you would connect that black wire to the one black screw. Black common wire is usually wrapped around the two traveler wires on a 3- way switch. What is common in the diagrams above and with any 3-way switch circuit is that the power hot wire coming into the circuit will always go to the common terminal of the first switch. Wiring a 3-Way Switch How to wire a 3-Way switch. Thank you so much. Hot to black screw on switch is all you need to remember. But watch this video.