motion-sensorswitch
I have an odd situation. I bought a simple occupancy sensor switch but when I opened it up there's an additional red load wire. The existing switch has 3 black wires and the neutral and ground are tied to each other in the box. How do I install the occupancy sensor?
Wiring diagram for Leviton PR180 3-Way Wall Mount Occupancy Sensor.
You have correctly identified supply, and ground.
Now look closely at the legend (labeling) on the switch handle. See where it says "off" and if you flip it, "on"? No, you don't see that? That's because
The dead giveaway is the black screw on the supply being unlike the brass screw also in sight.
The other two wires (the brass screws) are travelers. When you throw the switch, it alternates which one is connected. As such, they are interchangeable, and I like to mark them both with the same color of tape, e.g. Yellow. In my world, two wires in a switch circuit, taped the same odd color, are always 3-way travelers.
There will be another 3-way switch somewhere, also with those same two wire colors going to its traveler terminals.
3-ways are complicated to add dimmers. In some locations Code requires both locations can turn on the light for safety reasons, and that fails if the dimmer at the far location is set to "very dim".
We would need to know more about your circuit and location to give further advice. This won't be the drop-in you were hoping for.
Best Answer
Turn the light switch off, then use a multimeter/voltmeter to check for voltage between the ground and the terminals on the switch. One terminal will read line voltage (120 volts), while the other should read 0 volts.
Once you know what's what, turn off power to the circuit and verify that it's off.
The terminal that reads line voltage, is the line side terminal. If that's the terminal with one wire, attach the single wire to the black wire of the new switch. If it's the terminal with two wires, attach both of those wires to the black wire of the new switch.
Attach the wire(s) from the other terminal (the 0 volt terminal), to the red (load) wire of the new switch.
Connect the white wire from the new switch, in with the other white wires in the box. Connect the green wire from the new switch, in with the other grounds in the box.
Use twist-on wire connectors, or other approved means to make the connections. Make sure you use connectors rated for the number, and size of wires you're connecting.