2

I have a light fixture that can be turned on/off from two locations. One location is on a Lutron occupancy sensor switch, and the second is a standard flip switch.

However when I flip the standard switch to the off position then the motion sensor switch no longer activates. So I would like to wire the flip switch box to stay in the on position permanently, remove the switch and install a covered plate to close off that location or if someone knows a better way please let me know.

My objective is to prevent anyone from accidentally turning off the flip switch which disables the motion sensor switch. Hope I explained that well.

1
  • Is replacing the occupancy sensor with a different model that does support 3-way switching an option? Also, what precise model of sensor do you have? Yours may support this already with an appropriate remote switch fitted/wired Mar 9, 2023 at 3:10

1 Answer 1

3

If you want the three-way switch to still function as such, you may find the MS-B102 (pdf) or the OPS or VPS series devices (pdf) useful (as pointed out by ThreePhaseEel in the comments). If you aren't able or willing to replace the motion sensor, though, read on.*

Since the circuit was originally a two-switch light circuit, it's almost certainly wired as a three-way switch. A three-way switch is usually wired with a 3-conductor (plus ground) cable, as in the following image (ground not shown):

Image of a three-way light circuit.

(image originally from Wikipedia and modified by me)

As you can see, no matter what state the switches are in, switching on of the two switches will change the state of the light bulb, either making or breaking the circuit.

It's most likely someone replaced one of the original manual switches with your Lutron device, leaving either the red or the black wire hanging loose (hopefully protected with a wire nut, but you never know).

I would like to wire the flip switch box to stay in the on position permanently, remove the switch and install a covered plate to close off that location

This is likely the only option for safely disabling the manual switch. You will need to disconnect the power at the breaker panel, pull the manual switch from its housing, and inspect its switch box. In that box you should find one 3-conductor cable (if North America: red, black, white)** from the other switch, and one two-conductor cable (black, white) going downstream to the light fixture.

First, determine which of the two hot conductors (red or black) was left dangling in the motion sensor switch box. (I'll assume it's the "red" one for the rest of this post.) Cap the other end of that "red" wire inside the manual switch's box. (Both ends of the "red" conductor should now be capped with wire nuts and it's now just an unused piece of copper in the walls.) The other motion sensor hot conductor ("black") will need to be wire-nutted to the black wire from the 2-conductor cable. The two white neutral conductors should already be tied together in the box. Check as well if the box is grounded (bare-copper ground tied to each other and to the box if metal).

In summary: "red" to nothing, "black" to black with a nut, white to white with a second nut.

Once you've safely tied everything together, close the box with a blank cover plate and restore the power to the circuit.


* and if you do want to replace your motion sensor, note that the wiring will be completely different from what is described here. Follow the instructions that come with the new sensor instead.

** if not in North America, the neutral conductor is likely blue, and the two hots will be brown and black. The grounding wire may be bare copper, green, or green/yellow striped.

2
  • 1
    The switch the OP wants is the MS-B102 or the MS-OPS6M2x-DV -- both of those support 3-way applications with a simple mechanical switch as the remote Mar 9, 2023 at 4:25
  • Thanks for the heads up! I've edited the post to include links to these models.
    – Matt S
    Mar 9, 2023 at 4:34

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.

Not the answer you're looking for? Browse other questions tagged or ask your own question.