two three way occupancy sensors

[stevo wis]

Hi,
I have an L shaped hallway where i would like to put occupancy sensors. There is currently one 3-way switch at each end, but they cant see each other. All of the three way sensors i have seen replace one of the switches and require a change in wiring to the other. Is there a way that I can wire two sensors, one at each end, so that the lights go on if either end is occupied?
thanks,
Stevo

[Wade Lippman]

I just went through this and couldn't find any. You need power at both switches and that requires running a wire from the one with the line in to the second one. Unless you can do that, you are out of luck.

Presumably there is a way to do it with wifi switches, but I didn't want to go there.

[Frank Pratt]

Lutron makes an extensive line of occupancy sensors, dimmers & wireless (not wifi) switches. I think they have a wireless ceiling mount IR/US (can see around corners) sensor that communicates with one of their switch/receiver units. You'll have to check on their website to see if it will do what you need.

Wattstopper also specializes in occupancy sensors & may have something.

[James Biddle]

I’ve got 3-way motion sensors at the top and bottom of my stairs. Either will turn the lights on and both must have no motion for the time out period.

[Paul F Franklin]

I installed two Lutron MS-OPS5M switches with occupancy sensors on an L shaped stairwell, one at the top and one at the bottom. With the L shape, a single sensor wouldn't do the job. I've attached a wiring sketch. I think they will work in almost any 3 way switch setup without running new wiring. The switches require no connection to the neutral.
The wiring is different than a standard three way setup, but no extra wires should be required, it's just a matter of wiring correctly in the boxes. My sketch doesn't show the grounds.

3wayOS001.jpg

[stevo wis]

Paul, this looks like what I need. It looks to get power to each switch as Wade mentioned above.
Thanks so much for the diagram. I think i will wire this on a bench and then put it into the walls. I actually have a couple locations that need this, as lights are too often left on.
Thanks again,
Stevo

[stevo wis]

James, do you have any idea how it was wired?
thanks,
Steve

[Frank Pratt]

A little off topic, but related. The new Canadian Electrical Code that just came into effect requires that all switches have a neutral conductor available in the switch box. That's gonna make it much easier for everyone from the manufacturers to electricians to homeowners when it comes to lighting control choices. This is something that should have been adopted decades ago. Don't know what the NEC requires.

[Paul F Franklin]

The NEC requires this too (neutral in switch boxes; don't recall which version adopted it, but it's been quite a few years.

[stevo wis]

Frank and Paul,
I am naive about this. How does the presence of a neutral wire simplify the lighting choices?
thanks,
Stevo

[Frank Pratt]

Having a neutral makes it easier to power the electronics that are in dimmers, time switches, occupancy sensors, smart switches & other automation devices.

[Paul F Franklin]

Things like the items Frank mentioned require a little bit of current to operate the internal electronics. When there's no neutral available, there are only two ways to get a little current flow; one is to allow it to flow to the load (light fixture) or to allow it to flow to the ground connection. Neither is a good solution. The former can cause problems with LED lamps glowing slightly even when "off". And allowing current to flow into ground is a safety issue and a code violation. Having a neutral at the switch solves the issue because the operating current can flow to the neutral, which is what it is designed to handle.

[Frank Pratt]

What Paul said. Much better explanation.

[stevo wis]

Thank you Everybody!!

[Wade Lippman]

I installed two Lutron MS-OPS5M switches with occupancy sensors on an L shaped stairwell, one at the top and one at the bottom. With the L shape, a single sensor wouldn't do the job. I've attached a wiring sketch. I think they will work in almost any 3 way switch setup without running new wiring. The switches require no connection to the neutral.
The wiring is different than a standard three way setup, but no extra wires should be required, it's just a matter of wiring correctly in the boxes. My sketch doesn't show the grounds.

3wayOS001.jpg

In order to function, a motion sensor needs a complete circuit; without power it can't do anything. I suspect this setup sends current through the ground; which is a code violation.

Am I wrong?