Replacing 3-way switch in 4-way circuit with an occupancy switch - not working correctly [duplicate]

Question

I'm trying to replace one of the 3-way switches in a 4-way switch circuit with a 3-way occupancy sensor.

Here's my current wiring for the occupancy sensor:

And here's the current wiring for the other 3-way switch

I haven't touched the 4-way switch.

Before I changed any wiring, the black screw on both 3-way switches was connected to the black wire.

Here is the current behavior of the circuit:

When occupancy sensor is OFF:

• 4-way switch does not function
• If the 4-way switch is in the OFF position:
  • 3-way switch does nothing
• If the 4-way switch is in the ON position:
  • 3-way switch works, but only if I switch it slowly. If I switch rapidly, it only works every other time the switch changes.

When occupancy sensor is ON:

• 3-way switch works properly
• When the 4-way switch is switched, the lights flicker off while the switch is in between positions.

Any thoughts on what I've screwed up with my wiring?

Answer 1

You generally have 3 conductors in a 3/4-way switch loop, and you can't misuse ground as a conductor. That leaves Only two ways to do it (short of a relay and low-voltage wiring):

Smart switches in the auxiliary locations

Obtain smart switches designed to be "remotes" for the main motion sensor and interact with it electronically, either using 1 wire as a data line, or wireless via power-line signaling or radio.

Very lucky topology

This can only work, if

• supply power comes in to the light, the switches are all one spur, and the motion sensor is in the first box.
• supply power comes into the same switch box as the spur to the light, and the sensor is in that box.
• the essential interconnections are in conduit, and you can pull more wires.

Otherwise you'll have a spot where you need 4 wires, and you only have 3 in the walls.

Your sensor needs three wires coming in: always-hot, switched-hot from the switch, and neutral for the light's current return. The sensor doesn't need neutral, but the light does, so inevitably neutral must come back this way.

http://www.lutron.com/TechnicalDocumentLibrary/369488.pdf

It does not support a 3-way switch. It supports a plain switch which switches between 'open' and always-hot or switched-hot. If it is placed in one position and the one other position was a 3-way switch, then they have you rewire the 3-way to be a plain switch.

Since you have two remaining positions with manual switches, those two positions must together emulate the behavior of a plain 1-way switch. They way you do that is the classical 3-way circuit. The 4-way switch needs to be swapped out for a 3-way. Which you happen to have spare. However, if supply to the light also travels the switch wires, you'll need 4 wires in that segment:

• always-hot for the smart switch
• messenger 1
• messenger 2
• neutral to return current from the light

This is one more than a traditional n-way, installed with the usual 14/3, and you can't retrofit a consuctor.

This does work if your topology is just right: the two remaining physical switches are on a spur. In that case you won't need to carry lighting power (i.e. The neutral) between switches and you'll have enough wires.