Replace 3-way switches with motion sensors

Question

In my pass-through (i.e. two entryways at opposite ends) laundry room, where people walk in holding laundry baskets with both hands, I'd like to replace the two 3-way switches with motion-sensor switches. It appears to me that this is quite possible to do according to this diagram:

Is this an OK thing to do from the point of view of A. actually working and B. code?

Editing, having received three answers that talk about neutrals. My configuration is Hot->Switch->Switch->Load. My motion sensor switches require a neutral. There are neutrals in each box, at the fixture, and in the 14/3 runners. Of course I'm going to connect all the neutrals together and connect the switches to the neutrals appropriately. I just didn't draw them b/c that's completely straightforward. I only focused on the part that required some thinking, which is how to make the light turn on when either switch is triggered.

Answer 1

Code will be content if the sensors have a manual override to act as a physical switch.

Actually working will depend on the sensor and wiring.

Answer 2

What you have there are not 3-way switches. Those are regular on-off switches. Yes, it would work, assuming that you never need to turn off the load from both switches.

From a code perspective, this would be legal for always-on loads, but not for appliances requiring a disconnect switch.

Answer 3

There are a bunch of ways that 3-way switches can be wired. The key is that most 3-way switches are wired with a 3-wire (ignoring ground) cable between the switches. Two of the wires are travelers. The third wire can be:

• Always hot (a.k.a., line)
• Switched hot (a.k.a., load)
• Neutral

Colors don't mean much. Or rather, if there is a neutral in the cable, it will be white. But white is not always neutral.

So you need to figure out exactly how things are wired. Pictures, not hand-written diagrams, because every detail matters.

With LED lighting in particular, neutral is normally needed at a motion-sensor switch because the switch itself needs power. The classic method of "leak a little through the light" works great with incandescent but fails miserably with LEDs.

If the configuration is truly a sequence of:

• Hot from panel
• Switch 1
• Switch 2
• Light fixture

then the third wire should indeed be neutral and you can wire up motion sensors, smart switches, etc. Except for one catch: they must "understand" three way wiring. In addition, switch 2 is in an odd situation - with traditional 3-way switch wiring it has hot sometimes from one wire and sometimes from another wire (the two travelers). So you really need to research your products to make sure they will do what you need.

Note that some smart/etc. switches can actually wire up with one wire as a signal wire, leaving the other two wires for always hot and neutral. That is, they use the existing wires in an entirely different way.

FYI, an alternative when you need "smart" but not actual motion sensor, is a smart switch system where the remote looks like a regular switch but is actually a battery powered wireless (but not WiFi) remote control. That obviously doesn't require neutral. But it also doesn't work as a motion sensor.