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pwsabm
Feb 9, 2014, 07:24 AM
I had an electrician come in to replace a 3 way switch at my home with a z-wave 3 way switch. He told me that the z-wave 3 way can not be installed because on my home 3-way wiring the load goes to the light fixture instead of going to the switch.
My research, and the little work I did, wiring my basement long time ago, indicated the load always going to the first switch of a 3 way circuit. Did the electrician trace the wiring wrong? Or is it possible to wire a 3-way he way he indicate? If h s correct how do I install the z-wave?

Thank you

hkstroud
Feb 9, 2014, 08:33 AM
My research, and the little work I did, wiring my basement long time ago, indicated the load always going to the first switch of a 3 way circuit.

That is incorrect. There is five ways a set of 3-way switches can be wired. Power can be fed to the switch first or power can be fed to the fixture first.

It appears that the Z-wave switch requires a neutral. If power is fed to the fixture there is no neutral at the switch.

Since the neutral is required at one switch only, and one of the travelers is used as a signal wire only, you may be able to use the z-wave switches if the travelers pass through the ceiling box. Note that I said may, I would have to sketch it out.

pwsabm
Feb 9, 2014, 08:46 AM
Thank you Hkstroud.
The z-wave requires constant power in order to communicate with the Z-wave system wirelessly. That is why the load needs to be at the first switch. The traveler will then be used to feed power to the second Z-wave switch in that circuit.
Unless I can get constant power to the first switch I guess I can not install the Z-wave switches. Again, thank you for the quick response.

hkstroud
Feb 9, 2014, 12:08 PM
Disagree, I think it can be done. What is needed is a neutral at the 45610

The 45610 requires a neutral but does not require a hot.
The 45612 requires a constant hot but does not require a neutral.
See the schematic below.

If the travelers pass through the ceiling box see the drawing to the right.

Hot of the power in cable (black) is connected to the red going to the 45612, providing a constant hot. The red is used to return the switched power to the fixture. The white is the signal wire to the ceiling box. It is connected to the red to take the signal to the 45610.
The neutral of the power in cable (white) is connected to the neutral (white) to the fixture and to the white to the 45610. The black of the cable to the 45610 would be unused.

If the travelers do not pass through the ceiling box and go through the walls see the drawing below.

The neutral of the power in cable is connected to the white of the fixture and to the white going to the 45610. That gives you a neutral at the 45610. The black of the power in cable is connected to the red to the 45610. There it is connected to the red to the 45612. That gives a constant hot at the 45612. The black of the 45612 is the switched hot back to the 45610 where it is connected to the black back to the ceiling fixture.

The white between the 45610 and the 45612 is the signal wire.


I do not show grounds. They are available at all points but are not part of the circuity, and make the drawings messy.

Check it out and tell me if I am wrong.

hkstroud
Feb 9, 2014, 12:25 PM
Reposting drawings, hoping they will come out larger.

pwsabm
Feb 9, 2014, 06:59 PM
Thank you Hkstroud

I am glad you disagreed with me and took the time to offer a solution.
I will trace the wires next weekend and see if I can wire the z-wave as you recommended. I will let you know how it turns out.

Again thank you for taking the time and offering a solution.

hkstroud
Feb 10, 2014, 12:37 AM
OOPS

I screw up, big time, will not work if travelers go through walls. The cable between the fixture and the switch will be a 2-wire cable. My drawing shows a 3-wire cable.

Sorry.

Will work if travelers go through the ceiling fixture like in first diagram.