Wiring for Split Outlet with Z-Wave Switch?

I have holiday (split) outlets under each window facing the front of my home. Top outlet is always hot, while the bottom is controlled at a switch. I replaced this standard switch with an UltraPro Z-Wave (39348), wiring the white to neutral and black to load/line. Unfortunately, it seems the switch is bypassed as the bottom outlets remain hot regardless of switch set to off. Why is this?

Possibly a defective outlet. How are you turning the switched outlet on/off? Physically on the outlet or via an app?

Can you explain this more? If the existing (dumb) switch was wired correctly, the “real” neutral would not be wired to it. When you wire in your new switch, you need 3 separate wires connected to it (plus a bare ground). If the white wire was on the existing switch, it doesn’t seem like it was the neutral. Any pics you can share?

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It’s not a switch, per se. It’s a duplex outlet where the top half is always hot and the bottom half can be switched on/off either manually or via an app. There should be only a line connection, neutral, and ground.

I think I understand what you’re saying, but that doesn’t seem to be what @worked12 is using. The Z-Wave device listed is an in wall switch–not an outlet. My originally understanding is a wall switch controls one outlet of the duplex receptacle. Ed is replacing that switch, right?

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Ok, I went back and re-read it and I think you are correct (plus I looked up the device again and found a proper link). If it’s the case, sounds like he may have wired the line and load together on the same side of the switch. It would explain why the switch is having no effect.

Yes, I’m replacing the old wall switch with a smart switch… to control the split outlets. At the switch j box there are 3 wires, black, white and ground. I wired the white to neutral, black to line/load and ground to green. Prior to hookup, I tested the wires, the black was active and white was neutral. So I have the correct wiring on the new switch. All 8 split outlets behave the same, remain active with the new smart paddle switched off, physically or virtually with smartthings. I recognize this is a ST forum, so I also raised my questions/concerns to the UltraPro manufacturer as well. But I do appreciate your thoughts on this.

If your old switch had the black and white wires connected to it, the white was not a neutral–one would be the “line” and the other the “load” (outlet in your case). You may not have a neutral in the box–if that is the case, I don’t think that smart switch will work without one. If you have any photos of the box wiring with the old or new switch in it (switch pulled out to see how things are wired), that would be very helpful. I have a switch in my front room that controls an outlet, but I have neutrals in my switch box, so it worked fairly simple when I did something similar years ago.

This photo (Option 1) looks like what I’m expecting your old situation to be.

I think you nailed it. The white acts as line in this case and not neutral, which this smart switch requires. I also used this smart switch in other parts of my home, but a neutral was present in those cases.

Here’s a photo of the old switch still attached.


It is very rare that a smart switch gets wired in exactly the same way as the previous dumb switch, because the smart switch has to also power the radio inside— even when the switch is turned off. (So that the radio can hear the next “on“ command from the network.) Consequently it’s important to study the wiring diagrams provided by the smart switch manufacturer and match those, not the wiring from the old switch.

Most commonly smart switches power the radio with a neutral line that may not have been used by the dumb switch at all, and in fact, may not even be in the switchbox. (There are a few smart dimmers which can be powered without a neutral, but those are not appropriate for controlling an outlet.)

It sounds like you’re probably on the right track now, but I just wanted to mention what is likely going on. :thinking:

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Are there other wires (all with wire nuts, usually) in the back of the box?

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No other wires in box. Okay, so I decided to go with this smart switch instead, Enbrighten, no neutral required. Do I wire the black to line/load and the white to the other line/load (see photo). Thank you again, great forum!

That’s a dimmer. Do not use it to control an outlet. The physics are different.

See the user manual for that particular model. In the warnings section, it tells you twice not to use it to control a receptacle (that’s the same as an in wall outlet), because of potential fire hazards.


You need to find an on/off switch that supports up to 15 A and is not a dimmer.

Welp, I might be out of luck then. Haven’t been able to find a on/off smart switch that does not require a neutral. Thanks for the super fast and thorough response. Whatever they’re paying you, they should double it. :slight_smile:

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Thanks, but I’m just another customer. This forum was set up several years ago so that customers could help other customers with ideas and is information. It’s only monitored by SmartThings staff for issues like harassment and spam. So I’m just paying it forward: lots of people here have helped me in the past. :sunglasses:

As far as a no neutral option for controlling a receptacle, I don’t know of one for North American homes. There are a couple that are designed for Asian homes, which have a different electrical system, lower loads, and don’t have the same required safety certifications.

But as others suggested here, there’s definitely a neutral somewhere, the outlet itself needs it. The switch is just a cut out in the line, but that’s not the only thing. So you should be able to put an in wall relay somewhere along the circuit that would work to control the outlet. (Or replace the outlet with a smart outlet)

And then you could replace the existing dumb wall switch with any smart device you want, but take it out of the circuit to the outlet. You could even use a battery powered device there.

That creates a virtual control for the outlet. The switch send a radio message to the hub (or possibly directly to the outlet, depends on the specific models you choose) And then the outlet turns itself on or off.

For example, this outlet

Plus this battery powered wall switch

Would be a good combination. (Just put a blank plate where the existing wall switch is, or a little box cover over it, and then put the battery powered switch there.)

You wouldn’t have to do any wiring for the wall switch and replacing the outlet should be pretty straightforward, but again, follow the wiring diagrams that come with the smart switch, don’t just try to duplicate the existing wiring.

Oh, and take good pictures of the existing wiring before you remove it, including at the screw connections. You can thank me later. :wink:

This is a hard thing to find anymore. LOTS of in-wall switches are “dual purpose” dimmer/switches–so they don’t really have a relay in there (at least that’s how I understand it). The old Homeseer WS-200+ switches were rated this way (15 amps), but they no longer make them. I’m sure there are others.

I was going to suggest exactly what @JDRoberts is suggesting by putting a smart in-wall outlet where your receptacle is located. That would work really well.

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Yes, without a neutral in the box, I would get rid of the switch to control the outlet and replace with the smart outlet that @JDRoberts suggested. I have a couple of dozen of them in my house including one on my front porch that controls the Christmas lights during the season.


I almost forgot… There is one other alternative, which I do use in a couple of places in my own home, which is to put a smart switch cover over the top of the existing manual switch. This is a batterypowered device which physically moves the dumb switch underneath. So you don’t need to change the wiring at all, and you can use the existing dumb outlet, and leave the existing dumb switch in place.

I use the ones from third reality. They are Zigbee devices that work well with smartthings. So that’s another possible approach. :sunglasses:

When it’s actually moving the switch, it’s pretty loud, but not as loud as a garbage disposal. Loud enough to startle the cat. But that’s because it has an actual motor in it that is moving the switch underneath.

It looks a little weird, but it’s still intuitive for guests to use. And you can have it installed and working in five minutes without ever touching a wire.


So just another option.

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Another option if you can find where the wires from the switch tie into the outlet circuit is to install a smart relay at the point. There will be a neutral at that point. They are made by many companies. Since it will be controlling outlets it should have a current rating equal to or greater than the circuit breaker on that circuit.

Your existing dumb switch along with the app and automations would be able to control the outlets.

I would expect to find that interconnection point in the outlet box closest to the switch.

I forgot to mention that I also use a smart outdoor outlet that plugs into an existing outlet. There are several manufacturers but this is the one I’m using. Enbrighten Z-Wave Plug-In Outdoor Smart Switch, Black and there is also a Wi-fi model.

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