Smart Switch to control Half-Hot Outlet


First question would be does this work? I would think it does with correct wiring

Which brings me to my second question, what does the wiring look like for this type of switch to contorl the outlet? Spefiically, there is now a red wire involved unlike the overhead lights that I had previously switched out to a smart switch.

Thank you.

(Brent Haag) #2

Not sure what you are wanting to do? Control the switched half of the outlet? If so, then I assume it is controlled with a switch on the wall. Replace that switch with a Zigbee or Z-Wave in wall switch and you’re good. I’ve done it at my house.

(MarkTr) #3

Strictly speaking, you should make sure the switch you’re using is rated for outlet load (typically 15A). I think JD has mentioned that smart switches are normally rated for 10A (sufficient for lighting use).

Edited to add: the GE/Jasco switch I checked is rated to 15A so I don’t know where I got that, but you should still double check the load rating when you choose your switch.

(MarkTr) #4

Typically when you split the outlet, the black wire is the line to the unswitched side and the red wire is “load” on the switch, aka line on the switched side. For your purposes, you would just replicate the connections on your existing switch - incoming line to line on the switch, red wire (out to outlet) to load on the switch - and add the neutral. But see my other comment about load ratings…

(Brent Haag) #5

I guess I’ve always made sure it was rated for 15+ amps, so I’ve can’t say I’ve seen a 10 amp version.

(MarkTr) #6

You’re right, the GE switches are rated for 15A so I’m not sure what I was thinking of - maybe there was a discussion about 20A circuits, or incompatible motors…my bad.

(Brent Haag) #7

No worries…one should always check to make sure the ratings are good, though!

(Mark C) #8

high loads (like heaters) should have a double pole swich. Take a heater apart the on off switch should be double to prevent all the arking issues…


Trying to control an outlet with a smart switch. This outlet is currently top half always hot and bottom is controlled with the switch. Want to replace the switch with a smart switch rather than using two plugs and having the switch always on.


Sounds easy enough! Thanks


Many of the inwall micros are only rated to 10 A, and that’s acceptable under the national electrical code provided they are intended for lighting. Where in most places in the US, in wall outlets have to support at least 15 A.

So you’re probably remembering previous discussions of using micros to control outlets.

UL listed wall switches do commonly support 15 A Precisely so they can be used for outlets as well. But some of the cheap Chinese wall switches which are not UL listed only support up to 10 A. So you do need to read the specs when you want to use a wall switch to control an outlet. :sunglasses:

(MarkTr) #12

That’s exactly it. Thanks!


Just as one example, Some people have asked about using the fibaro double switch, which is an in wall micro, behind an outlet. The Fibaro model is UL listed, but it is only spec’d to 9.5 A, so fine for a light switch but not a 15 A outlet.

(Glen King) #14

Please be careful on this. If you are unsure of what you actually have, get an electrician to check it out.

There are two usual methods of building a switched circuit (this applies to both lights and outlets):

  1. A home run to the switch itself, with that controlling whether any current passes to the light/outlet
  2. A home run to the light/outlet location, with a “switch leg” that controls whether hot gets passed to the light/outlet

In older configurations, the second option will have ONLY the hot! The hot leg comes to the switch; the switch breaks or completes the hot circuit to the fixture or outlet. The switch body is grounded, but the switch has no neutral. (I’ve seen instances where the ground is also nonexistent.) if the installer was sloppy, you’ll even see it done so badly that the wiring works as a “neutral switch” which is hazardous.

Test it, figure out exactly what’s going on with it before you try to change anything.


BTW, if the outlet is not already wired to a switch, yet another option is to replace the outlet with a smart outlet and then use a battery powered switch on the wall. There are some that look like regular wall switches and others that look more like buttons. That way you don’t have to worry about the wiring at all, because the outlet almost certainly has a neutral already. So you just swap out the outlet for a smart outlet and then add the battery powered switch wherever you want it.

The following FAQ shows the various control device options. Some of the listings are for mains powered devices and some are for battery powered, so read carefully to make sure you’re looking at the one you want. If you have any follow-up questions ask them either here or in the discussion thread for that particular device, not in the buttons FAQ itself which is only intended to be one post per device. :sunglasses:

Note: with some devices, the switch will only be able to talk to the outlet if your smartthings hub is also working. With other devices, particularly if both the switch and the outlet are zwave, you may be able to set up direct association which would work even if smartthings is not working. So just something to be aware of.


The outlet is already tied to the switch so I’d rather use that if possible. Going to get into it tonight.


What do you mean by Home run?

(Glen King) #18

Wire run to it’s ‘home’: the breaker panel. You might have a few fixtures or outlets on a run, but ultimately that run goes back to the breaker panel. In the construction industry, they call that the “home run”.

Btw, that’s why the concept of a switch leg exists. If you run the wire for a series of fixtures in a string of offices, you run the home run straight to the first fixture, then from there to the second in line, etc. And then you run a “switch leg” for each individual room. It’s far better and easier (more direct) than trying to run the home run to each switch.


Thank you for all your help everyone. Turns out I was making it much more difficult than it needed to be. Ended up replacing the switch with the smart switch using the configuration that was already there adding in the neutral. And it worked. Now I think I’m going to change out the is leviton I bought with the GE ones I previously purchased for the sole reason of being able to control the LED light on it since it is in the master bed.

Thanks again!