Old wiring and Z-wave switched: No Neutral. Any options?

I have newer heard of 3 way switches not having 3 wires, it cant work with 2.

Okay, so you do have three wires… now the fun is just trying to figure out which is hot or load, and which are the traveler wires. You might be able to tell my looking at the back of the existing switches. Hopefully they’ll be labeled, though not always… especially if they are so old. It might also be that the travelers are on one side and the hot/load is the lone wire on the other side. Or you might just have to have an electrical look at 'em.

FWIW, I’ve experimented with my GE Jasco switches and hooked up wires wrong many times. Obviously things won’t work when done wrong, but I also haven’t ruined any switches… after fixing the wires they have always worked. I can’t guarantee that you won’t wreak things if you hook them up wrong.


Great explanation of the reason why the switches need neutral, and why the CFL and LED bulbs are not useful with the other switches.

This is a frustrating issue I’m having as well.

Can I ask, have you (or anyone else) tried using LED bulbs in these non-neutral switches?

I’d ideally like to get a switch that (1) does not require a neutral, (2) dims, and (3) uses LED bulbs. As far as I can tell this combination does not exist in the world anywhere. Anyone have a workaround?

With LED being so big now, I don’t see how I could install switches that don’t use them. So my fallback would be a switch that does not require a neutral and supports LED.

Any help appreciated. Thx!

Basically, no. Incandescents can have a tiny amount of current without actually turning on. CFL and LED will turn on with any current (or flicker anyway). I think a solution might be to use connected bulbs instead of switches and use a minimote as a switch for it (or have it automated with a motion sensor). I haven’t tried the latter myself so YMMV.

You have two main options if you are in the US. (If you are in the U.K., let us know.) and two more possibilities, depending on the exact use cases.

  1. use smart bulbs. That works very well for many people. The Hue white light bulbs typically cost $15 each. Once you decide to use smart bulbs, there are several options for what to use for switches with them. See the following topic:
  1. use a micro relay that goes in the wall but put it someplace on the circuit where there is a neutral. There has to be one someplace. It’s typically at the light fixture itself. This works very well for many people. The aeotech relays are on the official “works with smartthings” list. Lots of people use them.


  1. use Lutron Caseta switches. Lutron has many lighting patents, they use different engineering than everyone else. And their switches can be used without a neutral wire to control dimmable dumb LEDs. The problem is they don’t integrate directly with SmartThings. However, they do have an IFT TT channel, which gives you an indirect integration. This means they will work well with their own light switch. They will work just fine when you put them on a time schedule. Where you may have an issue is if you want a smartthings-controlled motion sensor to trigger the Lutron switch to come on. Then the lag maybe too much depending on how much lag you get from IFTTT. So this option will work well for some people, but not for others. It just depends on your specific use cases.

  2. the fourth option which works in some houses is to have an electrician “Fish up” a neutral from elsewhere in the wall, usually at an outlet. This can be done in many houses, although not all. It won’t work in cement walls.


Wow! Awesome response. Thanks for this info.

Some options here I had not considered. The microswitches in with the light fixture seem like a solid option.

Some of the other options like the smart bulbs always bugged me, because they are either a bunch more complicated or don’t work intuitively for guests or relatives. I really only like the solutions that allow complete control from ST but also old fashioned wall switches In the usual way. Sounds like those micro switches are a good bet for instances where I don’t have a neutral at the wall switch.

Thanks again.

The micros definitely give you more options, so they’re certainly worth considering.

You might also take a look at the thread on switches for smart bulbs. There are several ways to get around the problem of someone turning them off. For example, there’s a new battery operated zwave smart switch that fits over the top of the existing wall switch. You leave the existing wall switch always on to power the smart bulbs, but you still have an intuitive switch that can be used at the wall.

So lots of choices, it just depends what works best for you. :sunglasses:

One problem. Looks like according to the web information linked, the micro dimmer and micro switch cannot control LED bulbs “with a trailing edge”? Is that accurate and what means it? (Are the standard Cree and Philips bulbs I’m buying at Home Depot going to present a problem?)

"With LED lights.

For the control of LED lights with a trailing edge, Z-Wave dimming products are not suitable."

Well, I just switched ALL of my lights to LED and now one of my LEDs is always on (VERY dim) - THANKS for the explanation!

Watch out for the hue bulbs. The last I heard if they lose power, they don’t come back on in their last state, they come on full white light and Phillips is citing legal reasons for not changing it. So when my kids turn off the lights at night at the switch, the lights are of course now unreachable, and when they do come back to life, they are bright white and on, even if their last state was off.

The good news for me is that most of the three way switches I have to deal with are in multi gang boxes with other traditional light switches so there is a bundle of ground wires in the back I can use. In the one place where I have a three way switch in a single gang box, there is a closet with a light switch right behind it on the same wall. So I’m just gonna move that switch outside the closet and put both switches in a 2 gang box where I will have a ground. Fishing the neutral up from another box, just doesn’t seem safe to me. 10 years from now when you sell your house someone is gonna find that ground wire and have no idea what is going on.

And one other comment to the folks back up in the comments that are dealing with knob and tube, and old cloth wrapped wire. It may still be working, but there are inherent problems with it and you really should look at upgrading your wiring to current standards when you can. And look at it this way, if you upgrade your wiring, you can make sure you have a ground in all of your switch boxes.

Smart bulbs are intended to always have power available (see the user guide), but you can solve the switch issue in many different ways. :sunglasses::level_slider::bulb:

See the following FAQ (this is a clickable link)

My point is the Hue bulbs come back on after a power outage, or after a traditional switch is thrown in a set state that you as the homeowner can’t control. I have a couple of sylvania lights coming in that are supposed to have a user configurable default state so that they don’t come on in a state that you don’t expect. If I had that feature, I wouldn’t mind using a standard switch so much because once the bulb comes back on, it’s easy enough to change it’s state to what I want in just a couple of seconds.
Whoever comes up with an easily implementable solution to the issue of three way switches without neutrals, that supports LED bulbs is gonna have a nice income stream for a while I think.

The problem is that using the standard switch and frequently cutting power to the smart bulbs is likely to shorten the lifespan of the smart bulbs all together. They’re just not designed to be used that way. The simplest solution these days is one of the smart switch covers that fits over the existing switch but doesn’t actually cut power to the bulb. But then you do have to pay for one more device.

Whoever comes up with an easily implementable solution to the issue of three way switches without neutrals, that supports LED bulbs is gonna have a nice income stream for a while I think.

Lutron did it. :wink: And patented it. :bulb: And indeed makes good revenue from it. :chart_with_upwards_trend:

Unfortunately, unlike wink and staples connect, SmartThings doesn’t have an official Lutron integration.

You can get indirect integration because both Lutron and smartthings have an IFTTT channel/service , and it works well for many use cases, but it does add some additional lag which means it doesn’t really work well with Lutron lights triggered by SmartThings motion sensors. But for time based automations or turning things off, it works fine. :sunglasses:

I was under the impression that Lutron’s solution doesn’t work with LED or CFL bulbs.

Nope, works just fine with dumb dimmable LEDs and CFL’s.

You may be thinking of the older GE Zwave switches which didn’t require a neutral. Those only worked with incandescents.

But Lutron is an engineering company and went to work and just a couple of years ago introduced the Caseta line specifically to address the issue of LEDs without neutral wires.

These are the ones that they’ve tested, but most work fine.



Are there any outlets on that line? If so, then (if I understand this right) anything plugged in with a ground will present a potential shock hazard as someone touching it can provide a path to earth. Also, if there is a GFCI earlier in the path, it will probably trip as the switch will look like a voltage leak to the GFCI. At least, I think these are the main worries.

The missing neutral problem has been a big pain for me. Someone ran some of the switches in my house using 3 wire cable, but didn’t bother to connect the neutrals. That’s a easy fix. Just irritating. Sloppy. I have other switch loops run with 2 wire cable. These are hopeless. . . .

I bought some z wave relays that I’m going to install in some of the light fixtures.

That’s what I ran into as well, but mine is a new house. I understand why they didn’t run the neutrals to the switch, it’s just a pain because what we are doing is more advanced than the standard builder wires for today. The best option I found and in my book it’s still not really safe, is to pigtail to an outlet or switch near by. From what I understand the CGFI is typically off the line side so it shouldn’t be a problem. As for the neutral, it shouldn’t be a problem electrically. Note though, I’m saying Neutral meaning the path back to the panel intended to carry current vs the Ground which I am calling the bare wire that is a safety path back to the panel, which is not intended to carry current except in a problem situation.

And that’s interesting. In the circuit box the neutrals and grounds are all tied together. And I have often wondered just what might happen should a ground be used as a neutral… Not that I’m advocating this.

So the reasons this should not be done are well explained here:

Which is old news and correct. But a Z-Wave device is going to require an extremely small amount of current and I wonder just how unsafe it would be.