SmartThings Community

Dimmer with no neutral wire

(Daniel) #43

Got it, so if the radio is on at all times, I assume I will be able to turn the light fixture on or off at any time using the wireless system even if the wall switch is toggled to the off position? Does it make sense?

(Mark) #44

Correct. I have an aeotec micro switch in a ceiling fixture box (hot and neutral to the light in my case) with dumb three way switches attached. The whole thing works great; local switch control, app control, automations etc.

Edit: I’m not sure if the aeotec (or other) dimmers can work in a 3-way setup though. @JDRoberts?


Depends on the specific model. There will be wiring diagrams on the manufacturer’s site. Study these carefully, as there are often very specific limitations if the three-way is being wired with physical traveler wires.

For example, some of the micros allow for dimming from one switch but only on/off from the other.

@RobinWinbourne has done his entire house lighting with Fibaro micros and has done quite a few three-way setups (which in England are called “two-ways”). He can probably link to threads were he has already discussed this in detail.

(Robin) #46

Not sure about alternatives but the Fibaro Dimmer micros usually work well in a 3-way setup (UK 2-way).

It all comes down to your specific wiring layout though… m the micro can go behind the master switch, or sometimes it has to be in the ceiling.

Post a sketch of your existing wiring layout and I can advise further.

(steven clark) #47

Clarification, are you saying the caseta switches always come on at full brightness? Even if ST has the dimming set to a certain level?

(Stephan H.) #48

If you press the top button on the physical wall switch, it always turns on to full brightness. If you use the ST app to turn on the lights, they will resume the last brightness level.

(Smuts) #49

The dimmer level doesn’t stick. SS can turn it on to a set dimmer level.
But the switch itself will turn it all the way. The Pico remotes have a
button in the middle that remembers a setting. They have a battery. I
have a lot of picos mounted on the wall. . . .

(steven clark) #50

Thank you, that’s good to know as I will be setting up a second system in my office and many of the switches are common interupters, no neutral. I will mostly control them from ST using Alexa.

(Adrian) #51

My house in FL was built in 2001. I’m hoping I have neutral at switches. Here are few pics of a few I pulled… can anyone tell me if I have neutral? This entire 2-Wire setup sounds like the anti-Christ of HA. I do not want incandescent bulbs, I want dimmable LEDs only.

I will have to hire electrician to do everything, I know nothing on wiring… I’m about to have ressesced lighting fixtures installed & want full HA without having to buy HUE bulbs… (I ordered hue starter kit, but that’ll be for floor lamps only).

(Adrian) #52

Here is another one:

Am I good?

(Michael) #53

It appears that both boxes have neutrals though the only way to confirm is with a multimeter. The white bundles are typically the neutral.

(Adrian) #54

Ok great, So to confirm that the white wires are neutral, I use a voltage meter… will they be hot? Or no power? What exactly will tell me that they are neutral? Sorry for the newb question, but I’m learning lot of stuff so far.

(Michael) #55

One of the black wires on your switch will be the positive/hot leg. In cases where you have multiple Romex wires coming into a box, the hot wire on the switch is usually a pigtail wire coming from a bundle of black wires while the other wire(s) on the switch do not and are the load to light or a traveler to another switch. Using a multimeter you measure the black wire with one probe and neutral with the other and it should read 120VAC. If you don’t get a reading then keep probe on black wire and touch the other probe to your ground bare copper wire. If you get a reading there then white wires may not be neutral.

Search YouTube on multimeter because there are many videos showing you how to use one. Home Depot has classes every so often as well.

(Adrian) #56

Ok so if I don’t get a reading when testing hot wire with copper, then my white wires are in fact neutral? Hot & white wire should have reading. Think I got it…

Edit- silly question, but when probing the white wires, I have to take wire nut off & touch the bare tip right? It just touching the white sleeve works??

(Robin) #57

Yeah that wont work for a lighting circuit… the lamp will provide resistance and even so, your wiring could be all sorts of configurations.

If you’re relying on images like this I suggest you employ a pro before you break something.

(Adrian) #58

Will be using a pro, just trying to learn along the way. I’m taking what micheal said as the best way to test the neutral.


If you live near a Home Depot, many of them have free classes on how to install a light switch where you can learn a lot, including how to use the tools. They won’t specifically cover networked lights, but since Home Depot does sell the GE brand as well as the Lutron Caseta, the instructor can often get answers for you on those as well. And in any case, you’ll learn more about how to identify circuit branches and will be able to discuss things with your electrician in a much more informed manner.

Separately, If you live in one of their service areas, I highly recommend the Amazon smart switch installation service. This is the one that uses Amazon employees, not third-party contractors. That should be able to install either the Lutron Caseta (which don’t require a neutral) or the GE or linear/go control (which do). They will install up to three switches for $99, which is generally a very good deal. And so far, the ones that I’ve dealt with have already been familiar with regard to the networked devices, which isn’t always true of local electricians.

If you are going to use them, make sure you specify in the appointment booking the exact brand and model of your switches as that will save you time.

I’ve been really pleased with the service. The only problem is it’s not available everywhere, but I think it’s worth considering if you are in one of their service areas.

(Adrian) #60

Not in my area. Are all Zwave switches autimatically detected by ST hub? Compatible

(Robin) #61

No… But you can browse the wiki for officially supported devices and also unofficially supported devices that community members have created device handlers for.


See the following FAQ (this is a clickable link)