So my house's wiring is a hot mess (Built 1940). I have a light switch that is at the end of the circuit and a Zen 21 switch. Is there any way to get the Zen 21 to work?
Does that mean you have no neutral wires in the switch box?
I've got black, white, and ground coming in. But there is not a 2nd set of wires going out of the box.
That's uncommon for sure. Is it part of a 3 way? If not they must have the common or hot going straight to the light and using the switch to break the circuit.
Does the white wire have any black tape on it? One wire is likely just a hot wire into the switch and the other is the load wire to the fixture. Most folks will mark the white wire in some way to mark that its not a neutral, and the black tape is usually close by. Your best bet is to get a no-neutral dimmer.
This is more common than you might think... especially in older homes. Most 3 way switches will have a common wire and two travelers. I'm not aware of any way to wire a 3-way with only two wires.
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Was there a "normal" switch there before?
My guess it comes off another a light fixture and the circuit to turn on the light. When correctly wired, the black will be power and the white will run to the light. But things are not always wired correctly.
I believe you will need a dimmer capable of "no neutral" operation. When the dimmer is "OFF" it is really on a very little bit. This allows the dimmer to remain powered when the light is OFF.
You won't see ON/OFF switches that work w/o neutral because most use relays to turn power OFF leaving no path to power the radio.
Don't feel too bad about your 1940's house wiring. Until a few years ago this arrangement was common.
edit:
@dylan.c I didn't mean to step on your post but I hadn't read all the way through the thread before posting.
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@dylan.c and @JohnRob are probably right re: the function of each wire. But I would just reinforce that in theory, an electrician (or whoever installed the wires however many years ago) could have used any colors they wanted. AFAIK that’s never been standardized by electrical codes in the US.
The only way to know for sure would be to put a multimeter on each wire. But from your description, it doesn’t sound like it’s possible to use a smart switch that requires a neutral wire. There are a few that will work without neutral wires though. You could also consider installing a module in the ceiling fixture, where there would have to be both hot and neutral wires.
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Thanks everyone for the advise and feedback.
My home was built in 1969 (no aluminum wiring). There are no neutrals in any of the boxes. I changed the bulbs in the fixtures to either ZigBee or Z-Wave. So far, the WAF is good. Not sure what you are trying to accomplish, but for me with no neutral, smart bulbs were the answer.
I have one fixture (the above sink kitchen light) that is for some reason wired this way. This would have been wrong or at the very least unusual to do it this way during the era my home was built, so not sure how it happened.
In any case, I use a Lutron Caseta dimmer here and it works terrific in this situation.
If you look up "switch loop" on Google and click the pictures tab, you probably will find a diagram that matches what you have. You probably will have to pull the light fixture to verify the wiring there just to be sure.
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BTW
If you do go the dimmer w/o neutral route, you don't have to worry which wire is "line" (aka hot) and which is "neutral".
Because the voltage is AC (key word is "alternating") it does not matter to the dimmer which is connect to the line and neutral.
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The Lutron dimmers are both black pigtails with no calling out one or the other as hot. That is one reason they are a good choice in this situation, you can hardly mess up.
Thanks again everyone. To summarize, my options are to either use a Dimmer switch or mount a relay in the junction box with the light.
Those are the two I can think of.
If you use a relay (dimmer OR switch) in the junction box, you can use a Pico remote or something like the Zooz Zen34 remote button at the wall, and in multiple other places throughout the room without using wires.
Any Lutron product will also require purchase of a PRO hub. They are not zigbee or zwave.
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Most smart switches and dimmers need a neutral wire.
There are a few that don’t, including some z-wave models.
Some, but not all, Lutron caseta dimmers and switches work without a neutral wire as well.
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For clarity’s sake, Lutron caseta dimmers and switches will need a caseta pro bridge.
There are other Lutron product lines that integrate with Hubitat in addition to caseta. RadioRA 2, for example. The RadioRA 2 main repeater is the integration point for Hubitat in that product line.
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my parents have wiring like this. the main feed is in the light fixture, and they broke the hot to send to the switch. neither wire is neutral
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This is indeed very common. I have a house built in the 80’s and one of my switches is setup that way - the hot goes down to a switch, with the hot and neutral in the light receptacle.
An Inovelli Red dimmer is also a good option as it can function with no neutral.
Yes I agree.
Other thoughts:
- Most dimmers can be setup to only be full ON or full OFF.
- If you put a small dimmer in the light fixture something like this.*** you have two options.
- Use the two wires going to your end wires to control the dimmer vs the S inputs.
- Use the two wires to provide power to a smart switch or dimmer and setup direct association ** of the dimmer control to the mini dimmer in the light fixture.
*** There maybe better devices than the one linked. I did not verify this dimmer supports association.
Association is a direct link from the switch to the mini dimmer. The signal does not have to go through the hub. Usually there is no or minimal delay in operation.
