I want to retrofit relays into a house where neutral is not available in switch box. I know there are a couple of no-neutral relays, but they have their problems.
I had an idea - is there such a relay I can install in the ceiling lamp and then connect BOTH ends of the rocker to live going to ceiling. When the rocker is flipped there should be a micro poweroff before it is connected again. The relay in the ceiling lamp could recognize that and ensue all the smarts.
Does anybody know of such a relay? Doesn’t matter (pun intended) if zigbee, wifi or something else as long as it works with HA locally.
I think what you’re looking for is something like a SONOFF ZBMini. You can wire it into the box at the ceiling if that’s where the power comes in, and connect two terminals to the wires going to the switch. Flipping the switch will toggle the light, or you can control it from HA.
This also works with a “three way” setup where there are two switches. The wiring diagrams that come with the ZBMini should be pretty clear, once you understand how your switches are wired.
Yep, that’s sonoff basic r4.
Your switches need to have 3 terminal or 2 way switch type. Works for 2/3 way wiring as well even though they don’t advertise it
I’ve used the SONOFF Basic, too. But the ZBMini is tiny. It fits inside the switch box or light fixture. It also uses Zigbee while the Basic uses WiFi.
The Mini also has two switch terminals, in addition to the line in and out terminals. Assuming your power comes in at the light fixture, the diagram below shows how you would wire it. It doesn’t matter whether you have one switch or two (as shown.) You basically put the Mini wherever the power comes in, be that a switch or the light fixture.
Have you seen the Shelly? I’m still experimenting with mine so I’m not sure it quite fits the requirements but I think it sits between live connections and acts in a similar way to the sonoff described above. Works locally over wifi. Comes in regular and mini sizes.
Yeah, it’s quite an underrated feature
You could always request to sonoff to include it their smaller relays lineup.
It’s supported in tasmota/esphome and should work with 90% switches out there.
I’m confused. Where does the power come from, if not from the switch side or the ceiling fixture? Aren’t both the hot and neutral in the same cable from the breaker box?
I’ll try to explain once more:
Neutral goes directly to the ceiling. No permanent neutral in switch box.
Live goes to switch box. From switch to ceiling. No permanent live on ceiling.
No, they are not in the same cable.
Hence the question.
It is quite common in older buildings where I live.
Now I’m also confused, based on the explanations across multiple posts. Could you do a wiring diagram here to illustrate what you have got, and what you are trying to achieve? This is probably one of those “help us so that we can help you” situation.
No it is not the case… ferbulous already answered my original question. I hoped that my idea was original but fortunately (or unfortunately) Sonoff has already manufactured it, albeit in one product only. But I guess it is better than no product at all.
What in my description of the situation trips you off? It is quite simple.
The only places I can install relays and still have physical switch function plus smarts, are:
in the switch box (but needs to be no-neutral relay, that is what they are built for, but they have some issues nowadays with low wattage LED lighting)
on ceiling where I have neutral and SWITCHED live. Which is what I was asking. Which is what Magic Switch Mode of the Basic R4 apparently provides.
I ordered a bunch of R4 and will receive them in a couple of days, so I will flash esphome or tasmota on them and see.
Please let us know how you make out. I’m not really sure where you plan to install one of these in your diagram. I thought I was familiar with wiring, going back to the old knob-and-tube days, but I haven’t run into a fixture wired the way you describe. I’d be very interested in hearing how you solve this one. Thanks!
I always bring neutral to my smart devices, because I can.
I never use Sonoff, because I don’t need to.
But the idea of Magic Mode is brilliant, allow few millisecond switch-off to be sensed while maintaining device powered (from caps?). Much better than other “no-neutral” implementations.
Well… Good for you. In my house built from scratch, I not only brought neutral through the switch box, but also distributed 24V DC around the house for powered sensors, solenoid locks and wall panels, etc which I step down to 12V or 5V with a buck converter as needed.
But this is not one of those cases. It is an apartment in a 300+ year old building with walls 1m thick with electrical wiring ca 100 years old and covered with a lot of plaster. I really, really, REALLY do not want to replaster everything just to get a ceiling lamp smart. Never mind that all such renovations MUST be approved by a local heritage foundation.
If you already have 2-way switches, the “operation” should be minimal with Magic Mode approach.
Another option would be battery operated wireless switches (buttons)…
