Circumvent Neutral wire requirement

Configuration
1

Does this make sense to anyone?

My wall switch that controls my Smart Lights does not have a neutral wire coming into the box. I’d like to control my Smart Lights at the wall switch and with automations without leaving the wall switch in the ON (power to the lights) position

If I replace a dumb wall switch with a smart wall switch (zigbee or zwave) without a neutral wire, I think the switch would be hot all the time.

Then, if I configure an automation to turn my Smart Lights On when the top paddle of the Smart Switch is pushed (like turning on a dumb light switch) and Off when the bottom paddle is pushed, this will allow manual on/off control at the wall switch and automations to run regardless of the position of the switch paddle.

Am I thinking about this correctly?

2

I am not sure to understand. I have a couple of these Zwave no-neutral switches and they work the same for me, in automations, as with-neutral switches.

3

There are smart switches that will work without a neutral wire; they are specifically designated as such. The catch is that your load will need to be sufficiently great, such that the light won’t flicker when it’s on. For Z-wave or WiFi devices that requires ~20-50 W, which can be a challenge with LED lighting. It’s much lower (~ 5 W) for Zigbee devices. If your load is smaller than this amount, then there are dummy loads/load bypass/load resistors available. If you wish to keep the same dumb switch (say, you have an old house with an antique switch and wish to preserve its appearance), then you can use a Shelly 1L device (WiFi) or Sonoff miniL2 extreme (Zigbee) mounted behind the dumb switch in the electrical box, provided there’s room. With the Shelly device, if you toggle the switch remotely, then the dumb switch will become out of phase (from the off position you will need to toggle it twice, the first time to bring it back in phase and the second time to actually turn it on–and vice-versa for the opposite state change). The Sonoff addresses this issue differently in that you only need to toggle it once to turn it off or on at the physical switch, regardless of the operation of the virtual switch, but the physical switch will be in the opposite of the usual position every-other-time you use it. Both the Sonoff and Shelly devices may be rated for current draws below your mains circuit, in which case it’s a good idea to add a physical fuse in-line with them.

4

Actually @FortranFour I have many sumb switches like this in my home with a shelly behind each, and it is better to set the switch to “edge” in this case - what that means - if the switch is on and you turn off the light by automation, simply flipping the switch the switch to the off position would turn the actual light on because it was off! Think of it this wasy - when the shelly relay behind the switch is in edge mode, any time you flip the switch, it doesnt matter “on” or “off” - it will simply change the state of the light - turning it off if already on, or turning it on if already off. So, no toggling is even necessary! In my opinion with a simple up/down switch, I don’t care what position it is in, if I am reaching for it I want to change the light - so I flip it and the light changes. Voila! (The same with dumb paddle switches, or any dumb sitch, whatever the case, you get what I mean.)

5

I have an away automation that turns on lights based on history. With my dumb switch, I need to leave it in the On position in order for the automation to control the lights. Or, if I want to control the lights remotely from Lovlace.

Does the Smart Switch need to be in the on position in order for the away automations to work?

6

@Stavros actually it doesn’t matter what position the switch is in if you are using a shelly in edge mode as I had described in my previous post -

1 Like
7

I had heard mention that ‘no neutral’ switches, or maybe dimmers don’t act as repeaters for your ZWave or ZigBee meshes. Not sure how reliable this information was though and as I have nothing to test against I can’t confirm this…… Anyone?

8

Thanks. I did not know about the “edge” setting!

9

You won’t have that problem (needing to keep the dumb switch in the on position) with Shelly (edge setting or not) or Sonoff relays. If you replace the wall switch, then you obviously won’t have that problem either. Despite the indicated wattage said to eliminate light bulb flicker, in practice, I found that some LED bulbs will still flicker when connected with a no-neutral smart switch, regardless of the wattage, requiring that you test out different light bulbs or combinations of bulbs.