1

I have a smart light bulb that needs constant power connected in order to be controlled via my smart home. However, I want my guests to be able to control the light via a switch as well.

I bought a small Sonoff switch that requires no neutral to work, since I do not have neutral in my switch wall boxes.

What I’m thinking is that I can let the light bypass the switch and connect the switch to the Sonoff smart switch, and then using automations, control the light whenever the physical or sonoff switch is triggered.

However, I wanted to verify if the circuit I’m thinking of wiring up is safe to use. The sonoff needs no neutral wire but requires power (Line) in both its Lin and Lout to allow a small amount of current to leak in order for it to power itself.

Will I create a sort circuit by bridging two Line cables together and is this dangerous? Will the sonoff switch work, or the current will just bypass it since there is a path with less resistance? And finally, is this connection safe to do?

The current connection

The proposed circuit for the sonoff switch to create a “detached relay”

nobody
  • 7,701
  • 3
  • 36
  • 47
Lucas P.
  • 113
  • 3

2 Answers2

2

Here's the part you're missing.

Sonoff Wiring Diagram

The Sonoff device must be wired in series with the load just like a regular switch. And just like any other switch, if you bridge the pole with the same line hot wire, nothing will happen because both sides of the switch will always be hot. There would be zero potential between in and out, so the device would be off.

What I’m thinking is that I can let the light bypass the switch

You have to ask yourself why the switch is involved in the first place. If you're going to bypass the switch then it doesn't need to be connected to anything.

If you want to use this Sonoff smart device to control whether the load is on or off then you need to connect the load to the "L Out" wire.

If you want the load to have continuous power, then this Sonoff device is the wrong product.

For a true "bypass" you could get their RFR2 model, hook it up literally anywhere that has hot and neutral, pair it to an RF remote, and voila, you've got a Sonoff device and remote switch that's not connected to any load.

Robert Chapin
  • 8,102
  • 1
  • 15
  • 37
1

That won’t work. You’ve just shorted out the switch. It’d work exactly the same as if the switch weren’t there at all. In fact, the switch won’t even get power to function.

There’s basically no way to both provide constant power to the light and also switch power to the light.

DoxyLover
  • 14,216
  • 2
  • 30
  • 56