Sonoff 4CHPRO R3 to replace Impulse Switches in Electrical Cabinet

Hello,

I am about to install a modified Sonoff 4CHPRO R3 but, as my electricity knowledge is basic, I wanted to share it with you to receive advice/criticism

(I will also ask questions in real life but I thought it could be interesting for some of you).

What I have today :

  • Inwall push buttons
  • When you push the button, it makes the contact and send 24V AC to an Impulse Switch (teleruptor ? not sure of the correct english translation)
  • Then the light is either on or off

What I tried :

  • Shelly1 in the electrical cabinet : Kind of work but a lot of cable and wago connectors for just one switch and the wifi reception was not always great when the cabinet was closed.
  • Sonoff 4ProCH with Tasmota and SwitchMode13 on 0.1s : it works great to trigger the impulse switch as a complementary push button but I don’t know the light status(I played with esp32 and light detector to know if the lamp is on but it’s not a good solution :))
  • Remove the impulse switch, replace it by Wago’s, put Zigbee lamps and replace the impulse switch by zigbee switch. Works greatof course but requires a lot work and not easy revert to former situation.Also need to be sure about the Zigbee groups to have it continue working without Deconz up.

This project :

  • Sonoff 4CHPROR3 with Tasmota
  • I soldered extension cable to the 4 physical button
  • Replace 4 impulse switches by one Sonoff in the electrical cabinet.
  • I intend to bind 1 phase through Wago’s and only put the second one trhough the Sonoff’s relay.



Questions :

  • I noticed that all my inwall switch have a color wire + 1 common white wire connected to the 24V AC transfo in the electrical cabinet.
  • I took the risk and connected the color cable and the white to the Sonoff and it worked. But, I assume I am sending 24V to the ESP8266 pin when I press the inwall switch. Is this ok/safe ?
  • Do you seen any electrical/hazard risk with what I intend to do ?

Thank you very much for any advice/criticism !

Tibus