Sonoff 4CH PRO (R3) WiFi + RF smart relay switch with 4 channels and dry contact support

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Sonoff 4CH PRO R3 is Sonoff’s premium 4-channel smart switch relay, released in July 2020. Equipped with both WiFi and 433MHz RF receiver, it is both remotely contollable via Internet and smartphone, and locally by RF remote controller. Supports momentary switching, dry contact (voltage free) switching and interlock mode to support AC and DC motor operations.

SKU: SON-REL-4CHP-R3 Category:
EAN: 6920075775815


Sonoff 4CH PRO has extended functionality compared to the standard Sonoff 4-channel smart switch relay, and “R3” is the 2020 July new product version with additional features compared to previous Sonoff 4CH Pro R2 version.

It is a WiFi-equipped smart relay switch, to control 4 electric circuits / gangs. The smart relay is remotely controllable via Internet and iOS (Apple) or Android smartphone App, and you can also set scheduled turning ON / OFF. Share remote control in the App with your family. Ideal solution to smart control home appliances, that don’t need to operate all the time and can be turned ON / OFF periodically (e.g. aquarium air pump). By using the smart switch relay you can remotely turn ON any of your appliances even before you are at home and you can conveniently set a scheduled turn OFF to save energy and cost.

SONOFF 4CH Pro R3 are is 4-gang DIY Wi-Fi Smart Switch designed to give you the ability to integrate smart control into your existing home to enable a smart home. It has 4 gangs / electric circuits that can be used to control lights, wall plugs, AC and DC motors at the same time. 4CH PRO R3 is designed with an RF control function, so it can be also switched locally via Sonoff RF remote controllers.

The smart relay supports 3 working modes including self-locking, interlock and inching mode. The new improvement on 4CHPROR3 compared with 4CHPROR2 is for users to set these 3 working modes on eWeLink APP instead of the hardware itself, easier to operate. So you can enable self-locking mode to turn on/off 4 connected devices separately, interlock mode to turn on 1 connected device every time and turn off the rest of devices simultaneously and inching mode to turn on 1 connected device and then make it turn off automatically after a given time (0.5 – 3600s). For the device away from the switch, you can create a moveable space in virtue of a DIN rail to make them be connected. Simply activate devices through your voice when the switch works with Alexa and Google Home smart assistant.

The product is widely used to remotely control (typically 24V DC) gate or garage door openings, as well as 24V AC irrigation systems, as well as, manage 230V AC light and wall plugs.


4CH Pro R3 version compared with 4CH Pro R2 previous version :

  • The 433.92 MHz RF capability has been extended: new R3 relay version can be now paired with multiple (up to 4) RF remote controllers (R2 relay could only be paired with one remote controller)
  • Momentary / Auto-off / Inching switch mode can be now set in the eWelink app (between 0,5-3600 sec), not with physical jumper settings like in R2 relay version (1-16 sec).
  • Interlock / standard (self-lock) mode can also be set in the app, while in R2 relay version it was set by hardware jumper settings
  • More stable cable fixing with screws
  • Higher max. performance is provided in R3 relay version: 10A/2200W/gang, 40A/8800W/in total


Product features:

  • Remote ON / OFF – Anytime, anywhere, from now on you can turn all your appliances on and off remotely.
  • Supports 4 channels – 4 relays in 1, controling 4 circuits with 1 device
  • Momentary switching mode and auto-off is available (0,5 sec – 1 hour)
  • Interlock mode is available to support AC and DC motor control
  • NO / NC scenarios are both available
  • Zero voltage / dry contact switch is also available
  • Fits to DIN-rail
  • Controling the 4 channels independently
  • Physical on/off buttons
  • Mobil App – free iOS és Android mobil App: eWeLink
  • Sync status – Check actual relay status (turned ON or OFF) with the mobile App
  • Timer – Various timer functions: single time, scheduled turn on/off, countdown/timer, loop.
  • Share control – Control the device together with your family
  • Scene – Turn ON / OFF a gang of devices with one tap
  • Smart scene – Triggered ON/OFF by temp, hum or other environmental sensors
  • Compatibility – Works perfectly with Amazon Alexa, Google Assistant, IFTTT and Google Nest


Modes of operation:

Sonoff 4CH Pro smart switch relay operation mode details:

Voltage input for relay operations:

230V AC input:

DC input:

Relay wiring:

For 230V AC plugs and lights:

For AC motors:

For DC motors:

Additional information

Weight 0.35 kg
Dimensions 14.5 × 9 × 4 cm
Product type

smart relay



Number of electric gangs controlled


Momentary switch (Inching)


Physical switch


DIN rail compatible




433MHz RF remote controllable

yes (remote control not included)

Remotely controllable via internet


Voice control

Amazon Alexa and Google Assistant compatible

Power meter


Schedulers, timers

yes (single, schedule, timer/countdown, loop)

Smartphone app

yes, free app: eWeLink (Android, iOS)


Amazon Echo, Echo Dot, Amazon Tap, Google Home, Google Nest, IFTTT


100-240V AC 50/60Hz, or 9-23V DC

Maximum power output

10A/2200W/Gang, 40A/8800W/Total

WiFi wireless standard

802.11 b/g/n (2.4GHz)

WiFi security mechanism


Operating temperature range


Supported humidity range

5%-95% RH

Brand / Manufacturer