
Device identification
- 
Device name: Shelly Pro 3EM Switch Add-on
 
Short description
Shelly Pro 3EM Switch Add-on (the Device) is a galvanically isolated switch that extends the features of the Shelly Pro 3EM series of devices allowing the control of contactors or other electrical appliances.
Main applications
- 
Residential
 - 
MDU (Multi Dwelling Units - apartments, condominiums, hotels, etc.)
 - 
Light commercial (small office buildings, small retail/restaurant/gas station, etc.)
 - 
Industrial (factories, power plants, water processing, refineries, etc.)
 - 
Agricultural (farms, barns, silos, etc.)
 - 
Government/municipal
 - 
University/college
 
Simplified internal schematics

Device electrical interfaces
Inputs
- 
1 load circuit input I
 
Outputs
- 
1 load circuit output O
 
Add-on interface
- 
Shelly proprietary serial interface
 

?CAUTION! High voltage on the add-on interface when the Device is powered!
Safety features
- 
Internal temperature sensing and reporting
 
Supported load types
- 
Resistive (incandescent bulbs, small heating devices)
 - 
Capacitive (LED light drivers, capacitor banks, electronic equipment)
 - 
Inductive (contactors, transformers, fans, refrigerators)
 
User interface
Outputs
- 
LED indication
- 
Power: Red light if the power supply is connected.
 - 
Out: Red light if the output relay contact is closed.
 
 - 
 
Specifications
| 
 Type  | 
 Value  | 
|---|---|
| 
 Physical  | 
|
| 
 Size (HxWxD):  | 
 94x19x69 ±0.5 mm / 3.70x0.75x2.71 ±0.02 in  | 
| 
 Weight:  | 
 20 ±1 g / 0.70 ±0.05 oz  | 
| 
 Mounting:  | 
 DIN rail, attached to a Shelly Pro 3EM  | 
| 
 Screw terminals max torque:  | 
 0.4 Nm / 4.43 lbin  | 
| 
 Conductor cross section:  | 
 0.5 to 2.5 mm? / 20 to 14 AWG (solid, stranded and bootlace lugs)  | 
| 
 Conductor stripped length:  | 
 6 to 7 mm / 0.24 to 0.28 in  | 
| 
 Shell material:  | 
 Plastic  | 
| 
 Color:  | 
 White  | 
| 
 Environmental  | 
|
| 
 Ambient temperature:  | 
 -20 °C to 40 °C / -5 °F to 105 °F  | 
| 
 Humidity:  | 
 30 % to 70 % RH  | 
| 
 Max. altitude:  | 
 2000 m / 6562 ft  | 
| 
 Electrical  | 
|
| 
 Power supply voltage AC:  | 
 N/A  | 
| 
 Power supply voltage DC:  | 
 3.3 V and 12 V (from Shelly Pro 3EM device)  | 
| 
 Power consumption:  | 
 < 1 W  | 
| 
 Sensors, meters  | 
|
| 
 Internal-temperature sensor:  | 
 Yes  | 
| 
 Output circuits ratings  | 
|
| 
 Max switching voltage AC:  | 
 240 V  | 
| 
 Max switching voltage DC:  | 
 30 V  | 
| 
 Max switching current AC:  | 
 2 A  | 
| 
 Max switching current DC:  | 
 2 A  | 
Basic wiring diagrams
| 
 
 ![]() 
 Resistive load  | 
![]() 
 Inductive load and RC snubber  | 
Legend
| 
 Terminals  | 
 Wires  | 
||
|---|---|---|---|
| 
 O  | 
 Load circuit output terminal  | 
 L  | 
 Live (110-240 V) wire  | 
| 
 I  | 
 Load circuit input terminal  | 
 N  | 
 Neutral wire  | 
Components and APIs
Compliance
Shelly Pro 3EM Switch Add-on multilingual EU declaration of conformity.pdf
Printed user guide
Shelly Pro 3EM Switch Add-on multilingual printed user and safety guide.pdf
      
      
