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Shelly Pro EM-50

Shelly Pro EM

Device identification

  • Device name: Shelly Pro EM-50

  • Device model: SPEM-002CEBEU50

  • Device SSID: ShellyProEM50-XXXXXX

Short description

Shelly Pro EM-50 (The Device) is a DIN rail mountable two-channel, single-phase energy meter. Enhanced with all the gen2 firmware flexibility and LAN connectivity, it provides professional integrators with additional options for end-customer solutions. It can work standalone in a local LAN and/or Wi-Fi network, or it can also be operated through cloud home automation services through MQTT, HTTP, and WebSocket. All inbound connections support TLS.

The Device reports accumulated energy as well as instantaneous voltage, current, active, and apparent power per phase in real time. It stores data in non-volatile memory that can be retrieved for a period of up to 60 days in 1-minute intervals.

The Device has a real-time clock to keep the correct time if the connection to an SNTP server is lost.

Shelly Pro EM-50 can be accessed, set up, and monitored remotely by the User, as well as the Device can access and communicate with an automation system, as long as they are in the same network infrastructure.

The Device has an embedded Web Interface which can be used to monitor and control the device, as well as adjust its settings.

The Device has a built-in relay for contactor control.


  • 4 Quadrant measurement

  • DIN rail mounting

  • Current transformer connection

  • External contactor control via built in dry-contact relay

  • No load threshold*

  • Optical pulse indication of energy usage

  • Real-time clock

  • Data logs

  • Accuracy Class B (IEC 62053-21)

  • Photovoltaic ready

* In case the total load for a channel drops below 10 VA the measured power level will be displayed, but no consumed energy will be accumulated to the energy statistics and a No load threshold notification will be displayed in the Device web interface and the mobile application.

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

Shelly Pro EM internal schematics

Device electrical interfaces


  • 2 line inputs on screw terminals: 1 L and 1 N

  • 2 current transformer inputs: IA and IB for current measurement


  • 2 galvanically isolated relay terminals: I and O

Ethernet port

  • 1 RJ45 connector

⚠CAUTION! Plug in or unplug the LAN cable only when the Device is powered off! The LAN cable connector must not be metallic in the parts touched by the user to plug in or unplug the cable.

Addon interface

  • Shelly proprietary serial interface

⚠CAUTION! High voltage on the add-on interface when the Device is powered!


  • Wi-Fi

  • Ethernet

  • Bluetooth

Each connectivity option can be enabled or disabled by the user.

Safety features

  • Overheating protection

Supported load types

  • Resistive (incandescent bulbs, heating devices)

  • Capacitive (LED light drivers, capacitor banks, electronic equipment, motor start capacitors)

  • Inductive (transformers, fans, refrigerators, air-conditioners)

User interface


  • One tactile dome button

    • Press briefly to toggle the state of the built-in relay.

    • Press and hold for 5 sec to activate Device AP.

    • Press and hold for 10 sec to factory reset.


  • LED indication

    • Power: Red light if the power supply is connected.

    • Wi-Fi (varies):

      • Blue light if in AP mode.

      • Red light if in STA mode, and not connected to a Wi-Fi network.

      • Yellow light if in STA mode, and connected to a Wi-Fi network. Not connected to Shelly Cloud or Shelly Cloud disabled.

      • Green light if in STA mode, and connected to a Wi-Fi network and the Shelly Cloud.

      • The LED will be flashing Red/Blue if OTA update is in progress.

    • LAN: Green light if LAN is connected.

    • Out: Red light if the output relay contact is closed.

    • Count: Red light will be flashing when the Device is measuring energy according to settings with frequency dependent on the energy flowing through the measured circuit.





Size (HxWxD):

94x19x69 ±0.5 mm / 3.70x0.75x2.71 ±0.02 in


63 ±1 g / 2.22 ±0.05 oz


DIN rail

Screw terminals max torque:

0.4 Nm / 4.43 lbin

Conductor cross section:

0.5 to 2.5 mm² / 20 to 14 AWG (solid, stranded and bootlace lugs)

Conductor stripped length:

6 to 7 mm / 0.24 to 0.28 in

Shell material:





Ambient temperature:

-20 °C to 40 °C / -5 °F to 105 °F


30 % to 70 % RH

Max. altitude:

2000 m / 6562 ft


Power supply voltage AC:

100 - 260 V, 50/60 Hz

Power supply voltage DC:


Power consumption:

< 3 W

Output circuits ratings

Max switching voltage AC:

240 V

Max switching voltage DC:


Max switching current:

2 A

Sensors, meters

Internal-temperature sensor:


Voltmeter (RMS):

100 - 260 V

Voltmeters accuracy:

±1 %

Ammeters (RMS via CT):

0 - 50 A

Ammeters accuracy:

±1 % (5 - 50 A), ±2 % (0 - 5 A)

Power and energy meters:

  • Active and apparent power

  • Active and apparent energy

  • Power factor

No load threshold:

30 VA per phase

Measurement data storage:

At least 60 days of 1 min data resolution

Data export:

  • CSV for PQ recorded values

  • JSON format export through RPC


RF band:

2400 - 2495 MHz

Max. RF power:

<20 dBm

Wi-Fi protocol:

802.11 b/g/n

Wi-Fi Range:

Up to 30 m / 100 ft indoors and 50 m / 160 ft outdoors
(Depends on local conditions)

Bluetooth Protocol:


Bluetooth Range:

Up to 10 m / 33 ft indoors and 30 m / 100 ft outdoors
(Depends on local conditions)





16 MB

Firmware capabilities

Webhooks (URL actions):

20 with 5 URLs per hook







Basic wiring diagrams

Shelly Pro EM wiring diagram





Load circuit output terminal


Live (110-240 V) cable


Load circuit input terminal


Neutral cable


First channel current transformer input

Current transformers


Second channel current transformer input


First channel current transformer


Live (110-240 V) terminal


Second channel current transformer


Neutral terminal



Components and APIs


Shelly Pro EM-50 multilingual EU declaration of conformity.pdf

Printed user guide

Shelly Pro EM-50 multilingual printed user and safety guide.pdf

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