Shelly Pro 3EM-3CT63 - 3-phase smart energy meter Wi-Fi + Ethernet (3 x 63A)

Shelly Pro 3EM-3CT63 is a single-phase or three-phase DIN rail-mountable power meter that can operate stand-alone on a local LAN or Wi-Fi network or connect to cloud automation platforms via Modbus, MQTT, HTTP or WebSocket with TLS encryption. Its special combined 3-phase current transformer (CT) is designed to be mounted directly above the circuit breaker. It reports real-time data by phase/channel including voltage, current, active and apparent power and total energy consumed. It is equipped with a built-in real-time clock and stores up to 60 days of data at 1-minute intervals. Settings and monitoring are fully accessible via the built-in web interface. Remark: The device does not include a built-in relay! Load switching is only possible using the module Shelly Pro 3EM Switch Add-on.  

Main features

• Power measurement in 4 quadrants
• DIN rail mounting design
• Compatible with single-phase and three-phase systems
• Contactless current measurement via CT sensors
• Phase sequence detection (optional)
• Inter-channel calibration (min. 500 W load required)
• No-load threshold: 30 VA/channel
• Optical display of consumption
• Real-time clock for accurate logging even in the event of a network outage
• Data storage: 60 days, resolution 1 minute
• External contactor control (requires Switch Add-on)
• Accuracy Class B (IEC 62053-21)
• Ready for photovoltaic systems

 

Connectivity and protocols

• LAN (Ethernet) - 1 × RJ45 connector
• Wi-Fi - 802.11 b/g/n (2.4 GHz)
• Bluetooth 4.2 - for initial configuration
• Supported by Modbus, MQTT, RPC, WebSocket
• All incoming connection protocols protected by TLS encryption

 

Technical specifications

• Dimensions:
  • Shelly Pro 3EM-3CT63: 94 × 19 × 69 mm
  • Shelly 3CT63: 14 × 54 × 26 mm
• Housing: plastic, white
• Operating temperature: -20°C to 40°C
• Humidity: 30 % to 70 % RH
• Power supply: 100-260 VAC 50/60 Hz
• Power consumption: < 3 W
• Protection: type B or C, 16 A, min. breaking capacity 6 kA
• Voltage range: 100-260 V (±1 %)
• Current range: 0-63 A with precision:
  • ±1 % (2-63 A)
  • ±2 % (1-2 A)
  • ±5 % (0-1 A)
• Internal temperature sensor: yes
• Data storage: at least 60 days with 1 minute resolution
• Data export: CSV and JSON (via RPC)

 

Software capabilities

• 20 webhooks, each with up to 5 URLs
• Support for script automation
• MQTT compatible
• Encrypted communication via TLS

 

Monitoring and indicators

• Button:
  • Short press - switch relay state (requires Switch Add-on)
  • 5 seconds - AP mode activation
  • 10 seconds - factory reset
• LED indicators:
  • Red - Power connected
  • Blue - AP mode
  • Yellow - Wi-Fi connected, Shelly Cloud disabled
  • Green - Wi-Fi and Shelly Cloud connection established
  • Flashing red/blue - OTA update in progress

 

Installation notes

• DIN rail mounting (Shelly Pro 3EM module)
• CT sensors are attached directly to the phase conductors (at the circuit breaker)
• Direction of flow: must follow the orientation K→L
• ATTENTION: Only connect/disconnect the LAN cable when the device is switched off!

 

Compatible platforms and integrations

• Shelly Cloud
• Home Assistant
• OpenHAB
• Domoticz
• REST API
• MQTT

 

Examples of use

Industrial electricity distribution:

In industrial environments with complex power distribution systems, a combined three-phase CT mounted above the circuit breaker can effectively measure and monitor currents. This is crucial for optimising consumption and detecting potential problems in real time.  

Commercial buildings and facilities:

In office buildings, where space is often at a premium in electrical cabinets, the compact design of the CT is very useful. Direct mounting to circuit breakers allows efficient use of space and accurate current measurement.  

Motor Control Centres (MCCs):

In production plants with multiple circuit breakers, the combined three-phase CT is the perfect solution to monitor motor currents and help with preventive maintenance.

Data centres:

For data centres, where accurate monitoring of consumption is crucial, CT sensors mounted above circuit breakers allow accurate current measurements of critical equipment.

Renewable energy:

Combined three-phase CT sensors can be used in solar and wind power plants for accurate current measurements directly at circuit breakers in control cabinets.

Monitoring of substations:

In electrical substations, where space is at a premium, mounting CT sensors above circuit breakers is an excellent solution for monitoring the current in individual phases and maintaining grid stability.

Building Management Systems (BMS):

Accurate analysis of current consumption is crucial for smart buildings. Combined CT sensors allow this data to be collected for energy management and responsive load control.

Power quality control:

In environments with critical equipment, such as medical facilities or laboratories, CTs are used to monitor current ripples and detect anomalies that could affect the quality of the power supply.

Electrical cabinet upgrades:

For electrical renovations where space is at a premium, CT combination sensors provide a compact and accurate solution for current measurement.

Smart grids:

In the context of smart grids, real data is key. CTs above circuit breakers provide accurate information for monitoring and optimising the network. In all these use cases, the combined three-phase CT represents a space-efficient and integrated solution for current measurement and contributes to increased efficiency, safety and reliability of electrical systems.