Shelly 3EM PRO

Shelly 3EM Pro – DIN Rail 3-Phase Energy Meter for Smart Home & Commercial Monitoring

The Shelly 3EM Pro is a DIN-rail mountable three-phase energy meter. Enhanced with all Gen 2 firmware flexibility and LAN connectivity, it provides professional integrators with robust options for end-customer solutions. It can operate standalone on a local LAN and/or Wi-Fi network, or through cloud home-automation services using MQTT, HTTP, or WebSocket. All inbound connections support TLS encryption.

It reports accumulated energy as well as instantaneous voltage, current, active, and apparent power per phase in real time. Data is stored in non-volatile memory for up to 60 days in 1-minute intervals. The built-in real-time clock maintains accurate time even if SNTP server connection is lost.

The device includes an embedded Web Interface for configuration, monitoring, and control.

 
⚠ Notice: Shelly 3EM Pro does not include a built-in relay. Contactor control is available via the Shelly Pro Addon.

Features

• 4-Quadrant measurement
• DIN-rail mounting
• Multiple connection types
• Current transformer connection
• Phase sequence error detection *
• Channel-to-channel calibration **
• No-load threshold ***
• Optical pulse indication of energy usage
• Real-time clock and data logs
• Accuracy Class B (IEC 62053-21)
• Photovoltaic ready

* Detects incorrect phase sequence using voltage zero crossings.

** Requires ≥ 500 W load per channel for calibration.

*** If load drops below 30 VA per channel, energy accumulation pauses.

Main Applications

• Residential
• Multi-Dwelling Units (apartments, hotels, condos)
• Light commercial (offices, retail, gas stations)
• Agricultural (farms, barns, silos)
• Government / Municipal buildings
• Universities / Colleges

Connectivity & Interfaces

• Inputs: 3 × L + N, 4 × CT inputs (3 phase + Neutral)
• Ethernet Port: RJ45 (LAN) – Plug/unplug only when powered off
• Add-on Interface: Shelly proprietary serial interface
• Connectivity: Wi-Fi | Ethernet | Bluetooth (enabled/disabled by user)

Safety & Supported Loads

• Internal temperature sensing and reporting
• Resistive (loads like heaters, bulbs)
• Capacitive (LED drivers, electronics)
• Inductive (transformers, fans, compressors)

User Interface

• Button:
  • Short press – Toggle attached relay (via Add-on)
  • Hold 5 s – Activate AP mode
  • Hold 10 s – Factory reset
• LED Indicators:
  • Power – Red
  • Wi-Fi – Blue/Red/Yellow/Green (status-based)
  • LAN – Green when connected
  • Count – Red flashing (energy measurement)

Specifications