Shelly Pro 3EM energy cost meter AC 120 A 50-60 Hz

Shelly Pro 3EM is a DIN-rail mountable three-phase energy meter for AC systems, designed to monitor energy consumption and instantaneous electrical parameters. It supports up to 120 A per phase and operates at 50–60 Hz. The device reports accumulated energy and real-time voltage, current, and power factor per phase, stores up to 60 days of on-device historical data with 1-minute resolution, and offers Wi‑Fi, LAN and Bluetooth connectivity along with MODBUS and MQTT support for integration into professional installations.

Advantages

The Shelly Pro 3EM provides 1% active energy measurement accuracy (Class B) and supports 4-quadrant measurement of imported and exported active energy for capacitive and inductive loads. It offers simultaneous Ethernet and Wi‑Fi connectivity, secure protocols including mTLS for MQTT and HTTP, inbound/outbound WebSocket and UDP, and MODBUS compatibility for industrial deployments. Built-in scripting (mjS) and webhooks enable local automation and control without cloud dependency, while on-device storage and fast reporting (down to 100 ms with custom firmware) allow detailed monitoring.

Suitable for

• Monitoring energy consumption of homes, offices, small factories
• Solar and wind generation monitoring and energy flow control
• Integration into industrial control systems via MODBUS or MQTT
• Local automation and control of Shelly or other Wi‑Fi devices

Key specifications

• Model: Shelly Pro 3EM (ALL_SHELLY_PRO_3EM)
• Maximum current: 120 A
• Frequency: 50–60 Hz
• Measurement accuracy: 1% (active energy, Class B)
• Connectivity: Wi‑Fi, LAN (Ethernet), Bluetooth, MQTT, WebSocket, UDP, mTLS
• Protocols: MODBUS support
• Historical data: up to 60 days on-device, 1-minute resolution
• Dimensions (W×D×H): 94 × 19 × 69 mm

How to use

Install the Shelly Pro 3EM on a DIN rail and connect the three-phase conductors and the neutral according to local electrical regulations. Configure network settings via the device web interface or supported integration protocol (MQTT, MODBUS or LAN). Use the built-in scripting engine (mjS) and webhooks to create local automation, or connect to a cloud or local server for data collection and visualization. For solar or bidirectional setups, configure exported/imported energy measurement to track produced and consumed energy per phase.

Recommendations

Ensure installation is performed by a qualified electrician. Verify the wiring matches the device’s input terminals and that the system current does not exceed 120 A per phase. Use secure network settings (mTLS, passwords) when integrating with remote services and create backups of custom scripts and configuration.