The Shelly EM Gen4 is a compact, multi-protocol smart energy meter designed for monitoring energy consumption in single-phase electrical systems. It can operate with up to two current transformers, allowing non-invasive measurement of two separate circuits or consumer branches. It is an ideal solution for homes, offices, apartment buildings, and small commercial energy monitoring applications.
The device measures voltage, current, active power, apparent power, energy consumption, and power factor in real time. Measurement data can be viewed on smartphones, through a web browser, in the Shelly Smart Control application, Home Assistant, or other automation platforms. Its built-in storage can locally retain up to 30 days of measurement data with 1-minute resolution.
One of the major advantages of the Gen4 version is its multi-protocol operation. It supports Wi-Fi 6, Bluetooth 5, Zigbee, and Matter, making it easy to integrate into modern smart home systems while maintaining Shelly’s well-known local control capabilities, web interface, MQTT support, webhooks, scripting, and advanced API-based integrations.
The device also features a dry contact relay output, which can be used to control an external contactor or other automation tasks. This allows not only monitoring but also automated actions based on excessive consumption, specific load thresholds, schedules, or custom automation logic. Thanks to its compact size, it can be installed inside wall boxes, electrical cabinets, or close to monitored loads.
The Shelly EM Gen4 integrates seamlessly into both cloud-based and locally controlled smart home systems. Support for Matter, Zigbee, MQTT, REST API, WebSocket, and RPC protocols makes it suitable for advanced automation environments, while Shelly Smart Control provides an easy-to-use interface for everyday monitoring and energy management.
About Shelly
Shelly is one of Europe's most innovative and recognized smart home brands, developed by the Bulgarian company Allterco Robotics. The manufacturer is particularly strong in the Wi-Fi and Bluetooth smart device market, where many devices operate without requiring a dedicated hub, making installation quick and straightforward.
The Shelly product range includes relays, sensors, smart plugs, lighting products, and professional DIN rail-mounted devices. The company places strong emphasis on local control, allowing devices to function without internet access while improving privacy and reliability.
Shelly devices provide advanced integration options including REST API, MQTT, Webhooks, Home Assistant, openHAB, Node-RED, and many other DIY and professional automation systems. Compatibility with Amazon Alexa, Google Home, and Samsung SmartThings is also supported.
Key Features
- Dual-channel single-phase monitoring: Measure up to two separate circuits or loads
- Current transformer measurement: Non-invasive energy monitoring using CT clamps
- Compatible CT clamps: Supports 50A, 80A, and 120A current transformers
- Included CT clamp: One 50A current transformer included in the package
- Local data storage: Stores 30 days of measurement data with 1-minute resolution
- Matter support: Compatible with Matter-enabled smart home ecosystems
- Multi-protocol connectivity: Wi-Fi 6, Bluetooth 5, and Zigbee support
- Zigbee repeater functionality: Extends Zigbee network coverage
- Dry contact relay output: Suitable for controlling external contactors or automation tasks
- Advanced integrations: MQTT, HTTP, HTTPS, WebSocket, RPC, webhooks, and scripting support
- Built-in protection: Overheating, overvoltage, overcurrent, and overload protection
Smart Home Protocols and Platform Compatibility
- Wi-Fi: IEEE 802.11 b/g/n/ax support with direct network connectivity
- Bluetooth: Bluetooth 5 LE support for pairing and local communication
- Zigbee: IEEE 802.15.4 support with Zigbee repeater functionality
- Matter: Compatible with Matter-enabled ecosystems
- Shelly Smart Control: Full native app support
- Home Assistant: Integration via Shelly integration, MQTT, or local APIs
- MQTT: Supported for local and server-based automation
- Webhooks: HTTP/HTTPS event-based integrations
- RPC and WebSocket: Advanced local integrations and automation servers
- Local web interface: Browser-based configuration, control, and monitoring
- HomeSeer compatibility
- ioBroker compatibility
- openHAB compatibility
- Domoticz compatibility
- nymea compatibility
- Hubitat compatibility
- HOOBS compatibility (Homebridge out of the box)
- REST API support
Smart Functions
- Real-time energy consumption monitoring
- Dual measurement channels for single-phase systems
- Active and apparent power measurement
- Active and apparent energy measurement
- Power factor monitoring
- Voltage and current measurement
- 30-day local data storage with 1-minute resolution
- CSV export of recorded values
- JSON export through RPC
- Automations based on instantaneous power or energy consumption
- Schedules and timers
- Webhook-based event triggering
- JavaScript scripting support
- Local and cloud operation
- Remote monitoring via internet connection
- Internal temperature monitoring
- External contactor control using the dry contact relay
Electrical Specifications
- Power supply: 110–240V AC, 50/60Hz
- Power consumption: < 1W
- Measurement type: Non-invasive CT clamp measurement
- Measurement channels: 2
- Voltage measurement range: 110–240V AC
- Current measurement range: 0–120A
- Compatible CT clamps: 50A, 80A, and 120A
- Included CT clamp: 50A
- Output: 1 dry contact relay for contactor control
- Maximum switching voltage: 240V AC
- Maximum switching current: 2A
- Dry contact switching: Supported
- External protection: 2A circuit breaker, B or C characteristic, 6kA breaking capacity, energy limitation class 3
- Supported loads: Resistive, capacitive, and inductive loads through a contactor with RC snubber
Technical Specifications
- Product name: Shelly EM Gen4
- Model: S4EM-002CXCEU
- Device SSID: ShellyEMG4-XXXXXXXX
- BLE Model ID: 0x1036
- Dimensions: 37 × 42 × 16 mm
- Weight: 26 g
- Installation: Wall box or compact electrical installation
- Terminal screw torque: 0.4 Nm
- Wire cross-section: 0.5–4 mm²
- Wire stripping length: 6–7 mm
- Housing material: Plastic
- Housing color: White
- Terminal color: Gray
- Operating temperature: -20°C to +40°C
- Humidity: 30–70% RH
- Maximum installation altitude: 2000 m
- Power supply: 110–240V AC, 50/60Hz
- DC power supply: Not supported
- Power consumption: < 1W
- Maximum switching voltage: 240V AC
- Maximum switching current: 2A
- Voltage measurement accuracy: ±2%
- Current measurement accuracy: ±2% between 1–50A, ±5% between 0–1A
- Measured values: Active power, apparent power, active energy, apparent energy, and power factor
- No-load threshold: 30 VA per phase
- Measurement data retention: 30 days with 1-minute resolution
- Data export: CSV and JSON via RPC
- Wi-Fi protocol: IEEE 802.11 b/g/n/ax
- Wi-Fi frequency: 2412–2484 MHz
- Wi-Fi maximum RF power: < 20 dBm
- Wi-Fi range: Up to 30 m indoors, up to 50 m outdoors
- Bluetooth protocol: Bluetooth 5 LE
- Bluetooth frequency: 2402–2480 MHz
- Bluetooth maximum RF power: < 20 dBm
- Bluetooth range: Up to 10 m indoors, up to 30 m outdoors
- Zigbee protocol: IEEE 802.15.4
- Zigbee repeater: Yes
- Zigbee frequency: 2405–2480 MHz
- Zigbee maximum RF power: < 20 dBm
- Zigbee range: Up to 100 m indoors, up to 300 m outdoors
- Processor: ESP32-C6
- Flash memory: 16 MB
- Schedules: 20
- Webhooks: 20 webhooks, up to 5 URLs per webhook
- Scripting support: Yes
- MQTT support: Yes
- Supported protocols: Zigbee, MQTT, HTTP, HTTPS, WebSocket, RPC
- Protection features: Overheating, overvoltage, overcurrent, and overload protection
- Terminals: O, L, I, N, IA, IB
- Current transformer inputs: IA and IB
- Relay output: O output, I input
