Shelly Pro 3EM
Device Identification
- Device name: Shelly Pro 3EM
- Device model: SPEM-003CEBEU
- Device SSID: ShellyPro3EM-XXXXXX
Short Description
The Shelly Pro 3EM is a DIN rail-mountable three-phase energy meter. Enhanced with full gen2 firmware flexibility and LAN connectivity, it offers professional integrators expanded options for end-customer solutions. It can operate standalone in a local LAN or Wi-Fi network, or be managed remotely via cloud-based home automation services using MQTT, HTTP, and WebSocket protocols. All inbound connections support TLS encryption.
The device provides real-time measurements of accumulated energy, as well as instantaneous voltage, current, active power, and apparent power per phase. Data is stored in non-volatile memory and can be retrieved for up to 60 days at 1-minute intervals.
It features a built-in real-time clock (RTC) to maintain accurate time even if the connection to an SNTP server is lost.
Users can remotely access, configure, and monitor the device, while the device can also communicate with automation systems—provided both are within the same network infrastructure.
An embedded web interface enables monitoring, control, and configuration of device settings.
⚠ NOTICE! The device does not include a built-in relay. Contactor control is achieved by connecting a Shelly Pro Add-on module to the Shelly Pro 3EM.
Features
- 4-quadrant power measurement
- DIN rail mounting
- Multiple connectivity options (Wi-Fi, Ethernet, Bluetooth)
- Current transformer (CT) inputs for phase and neutral current sensing
- Phase sequence error detection* (optional)
- Channel-to-channel calibration**
- No-load threshold***
- Optical pulse output for energy usage indication
- Built-in real-time clock
- Data logging capabilities
- Accuracy Class B (IEC 62053-21)
- Photovoltaic (PV)-ready design
* Phase sequence error detection uses zero-crossing events from phase voltages. The expected sequence is Phase A → Phase B → Phase C. If the detected sequence is Phase A → Phase C → Phase B, a
phase_sequenceerror is reported when the feature is enabled.** Calibration requires at least 500 W load per channel.
*** When total load across all three channels drops below 30 VA per channel, measured power values are displayed, but no energy accumulation occurs. A
No load thresholdnotification appears in the web interface and mobile app.
Main Applications
- Residential buildings
- Multi-dwelling units (MDUs): apartments, condominiums, hotels, etc.
- Light commercial: small offices, retail stores, restaurants, gas stations
- Agricultural: farms, barns, silos
- Government and municipal facilities
- Universities and colleges
Simplified Internal Schematics
Device Electrical Interfaces
Inputs
- 4 line inputs via screw terminals: 3 L (Phases A, B, C), 1 N (Neutral)
- 4 CT inputs: 3 for measuring L currents (A, B, C), 1 for N current (optional)
Ethernet Port
- 1 × RJ45 connector
⚠ CAUTION! Always disconnect or connect the LAN cable only when the device is powered off. Ensure the connector housing is non-metallic in user-contact areas.
Add-on Interface
- Proprietary serial interface for Shelly Pro Add-on modules
⚠ CAUTION! High voltage is present on the add-on interface when the device is powered. Exercise caution during installation and maintenance.
Connectivity
- Wi-Fi (2.4 GHz)
- Ethernet (RJ45)
- Bluetooth 4.2
Each connectivity method can be independently enabled or disabled via configuration.
Safety Features
- Internal temperature sensing and reporting
Supported Load Types
- Resistive (e.g., incandescent bulbs, heaters)
- Capacitive (e.g., LED drivers, capacitor banks, electronic equipment, motor start capacitors)
- Inductive (e.g., transformers, fans, refrigerators, air conditioners)
User Interface
Input
- One tactile dome button:
- Brief press: Toggle the state of the relay on the attached Shelly Pro 3EM Switch Add-on.
- Hold 5 seconds: Activate Device Access Point (AP) mode.
- Hold 10 seconds: Perform factory reset.
Outputs (LED Indicators)
- Power: Red light — indicates power supply is connected.
- Wi-Fi (status varies):
- Blue: AP mode
- Red: STA mode, not connected to Wi-Fi
- Yellow: STA mode, connected to Wi-Fi, but not to Shelly Cloud (or Cloud disabled)
- Green: STA mode, connected to Wi-Fi and Shelly Cloud
- Flashing red/blue: OTA firmware update in progress
- LAN: Green light — indicates Ethernet connection established.
- Count: Red LED flashes at a frequency proportional to energy flow through the circuit, based on configured settings.
Specifications
| Category | Specification |
|---|---|
| Physical | |
| Size (H×W×D) | 94 × 19 × 69 ±0.5 mm / 3.70 × 0.75 × 2.71 ±0.02 in |
| Weight | 62 ±1 g / 2.19 ±0.05 oz |
| Mounting | DIN rail |
| Screw terminal max torque | 0.4 Nm / 4.43 lbin |
| Conductor cross-section | 0.5 – 2.5 mm² / 20 – 14 AWG (solid, stranded, bootlace lugs) |
| Stripped length | 6 – 7 mm / 0.24 – 0.28 in |
| Shell material | Plastic |
| Color | White |
| Environmental | |
| Ambient temperature | -20 °C to 40 °C / -5 °F to 105 °F |
| Humidity | 30% – 70% RH |
| Max altitude | 2000 m / 6562 ft |
| Electrical | |
| Power supply (AC) | 100 – 260 V, 50/60 Hz |
| Power supply (DC) | Not applicable |
| Power consumption | < 3 W |
| External protection | Tripping characteristic B or C, max 16 A rated current, min 6 kA interrupting rating, energy limiting class 3 |
| Sensors & Meters | |
| Internal temperature sensor | Yes |
| Voltmeters (RMS, per phase) | 100 – 260 V |
| Voltmeter accuracy | ±1% |
| Ammeters (RMS via CT, per phase & neutral) | 0 – 120 A |
| Compatible CT | CT 120A |
| Ammeter accuracy | ±1% (2–120 A), ±2% (1–2 A), ±5% (0–1 A) |
| Power & Energy Meters | Active & apparent power, active & apparent energy, power factor, fundamental active/reactive energy |
| Channel-to-channel calibration minimum load | 500 W per channel |
| No-load threshold | 30 VA per channel |
| Measurement data storage | At least 60 days of 1-minute resolution data |
| Data export | CSV format (PQ recorded values); JSON via RPC API |
| Radio | |
| 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 indoors / 50 m outdoors (varies with environment) |
| Bluetooth protocol | 4.2 |
| Bluetooth range | Up to 10 m indoors / 30 m outdoors (varies with environment) |
| MCU | |
| CPU | ESP32-D0WDQ6 |
| Flash memory | 16 MB |
| Firmware Capabilities | |
| Webhooks (URL actions) | 20 hooks, up to 5 URLs per hook |
| Scripting | Yes |
| MQTT | Yes |
| CoAP | No |
Basic Wiring Diagrams
Legend
Terminals
- A: Phase A input
- B: Phase B input
- C: Phase C and power supply input
- N: Neutral terminal
Wires
- LA: Phase A live wire (110–240 V)
- LB: Phase B live wire (110–240 V)
- LC: Phase C live wire (110–240 V)
- L: Single-phase live wire (110–240 V)
- N: Neutral wire
Current Transformers
- IA: Phase A CT input
- IB: Phase B CT input
- IC: Phase C CT input
- IN: Neutral CT input (optional; not included with device)
CT Labels
- CTA: Phase A current transformer
- CTB: Phase B current transformer
- CTC: Phase C current transformer
- CTN: Neutral current transformer (optional; not included)
Shelly Smart Control
Shelly Web User Interface
Troubleshooting
(Content pending)
Components and APIs
Compliance
- Shelly Pro 3EM Multilingual EU Declaration of Conformity (2025-07-23)
- Shelly Pro 3EM 120A UK PSTI ACT Statement of Compliance
- Shelly Pro 3EM AU/NZ Certificate for Suitability
Compliance Archive: