Shelly Pro 3EM-400 clamps

Device identification

Name: Shelly Pro 3EM

Model: SPEM-003CEBEU

Device SSID: ShellyPro3EM-XXXXXX

BLE Model ID: –

Short description

Shelly Pro 3EM is a DIN rail–mountable three-phase energy meter that measures and reports real-time
energy data including voltage, current, active and apparent power per phase. Enhanced with Gen2 firmware
and LAN connectivity, it supports secure communication via MQTT, HTTP, and WebSocket (TLS-enabled).
The device stores up to 60 days of 1-minute interval data in non-volatile memory and features a built-in
real-time clock for accurate timestamps even when offline.



Note: The device does not include a built-in relay; contactor control requires a
Shelly Pro Add-on module.

Main features

• 4-quadrant energy measurement
• DIN rail mountable
• Supports three-phase or single-phase connections
• Current transformer inputs for non-contact measurement
• Phase sequence error detection*
• Channel-to-channel calibration**
• No-load threshold detection***
• Optical pulse indication of energy usage
• Built-in real-time clock (RTC)
• Data logs stored for up to 60 days
• Accuracy Class B (IEC 62053-21)
• Photovoltaic (PV) ready

* Detects phase sequence errors by monitoring voltage zero-crossing order (A→B→C expected). If A→C→B is detected, a phase sequence error is reported.

** Requires minimum 500 W load per channel.

*** Below 30 VA per channel, power is displayed but energy is not accumulated in statistics.

Use cases

• Residential: Track and optimize household energy use
• MDU: Multi-apartment or hotel energy monitoring
• Light commercial: Office buildings, retail, or restaurants
• Agricultural: Farms, barns, and silos
• Government/municipal: Utility and infrastructure monitoring
• University/college: Facility energy management

Simplified internal schematics

Shelly Pro 3EM internal schematics

Device electrical interfaces

Inputs: 4 line inputs (3 × L, 1 × N)

CT inputs: 4 inputs (3 for phase current, 1 for neutral)

Ethernet port: 1 RJ45 connector

Add-on interface: Shelly proprietary serial interface

⚠ CAUTION! Plug/unplug LAN cable only when powered off. Avoid touching metallic LAN contacts.

⚠ CAUTION! High voltage present on add-on interface when powered.

Connectivity

Wi-Fi

Ethernet

Bluetooth

(Each can be enabled or disabled by the user)

Safety function

Internal temperature sensing and reporting

Supported load types

• Resistive (incandescent bulbs, heaters)
• Capacitive (capacitor banks, electronics, motor capacitors)
• Inductive (LED drivers, transformers, fans, AC units, refrigerators)

User interface

Inputs: One tactile dome button

• Short press → toggles relay state on attached Shelly Pro 3EM Add-on

• Hold 5s → enables AP mode

• Hold 10s → factory reset

Outputs: LED indication

• Power → Red (power supply connected)

• Wi-Fi → Blue (AP mode), Red (STA not connected), Yellow (STA connected, Cloud disabled), Green (STA connected, Cloud enabled)

• OTA update → Flashing Red/Blue

• LAN → Green (LAN connected)

• Count → Red flashing (energy measurement in progress, flash rate proportional to energy flow)

Physical

Size (HxWxD): 94×19×69 mm ±0.5 / 3.70×0.75×2.71 in ±0.02

Weight: 62 ±1 g / 2.19 ±0.05 oz

Mounting: DIN rail

Screw terminals torque: 0.4 Nm (4.43 lbf·in)

Conductor size: 0.5–2.5 mm² (20–14 AWG; solid, stranded, and bootlace lugs)

Strip 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): N/A

Power consumption: < 3 W

External protection: Tripping characteristic B or C; 16 A max rated current; min 6 kA interrupting rating; energy limiting class 3

Sensors & Meters

Internal temperature sensor: Yes

Voltmeters (RMS per phase): 100–260 V

Voltmeters accuracy: ±1%

Ammeters (RMS via CT per phase and Neutral): 0–120 A

Compatible CT: CT 120A

Ammeters accuracy: ±1% (2–120 A), ±2% (1–2 A), ±5% (0–1 A)

Power & energy meters: Active and apparent power; active and apparent energy; power factor; fundamental active and fundamental 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 at 1 min data resolution

Data export: CSV for PQ recorded values; JSON format export via RPC

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 / 100 ft indoors; 50 m / 160 ft outdoors (depends on conditions)

Bluetooth protocol: 4.2

Bluetooth range: Up to 10 m / 33 ft indoors; 30 m / 100 ft outdoors (depends on conditions)

MCU

CPU: ESP32-D0WDQ6

Flash: 16 MB

Firmware capabilities

Webhooks: 20 (up to 5 URLs each)

Scripting: Yes

MQTT: Yes

CoAP: No