Energy measurement device Shelly EM+50A 50A with external CT transformer

Shelly EM + 50A Transformer Kit (Energy Consumption Measurement) — a combined system for monitoring and measuring electricity usage in residential or small commercial installations. The kit includes the Shelly EM energy monitor and a 50A external current transformer (CT) to measure currents up to 50 A and deliver accurate readings for real-time and historical analysis. The device provides day, week, month and year consumption statistics and supports local and remote control over monitored circuits.

Advantages

The Shelly EM offers two single-phase channels for energy consumption measurement, low device energy use (below 1 W), and Wi‑Fi connectivity (802.11 b/g/n) for easy integration into existing networks. The included 50A CT has 1% accuracy, a ferrite core and a 60 cm cable, enabling precise current conversion without affecting the electrical system’s operation. Built-in functions include contactor control, overheating protection, smart on/off, weekly scheduling and sunrise/sunset automation.

Suitable for (tasks / use cases)

• Real-time monitoring of household or small commercial electricity consumption
• Historical usage analysis (daily, weekly, monthly, yearly)
• Load monitoring and distribution between circuits
• Energy cost tracking and optimization
• Integration into home automation systems for remote control and scheduling

Key specifications

• AC power supply: 110–230 V, 50/60 Hz
• Channels: 2 channels (single-phase)
• Wi‑Fi: 802.11 b/g/n; range up to 30 m indoors, up to 50 m outdoors
• Device power consumption: below 1 W
• Operating temperature: 0 to +40 °C
• Contactor control: up to 2 A
• Protection: device overheating protection (no overload protection)
• Dimensions (Shelly EM): 39 x 36 x 17 mm
• CT primary current: 50 A; secondary current: 16.67 mA; accuracy: 1%
• CT core: ferrite; inner diameter: 11 mm; cable length: 60 cm; dimensions: 23.5 x 41.5 x 26 mm
• CT electrical strength: 3000 VAC 1 mA 60 s; load resistance: 20 Ω; saturation current ≥85 A
• Compatibility: Shelly EM

How to use

Install the Shelly EM in an appropriate electrical enclosure and connect its AC power supply (110–230 V). Fit the 50A current transformer around the conductor to be measured and route the CT cable to the Shelly EM input following the manufacturer’s wiring diagram. Configure Wi‑Fi settings and set up channels in the Shelly app or web interface to view real‑time and historical consumption data. Use contactor control and scheduling features to automate switching where required.

Usage recommendations

Ensure installation is performed by a qualified electrician. Verify CT orientation and secure connections before powering the circuit. Do not exceed the CT primary current rating (50 A); allow for proper ventilation and keep the device within the specified operating temperature range.