SONOFF POW Ring (POWCT) Smart Power Meter Features ESP32 MCU and Split-Core CT Clamp for 100A Energy Monitoring

30 June, 2025

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In the past few years, SONOFF has become a trendsetter among Smart Home users for effortlessly monitoring the energy usage of household electrical devices. SONOFF POWCT from ITEAD is the first Split Core Current Transformer Clamp-based Wi-Fi power meter which has the ability to measure the current flow or total power-consumption up to 100A, providing no physical contact with live wires thereby reducing the risk factor during installation. The SONOFF POW Ring is not only a Smart Power Meter with overload protection support but also a switch, which means that besides measuring energy usage and management, it also features a small-sized relay to trigger a magnetic contactor to control high-load electrical devices.

Unlike SONOFF’s existing energy monitoring devices such as POW Elite, SPM, DualR3, POW3, and POW Origin built around the ESP8266 MCU, this new device, better known as EVPOWCT, relies on an ESP32 microcontroller as well as an external high-gain SMA antenna for control and wireless connectivity with a range of up to 130 meters. This makes it suitable for measuring electricity usage at the main circuit breaker, energy generated from solar panels, or even for Electric Vehicle (EV) home chargers.

SONOFF POW Ring Smart Power Meter (POWCT) specifications:

MCU: Espressif ESP32 dual-core Wi-Fi + Bluetooth microcontroller
Wireless connectivity: 2.4GHz Wi-Fi 4 (802.11 b/g/n) with external SMA antenna connector
Current transformer (CT) interface: RJ9 port (supports only single-phase power measurement)
CT detection range: 0 to 100A
Measurement category: CAT II, 0–100A, 300V Max
Relay output: Supports 0–240V AC and 0–30V DC up to 2A
Display: Integrated LCD screen for real-time power and energy readings
User controls: Power/pairing button (single press for power, 5s press for pairing mode)
LED indicators: Power (Red), Wi-Fi status (Blue)
Power input: 100–240V AC, 50/60Hz
Operating temperature: -40°C to +50°C
Humidity tolerance: 5% to 95% RH (non-condensing)
Enclosure: V-0 rated flame-retardant housing
Dimensions: 98 x 54 x 31mm
Weight: 120g (excluding accessories)

SONOFF POW Ring (POWCT) is managed using the eWeLink app with which users can check real-time, daily, monthly, and yearly power consumption in their Android/iOS mobile app, and also set timers, power consumption goals via push notifications, configure voice control (Google Assistant and Amazon Alexa), Home Assistant, and automations through IFTTT. POWCT also works with Apple HomeKit technology via Matter to control smart home electrical appliances.