Device Overview
The CircuitSetup Expandable 6 Channel ESP32 Energy Meter is an open-source, local-first energy monitoring board built around ESP32 firmware options and two ATM90E32AS metering ICs. It is best understood as a maker / advanced-install energy-meter platform rather than a sealed app-first consumer monitor.
The main board measures six CT channels and one voltage reference by default. With add-on boards, the system can scale to many more channels, making it useful for whole-home monitoring, subpanels, solar production, large branch circuits, and multi-voltage projects where a flexible CT layout matters.
Core Monitoring Fit
This device is strongest when the buyer is comfortable with electrical-panel CT work, ESPHome or EmonESP setup, and calibration. It can measure active power, reactive power, apparent power, power factor, frequency, and related energy values from supported CT and voltage-reference inputs.
Installation And Sensing
The board uses external current transformers and an AC-AC transformer voltage reference. The official documentation lists CT options from small branch-circuit sensors through 200 A CTs, and explains that calibration is important when CTs, transformers, lead lengths, or board revisions differ.
Home Assistant And Local Data
ESPHome is the recommended current software path. CircuitSetup documents flashing through its ESP Web Installer and adopting the device into Home Assistant / ESPHome Device Builder. Local ESPHome, EmonESP, MQTT, and related open-source paths make this a good fit for users who want local ownership of energy data.
Solar And Phase Use
Official documentation lists North American split-phase service, single-phase 230/240 V service, and three-phase projects as typical use cases, provided the correct voltage references are used. Solar monitoring is also an intended use case when CTs are placed and configured appropriately.
Buyer Notes
This is not a simple plug-and-play retail monitor. It is best for technically confident users, integrators, or open-source energy-monitoring projects. Current public purchase availability is variable: the reviewed Tindie listing showed the main board as out of stock, so buyers may need to follow the GitHub project, CircuitSetup store links, Tindie, or community channels for current availability.