Device overview
The Schneider Electric Acti9 iEM3155 (A9MEM3155) is a compact direct-connected energy meter for submetering and energy-allocation work. It measures current, voltage, active and reactive power, and signed active, reactive and apparent energy without external current transformers on circuits up to 63 A.
Core measurement capabilities
The meter supports 1P+N, 3P and 3P+N networks at 100-277 V line-to-neutral or 173-480 V line-to-line, 50/60 Hz. Signed four-quadrant registers distinguish direction, so it can record both imported and exported energy when wired and configured correctly.
Active-energy accuracy is Class 1 under IEC 62053-21 and IEC 61557-12, and Class B under EN 50470-3. MID certification makes it relevant where regulated submetering evidence is required, subject to local rules and installation practice.
Installation
The iEM3155 clips onto a DIN rail and occupies 90 mm. It is a direct-input 0-63 A meter and does not use external CTs. Installation belongs inside a suitable electrical panel and should be completed by a qualified electrician.
Communication and local access
An isolated RS-485 port exposes Modbus RTU at 9.6, 19.2 or 38.4 kbaud. Meter readings can remain local; no Schneider cloud service is required. One digital input and one static digital output support tariff or pulse/alarm workflows.
Home Assistant compatibility
Home Assistant can read the iEM3155 through its official Modbus integration using a USB-to-RS-485 adapter or suitable gateway. This is conditional manual integration, not native discovery: configure the serial path, unit address and Schneider register map.
Solar import and export
The official datasheet specifies signed four-quadrant energy measurement, supporting import/export monitoring for grid-connected solar or other bidirectional flows. This is measurement only; the meter does not control an inverter or enforce export limits.
Best fit and limitations
The iEM3155 suits DIN-panel submetering, building-management systems, multi-tariff allocation and projects valuing local industrial protocols and formal accuracy. It is less convenient than an app-first Wi-Fi monitor for users who do not want to configure Modbus.
Purchase and official resources
Availability varies by Schneider Electric market and distributor. Confirm local MID requirements, stock, pricing, panel space and installer requirements before purchase.