Device overview
The Schneider Electric Acti9 iEM2455 (A9MEM2455) is a compact single-phase DIN-rail energy meter for submetering, cost allocation, tenant or workshop monitoring, and integration into a local energy-management system. It is the current 100 A Modbus model Schneider lists as the replacement for the discontinued 63 A iEM2155.
Core features
The meter measures active, reactive and apparent power; voltage; current; frequency; power factor; and active and reactive energy. Its four-quadrant counters distinguish forward and reverse energy, so it can record grid import and exported energy from a correctly wired single-phase solar installation. This is measurement capability, not an inverter export-limit controller.
Installation and current path
A9MEM2455 is a two-module device, approximately 35.8 mm wide, for vertical DIN-rail mounting inside an electrical enclosure. It uses a direct current path rather than external current transformers. Schneider specifies 5 A basic current and 100 A maximum rated current at 230 V line-to-neutral. Installation, upstream protection, conductor sizing and isolation must be designed and completed by qualified personnel.
For comparisons, the direct 100 A rating is important: it can suit many single-phase feeders without CT selection or CT-ratio configuration, but it is not intended for three-phase systems or currents above its terminal rating.
Accuracy and certification
Schneider specifies active energy as Class B under EN 50470-1/3 and Class 1 under IEC 62053-21, with +/-1% reading error. Reactive energy is Class 2 under IEC 62053-23, with +/-2% error. The model is MID/MIR compliant, making it relevant where regulated submetering or cost allocation requires the applicable approved installation and local legal-metrology rules. Confirm the rules for the project jurisdiction before treating any submeter as a billing instrument.
Communication and local access
The iEM2455 provides two-wire RS-485 Modbus RTU plus two pulse outputs. Schneider's current manual notes a maximum 10 m Modbus transmission line for this meter and gives a specific splitter/cable arrangement when it is combined with three-wire Modbus equipment. The display, pulse outputs and Modbus data work locally without Schneider cloud services.
Home Assistant can read the meter through the generic Modbus integration when suitable RS-485 hardware, the correct serial settings and manual register mapping are provided. This is conditional standards-based compatibility, not a native Schneider iEM2455 integration.
Suitable scenarios
The device is a strong fit for a single-phase main or sub-feed that needs compact direct-connected metering, local Modbus access, import/export energy totals, or MID/MIR-class submetering. Typical uses include apartments, small commercial units, workshops, heat-pump or EV subcircuits, and single-phase solar monitoring.
It is a weaker fit when three-phase measurement, circuit-by-circuit CT monitoring, wireless connectivity, a built-in cloud dashboard, or a long multidrop communications run is required.
Advantages and limitations
Advantages include a compact two-module footprint, direct 100 A measurement, formal energy accuracy classes, four-quadrant energy counters, pulse outputs and local Modbus. Key limitations are single-phase-only operation, qualified electrical installation, no native Wi-Fi or Ethernet, and the manual's 10 m Modbus line guidance for this model.
Purchase and official sources
Use the exact A9MEM2455 reference when ordering; nearby iEM2435 and older iEM21xx models have different communications or current limits. Check regional certification, distributor stock, tax and delivery before purchase.