Device Overview

Eastron SDM120-M is a compact single-phase DIN-rail multifunction energy meter. It is aimed at installer-led metering jobs where a narrow one-module meter is easier to fit than a larger 100 A meter, and where local wired readings matter more than an app-first monitoring experience.

The reviewed Eastron sources position SDM120-M for single-phase residential, utility, industrial, solar PV, and EV charging metering. The EV charging page also frames it as suitable for 7 kW AC EV charging piles.

Core Characteristics

  • Single-phase 1P2W / 1P+N metering.
  • 45 A maximum direct load with 5 A base current.
  • DIN-rail mounting in an indoor electrical cabinet.
  • Active energy, reactive energy, voltage, current, power, power factor, frequency, and demand measurements.
  • Bidirectional import/export energy measurement.
  • Two pulse outputs plus RS485 Modbus RTU on the SDM120-M variant.

Installation And Measurement Fit

SDM120-M is a direct-connected meter. It does not need external current transformers, which keeps the installation compact and avoids CT selection errors. The tradeoff is the 45 A maximum direct-load limit, so it fits low-current single-phase circuits and many 7 kW EV charger metering jobs better than high-current whole-home mains monitoring.

Compatibility And Data Access

The official product page and manual document RS485 Modbus RTU communication, configurable Modbus addressing, baud-rate settings, and pulse outputs. That supports local data collection through a compatible RS485 adapter, gateway, inverter, EMS, or building-management controller.

Home Assistant support should be read as standards-based Modbus integration potential through compatible RS485 hardware, not as an Eastron-native Home Assistant integration.

Strengths And Limits

SDM120-M is useful where the buyer needs a narrow, source-backed, MID-oriented single-phase meter with bidirectional readings and local Modbus access. It is not a battery, inverter, EV charger, or standalone gateway, and it should not be selected for circuits above the 45 A direct-load rating.