What it is and what it connects to
The Siemens 3RK1903-0AL00 is a 130 mm terminal module purpose-built for the ET200S High Feature Reversing starter. It includes the supply line connection, meaning it handles the incoming power feed to the reversing starter assembly within the ET200S distributed I/O system. This is not a standalone contactor or overload — it is the interface module that physically and electrically ties the reversing starter into the ET200S backplane and the line supply.
Compliance and substance restrictions
The substance prohibitance date is 05/01/2012, which aligns with the European RoHS compliance timeline for industrial equipment. This means the module meets the restricted-substance limits that took effect in 2012, covering lead, mercury, cadmium, and the other RoHS substances. No additional compliance documentation (UL, CSA, CE) is listed in the spec record, but the ET200S platform typically carries CE marking for the European market as part of the Siemens SIRIUS family.
Integration into the ET200S system
This module snaps onto the standard 35 mm DIN rail per DIN EN 50022, the same rail used by the ET200S interface modules and I/O slices. The 130 mm width occupies a specific slot in the reversing starter configuration — it is not a general-purpose terminal block. The supply line connection means it accepts the incoming three-phase power and distributes it to the reversing contactor assembly within the ET200S High Feature starter. For a panel builder, this module is the power entry point for the reversing starter group; the wiring from the line supply lands here, not directly on the contactors.