What this part is and what it does
The Siemens 3RK1901-3BA00 is an AS-Interface support module designed for load feeder modules, providing a 54 mm wide mounting base with integrated PE and neutral conductor connection for a busbar with 40 mm center-line spacing. This is a mechanical and wiring interface — it does not contain switching electronics itself, but rather supports the physical mounting and power distribution for an AS-Interface load feeder module in a panel.
Mounting and integration
The 54 mm width is designed to match the footprint of a standard Siemens S0 contactor, so it aligns cleanly on a DIN rail alongside SIRIUS devices in a motor control center layout. Mounts directly onto a busbar with 40 mm center-line spacing — this is the standard Siemens busbar pitch for their SIRIUS 3RT contactor range, so it integrates without adapter plates in a pre-bussed panel. The PE and neutral conductor connection is built into the module body, saving a separate terminal block for the protective earth and neutral rail in the AS-Interface load feeder circuit.
Required companion part
This module requires the 3RK1901-0EA power connector set — that is the separate order code for the plug-in power terminals that carry the busbar voltage to the load feeder module. Without it, the module has no electrical connection to the busbar.