Siemens 3RA2921-1BA00 Link Module Size S0

Siemens 3RA2921-1BA00 is a screw-terminal electrical and mechanical link module (Size S0) for the SIRIUS 3RV2 family of circuit breakers. It is designed to be used with 3RV2.1/3RV2.2 units and provides the required interface between the breaker and downstream control components, enabling reliable wiring and mechanical linkage in electrical protection schemes. The module supports multiple configurations, including DC operation, AC/DC operation, and compatibility with a soft starter (3RW3) or a solid-state contactor (3RF34). As an accessory, it consolidates wiring and connections for compact, modular installations in control cabinets and ensures consistent fit with other Size S0 accessories within the Sirius ecosystem. Intended for screw-terminal variants, this link module helps streamline panel wiring by providing a standardized connection point for auxiliary devices and interconnections within Siemens’ protection and control portfolio. Typical applications include motor-protection schemes, protective relay assemblies, and integrated control circuits where a compact, plug-in link between the 3RV2 breaker and control devices is required.