The Siemens 3RA1921-1B Connecting Module is a dedicated link module (El. A. Mech.) that electrically and mechanically links 3RV1.2 circuit-breakers with 3RT1.2 DC actuators for synchronized multi‑unit operation. Designed for DC actuation, it is typically sold in packs of 10 pieces (1 PE = 10 items). As the official Siemens part 3RA1921-1B, it supports link functionality within 3RV1.2/3RT1.2 configurations, with size designations for the circuit-breaker and contactor listed as S0.
