The Siemens 3RV1917-1A is a 3-phase busbar assembly with infeed on the left, designed to feed two circuit breakers in Size S00 and Size S0 frames. It carries a 63 A continuous rating across three poles and connects via spring-loaded terminals — no screw torque to verify, no loosening from vibration.
No screw terminal to torque, which speeds assembly on repetitive builds. The 3-pole busbar feeds two breakers side-by-side on 35 mm rail; the infeed-left orientation means the supply cables land on the left end of the assembly, and the two breaker positions are to the right. Verify the breaker sizes (S00 and S0) match the frame cutouts in your enclosure layout.