Siemens 3RV2021-4BA10 — SIRIUS 3RV20 motor protection circuit breaker, frame size S0. Rated up to 32 A adjustable, IEC 60947-4-1 type-2 coordination with paired 3RT2 contactor. SIRIUS 3RV2 MPCB 14-20A, trip class 10, 50kA at 400V. Motor protection up to 9kW at 400V. Installed as the primary motor branch-circuit protection device between the incoming feeder and the contactor.