Motor protection circuit breaker, Size S0, Class 10
The Siemens SIRIUS 3RV2021-0JA10-ZW97 is a motor protection circuit breaker designed to protect three-phase induction motors against overload, short-circuit, and phase failure. It carries a Trip Class 10 characteristic, meaning it trips within 10 seconds at 7.2× the thermal setting — the standard for protecting standard general-purpose motors during locked-rotor conditions. The 100 kA breaking capacity at 400 V AC means it can safely interrupt a bolted fault at that level without upstream fuses, simplifying panel coordination. Phase failure detection is built in, so the breaker trips on a lost phase before the motor single-phases to destruction.
Mounting and integration
Mounts via screw fixing or snaps onto 35 mm DIN rail per DIN EN 60715. The Size S0 frame is the compact footprint for motor ratings up to around 15 kW — 45 mm wide, 97 mm deep, 97 mm tall. Any mounting position is permitted, which helps when fitting into tight panel layouts. The main circuit terminals accept 2x 1–2.5 mm² or 2x 2.5–10 mm² solid or stranded copper, terminated with M4 screws.