SIRIUS 3RV2021-4BA10-0BA0 motor-protection circuit breaker
The Siemens 3RV2021-4BA10-0BA0 is a SIRIUS motor-protection circuit breaker in the S0 frame size, designed for protecting three-phase motors against overload and short-circuit. It snaps onto a 35 mm DIN rail per DIN EN 60715 or screws directly to a mounting plate, making panel integration straightforward. The 45 mm width and 97 mm depth fit standard motor-starter footprints. Trip Class 10 means it trips within 10 seconds at 7.2× the thermal setting — the right response for standard induction motor starts without nuisance tripping on normal acceleration. Rated breaking capacity hits 100 kA at 240 V AC, 55 kA at 400 V AC, and 10 kA at 500 V AC. At 690 V AC it clears 4 kA. These figures cover most industrial distribution fault levels downstream of a transformer.
Mounting and panel fit
Mounts in any position; screw and snap-on onto 35 mm DIN rail per DIN EN 60715. Required clearance: 50 mm upward, 50 mm downward, 30 mm at the sides. Zero clearance needed forward or backward — tight panel layouts work. Terminals accept 2× (1 to 2.5 mm²) or 2× (2.5 to 10 mm²) solid or stranded copper. M4 screw-type terminals on the main circuit, screwdriver shaft diameter 5 to 6 mm.
Lifecycle and sourcing
Phase failure detection is built in, but ground fault detection is not — plan a separate ground-fault relay if the application requires it. Operates from -50 to +60 °C; temperature compensation active from -20 to +60 °C. Stores and ships from -50 to +80 °C.