What this SIRIUS breaker is and what it does
The Siemens 3RV2021-4BA10-0DA0 is a SIRIUS-branded circuit breaker designed for system protection — meaning it guards the branch circuit, not a specific motor, against overcurrent and short-circuit faults. It carries a CLASS 10 trip characteristic, so it clears faults fast enough to protect downstream motor starters and contactors during a stalled-rotor or locked-rotor event. The breaker is rated for a rated value range of 20... 690 V, and at 400 V it coordinates with a gG 63 A backup fuse. This is a size S0 frame — 45 mm wide, 97 mm deep, 97 mm tall — which is the standard footprint for moderate motor branch circuits up to around 5.5 kW at 230 V. It mounts via screw and snap-on onto 35 mm DIN rail per DIN EN 60715, in any mounting position. The screw-type terminals on the main current circuit accept 2x (1... 2.5 mm²) or 2x (2.5... 10 mm²) solid or stranded copper.
Breaking capacity — what the ratings mean for your panel
The 3RV2021-4BA10-0DA0 delivers a rated ultimate short-circuit breaking capacity (Icu) of 100 kA at 240 V AC, 55 kA at 400 V AC, 10 kA at 500 V AC, and 4 kA at 690 V AC. These are the maximum fault currents the breaker can safely interrupt without welding or exploding — critical for SCCR (short-circuit current rating) compliance of the entire panel. At 400 V the service breaking capacity (Ics) is 25 kA, meaning it can clear a fault and still be reclosed without replacement, which matters for uptime in continuous processes.
Panel integration and clearance
When mounting in an enclosure, the required clearances are: 50 mm upwards, 50 mm downwards, 30 mm to the side, 0 mm forwards, 0 mm backwards. The forwards and backwards zero-clearance spec means it can be mounted flush against a panel backplate or a busbar cover without derating. The screwdriver shaft diameter for the terminals is 5 to 6 mm.