What it is and where it fits
The Siemens SIRIUS 3RV2021-1GA10-0DA0 is a circuit breaker designed for system protection — meaning it guards the branch circuit against short-circuits and overloads, not just the motor. It's part of the SIRIUS family, Size S0, and carries a Trip Class 10, so it trips within 10 seconds at 7.2× the thermal setting, matching standard motor starting curves.
Breaking capacity — the number that decides selectivity
At 400 V AC the unit interrupts 100 kA. At 690 V AC that drops to 4 kA — a steep derate that matters if your panel feeds a 690 V bus. The 100 kA figure holds at 240 V and 500 V as well, so for standard 400 V distribution this breaker coordinates cleanly with upstream 100 kA-rated MCCBs without a fuse backup.
Mounting and integration
Mounts via screw and snap-on onto 35 mm DIN rail per DIN EN 60715. The 45 mm width and 97 mm depth mean it occupies a standard S0 footprint — no surprises on the gland plate. Clearance: 50 mm above and below, 30 mm to the side, zero forward or backward (–,). Any mounting position is allowed.
Lifecycle and sourcing
The lifecycle stage is current — this is an active, in-production part. No end-of-life notice or successor has been issued. For BOM freeze or second-source gate, the part is sourced to order against an RFQ through independent distribution; availability and current pricing are confirmed at quote time.