What this SIRIUS breaker is and where it fits
The Siemens 3RV2311-0KC20 is a SIRIUS circuit breaker designed specifically for starter combinations — meaning it pairs directly with a contactor to form a coordinated motor starter, protecting both the motor and the downstream wiring against short circuits and overloads. It mounts via screw or snap-on onto a 35 mm DIN rail per DIN EN 60715, and the mounting position is any orientation, which simplifies panel layout when space is tight.
Breaking capacity — the number that decides fault protection
Rated 100 kA at 400 V AC, 500 V AC, and 690 V AC, this breaker can safely interrupt a fault current up to 100,000 amps at those voltages without welding contacts or cascading failure upstream. That is a high-rupturing-capacity device — it handles the full prospective fault current of most industrial distribution panels without needing a current-limiting fuse ahead of it. At 240 V AC the breaking capacity is also 100 kA, so the same rating holds across the common low-voltage supply levels.
Physical fit and wiring
Size S00 — 45 mm wide, 97 mm deep, 106 mm tall — keeps the footprint compact for a 100 kA device. Clearance requirements: 50 mm above and below, 30 mm to the side, zero forward or backward clearance needed. Main circuit connections are spring-loaded terminals accepting 2x 0.5 to 4 mm² solid or stranded wire. The screwdriver shaft diameter is 3 mm for the terminal screws.