The Siemens 3RV2311-1AC20 is a SIRIUS circuit breaker designed specifically for starter combinations — meaning it integrates with a contactor to provide motor branch-circuit protection in a coordinated assembly. Its 100 kA breaking capacity at 400 V AC means it can safely interrupt fault currents up to that level without upstream fuses needing to clear first, which simplifies panel coordination. The same 100 kA rating holds at 240 V, 500 V, and 690 V AC, so the part covers a wide range of supply voltages common in industrial plants.
Mounts via screw or snap-on onto 35 mm DIN rail per DIN EN 60715. The 45 mm width is a standard 2.5 module footprint on a DIN rail — useful when estimating fill factor on a panel's gland plate. Clearance requirements: 50 mm upward and downward, 30 mm to the side, and zero forward or backward clearance needed. That zero forward clearance is a practical advantage in tight enclosures where you're stacking breakers close to the door.