The Siemens 3RV6311-0AC10 is a SIRIUS circuit breaker sized S00, designed specifically for starter combinations — meaning it pairs directly with a contactor to form a coordinated motor starter. It's a 3-pole breaker with a magnetic short-circuit trip, rated at 0.16 A operational current at AC-3 duty (400 V), and a rated insulation voltage of 690 V. The 0.16 A rating is the motor-protection setting; the instantaneous short-circuit trip responds at 2.1 A, so it clears a fault before the contactor welds. Screw-type terminals on top and bottom accept 2x (0.75 to 2.5 mm²) solid or stranded, or 2x 4 mm².
That's a compact footprint for a motor-protective device; it leaves room for the contactor and overload relay alongside in a standard 600 mm enclosure. Relative humidity tolerance 10 to 95%.
The 0.16 A AC-3 rating at 400 V is the motor-protection setting — it's sized for a very small motor (roughly 0.06 kW at 400 V). The magnetic trip responds at 2.1 A, so it's a current-limiting device that clears a short-circuit before the contactor is damaged. Switching frequency is limited to 15 operations per hour at AC-3. Shock resistance is 25 g / 11 ms per IEC 60068-2-27; surge voltage resistance is 6 kV. Power loss is 5 W total typical.