What this breaker is and where it fits
The Siemens 3RV1011-0CA10-ZI45 is a SIRIUS-branded motor protection circuit breaker in the size S00 frame, designed to protect small motors and transformers on 400 V three-phase lines. Its CLASS 10 trip characteristic means it disconnects within 10 seconds at 7.2× the set current — fast enough to protect a motor winding during a stall without nuisance-tripping on a normal start-up. The adjustable overload release covers 0.18 to 0.25 A, so it's sized for fractional-horsepower motors or small control transformers drawing around that range. Rated operating current is 0.25 A at 400 V, with a power dissipation of 5.5 W in hot state (1.8 W per pole). Mounts via screw and snap-on onto 35 mm DIN rail per DIN EN 60715, in any position. The S00 footprint is 45 mm wide — same as a standard miniature circuit breaker — so it slots into a motor control center or distribution panel without eating extra rail space. Screw-type terminals on top and bottom accept up to 2.5 mm² stranded or solid.
Trip class and what it means on the bench
CLASS 10 is the standard trip class for general-purpose motor starting: it lets the breaker ride through the inrush of a direct-on-line start (typically 6–8× FLA for a few seconds) but trips fast on a locked rotor. The magnetic short-circuit trip is fixed at 8.2 A — about 33× the rated current — so it clears a bolted fault before the thermal element has time to heat. That combination (thermal CLASS 10 overload + fixed magnetic short-circuit) is what you want for a small pump, fan, or conveyor drive where the motor is started unloaded or with a light load.