What it is and what it does
The Siemens 3RV1011-0CA20-ZX95 is a SIRIUS motor-protection circuit breaker designed for 3-phase AC motors up to 0.06 kW at 400 V. It combines a thermal-magnetic overload relay and a short-circuit release in one 45 mm-wide package that snaps onto a 35 mm DIN rail per EN 50022. Rated continuous current is 0.25 A, with a CLASS 10 trip characteristic — meaning it will trip within 10 seconds at 7.2× rated current, matching the thermal curve of standard squirrel-cage induction motors during start-up. The 100 kA breaking capacity at 400 V AC means it safely clears a bolted fault up to that level without upstream fuses or a larger breaker, as long as the prospective short-circuit current at the panel does not exceed that rating. Phase failure detection is built in, so if one phase drops out, the breaker trips before single-phasing damages the motor winding. Ground fault detection is not included — that requires a separate residual-current device or a different SIRIUS variant.
Mounting and wiring
Mounts via screw or snap-on onto 35 mm standard rail per DIN EN 50022. The 45 mm width and 90 mm height fit a standard motor-starter row alongside a contactor of the same frame. Any mounting position is allowed, and the IP20 front protection means the terminals are finger-safe but the unit is not sealed against washdown — it belongs inside an IP54 or higher enclosure. Main circuit terminals are spring-loaded, accepting 2x (0.25 to 2.5 mm²) solid or 2x (0.25 to 1.5 mm²) fine-stranded with ferrule. The auxiliary switch option allows a separate signal contact for remote status.
Environmental and endurance
Rated for operation from -20 to +60 °C, with storage and transport range of -50 to +80 °C. Shock resistance is 25g for 11 ms, and mechanical endurance of the main contacts is rated at 100,000 operations. Maximum switching frequency at AC-3 duty is 15 operations per hour. Altitude limit is 2,000 m without derating.