The Siemens 3RV1021-0EA15-ZX95 is a SIRIUS motor protection circuit breaker rated for 0.4 A continuous current with a 100 kA breaking capacity at 400 V AC — enough to handle high-fault utility feeds without upstream fuses. It's designed for motor protection, includes phase failure detection, and trips on Class 10 overload curves, so it matches standard IEC motor starting profiles.
Mounting and integration
Snaps onto 35 mm DIN rail per DIN EN 50022 and can be mounted in any position. At 45 mm wide, it fits a standard single-module slot in a panel. Screw terminals on both main and auxiliary circuits — solid wire 2x (0.5... 1.5 mm²) or 2x (0.75... 2.5 mm²), stranded 2x (1... 2.5 mm²) or 2x (2.5... 6 mm²).
Key ratings and what they mean
The 0.4 A continuous rating sets the motor full-load current this breaker protects — pair it with a motor nameplated at or below that value. The 100 kA breaking capacity holds across 240 V, 400 V, 500 V, and 690 V, so it's suitable for installations with high available fault current without needing a current-limiting upstream device. Trip Class 10 means it will trip within 10 seconds at 7.2× the current setting, fast enough for most standard induction motors. Phase failure detection is built in, so a lost phase won't let the motor single-phase and burn.