The Siemens SIRIUS 3RV1021-0HA15-ZX95 is a motor protection circuit breaker sized for a 0.8 A continuous current, with a Class 10 trip characteristic and a 100 kA breaking capacity at 400 V AC — meaning it clears faults up to that level without upstream coordination issues. It snaps onto a 35 mm DIN rail per EN 50022 and uses screw-type terminals on both main and auxiliary circuits.
Ratings and what they mean for fit
The 0.8 A continuous rating sets the motor full-load current it protects — pair it with a motor drawing 0.8 A or less. The Class 10 trip means it disconnects within 10 seconds at 7.2× rated current, standard for standard-start induction motors. Phase failure detection is built in, so it drops the load if one phase is lost, preventing single-phasing damage. Breaking capacity holds at 100 kA across 240 V, 400 V, 500 V, and 690 V AC (–), giving high fault-current headroom even on stiff 400 V distribution. Power dissipation in hot operating state is 7.25 W — negligible for panel thermal budgeting but worth noting if the enclosure is tightly packed. Screw terminals accept solid conductors 2×(0.5…1.5 mm²) and 2×(0.75…2.5 mm²), and stranded 2×(1…2.5 mm²) and 2×(2.5…6 mm²). The auxiliary switch is transverse design and field-installable.
Mounting and environment
Mounts via screw and snap-on onto 35 mm DIN rail per EN 50022. Zero clearance required at the back and sides — no ventilation gaps needed. Any mounting position works. Operating temperature range is -20 to +60 °C; storage and transport handle -50 to +80 °C. Shock rated at 25 g for 11 ms. Front IP20 means finger-safe but not washdown.