The Siemens 3RV1421-1DA10-ZX95 is a SIRIUS circuit breaker specifically designed for transformer protection, rated at 3.2 A continuous current and 3.2 A at 400 V AC-3 duty. Its Class 10 trip class means it handles inrush without nuisance tripping on transformer magnetizing currents — a common pain point with general-purpose breakers on a transformer primary. Breaking capacity is 100 kA at 240 V, 400 V, and 500 V AC, dropping to 8 kA at 690 V AC. That 100 kA figure at 400 V gives you serious fault-current headroom in a panel with high available short-circuit current — no need for upstream current-limiting fuses in most industrial distributions.
Main circuit connections use screw-type terminals accepting 2x (1... 2.5 mm²) solid or stranded, or 2x (2.5... 6 mm²) — covers standard panel wire up to 6 mm². AWG equivalents are 2x (14... 10). No auxiliary contacts are fitted as standard (0 provided), so if you need status feedback to a PLC, plan for a separate auxiliary switch block. Zero clearance required at the sides or rear for ventilation (0 mm backwards, 0 mm at the side), so you can pack devices tight in the enclosure. Power dissipation is 7.25 W total in hot operating state at AC, or 2.4 W per pole. That's modest for a 3.2 A device, but in a densely populated panel with multiple breakers, the cumulative heat still needs to be considered in the enclosure thermal calculation.
Shock resistance is 25 g for 11 ms. Maximum altitude is 2,000 m. Mechanical endurance is 100,000 operating cycles typical for the main contacts.