The Siemens 3RV6411-0CA10 is a SIRIUS circuit breaker sized S00, designed specifically for transformer protection. It carries a rated operational current of 0.25 A across three poles, with a thermal overload release (Class 10) and a magnetic short-circuit trip. The 690 V rated insulation voltage and 50-60 Hz operating frequency cover standard industrial supply voltages. The 0.25 A rating is the key fit number — this breaker is sized for the inrush and continuous current of a small control transformer, not a motor or general branch circuit. Class 10 trip means it allows a brief overload (up to about 10 seconds at 6x rated current) before opening, matching transformer magnetizing inrush without nuisance tripping.
The S00 footprint — 45 mm wide, 96 mm deep, 97 mm tall — fits standard 45 mm-wide DIN slots. That means you can pack breakers tight side-to-side but need headroom for wiring and heat dissipation. Screw-type terminals on top and bottom accept 2x (0.75–2.5 mm²) solid/stranded or 2x (0.5–1.5 mm²) finely stranded with ferrules. Torque to 0.8–1.2 N·m. The 5 W typical power loss means no forced cooling needed in a standard IP20 enclosure, but keep the 50 mm clearance above for warm air rise.
The part carries a substance prohibitance date of 05/01/2012. Standard Siemens documentation is available on request.