SIRIUS transformer-protection circuit breaker, 0.4 A, Class 10
The Siemens SIRIUS 3RV1421-0EA15 is a circuit breaker designed specifically for transformer protection, carrying a continuous current rating of 0.4 A and a Trip Class 10 characteristic. It provides phase failure detection and offers a symmetrical breaking capacity of 100 kA across all AC voltage levels from 240 V to 690 V, meaning it can safely interrupt fault currents up to that magnitude without upstream coordination issues. The 45 mm wide housing mounts via screw and snap-on onto a standard 35 mm DIN rail per EN 50022, fitting into a standard control-panel layout.
Trip Class 10 means the bimetal element will trip within 10 seconds at 7.2× rated current, protecting the transformer winding from sustained overload without nuisance tripping on normal inrush. The 100 kA breaking capacity at 400 V and 690 V gives the breaker enough interrupting capability to serve as the sole branch-circuit protection in most industrial panels, even on high-fault-capacity mains.
The 45 mm width and 96 mm depth fit a standard 80 mm deep enclosure with room for gland plates. Screw terminals accept solid conductors up to 2x 2.5 mm² and stranded up to 2x 6 mm². Zero clearance required at the sides or rear for heat dissipation, so adjacent breakers can be ganged without derating.
Substance prohibitance per RoHS applies from 01.05.2012. Operating temperature range is -20 to +60 °C, storage and transport from -50 to +80 °C. Shock resistance rated at 25g for 11 ms. Surge voltage resistance rated at 6 000 V.