SIRIUS transformer-protection circuit breaker, 0.2 A, Class 10
The Siemens SIRIUS 3RV1421-0BA10-ZI41 is a 3-pole circuit breaker designed specifically for transformer protection, rated at 0.2 A continuous current with Trip Class 10 thermal-magnetic release. It delivers 100 kA breaking capacity across the full voltage range from 240 V through 690 V AC, meaning it can safely interrupt fault currents up to that level without cascading upstream — critical for coordinating with downstream transformer inrush and upstream feeder protection.
The 45 mm width and 96 mm depth fit a standard 45 mm-wide DIN slot — one module width — leaving adjacent slots free for auxiliary contact blocks or other SIRIUS components. Screw-type terminals on both main and auxiliary circuits accept 2x (1... 2.5 mm²) solid or stranded, or 2x (2.5... 6 mm²) for heavier tails. Finger-safe IP20 front protection means the busbars and terminals are touch-safe once installed in an enclosure.