SIRIUS motor protection circuit breaker, 12.5 A, CLASS 10
The Siemens 3RV1021-1KA10-0FJ0-ZX95 is a SIRIUS motor protection circuit breaker designed for protecting three-phase induction motors. It carries a continuous current rating of 12.5 A and is rated for 5.5 kW motor output at 400 V. The CLASS 10 trip class means it will disconnect within 10 seconds at 7.2× the set current, which is the standard for protecting standard squirrel-cage motors during startup without nuisance tripping. Breaking capacity is 100 kA at 240 V and 400 V AC, dropping to 42 kA at 500 V and 6 kA at 690 V. This gives selectivity headroom in most 400 V distribution panels — the 100 kA SCCR at 400 V means it safely interrupts faults up to that level without cascading upstream, provided the upstream device is coordinated. Phase failure detection is built in, so a lost phase on the line side will trip the breaker, protecting the motor from single-phasing. No ground fault detection on this variant.
Panel integration and mounting
Mounts via screw or snap-on onto 35 mm DIN rail per EN 50022. Width is 45 mm, height 97 mm, depth 96 mm — fits a standard 45 mm module slot. Mounting position is any, which helps in tight enclosures. Terminals are screw-type for the main circuit, accepting solid or stranded conductors: 2×(1…2.5 mm²) and 2×(2.5…6 mm²), or AWG 14–10. Front face is IP20, so finger-safe in an enclosed panel. Power dissipation is 9.25 W total in hot operating state, or 3.1 W per pole. Factor that into enclosure thermal calculations — at 12.5 A continuous, the heat load is modest but not negligible in a densely packed cabinet.
Lifecycle and sourcing
Operating temperature range is -20 to +60 °C, storage and transport -50 to +80 °C. Shock resistance rated at 25g / 11 ms. Mechanical endurance of main contacts is 100,000 operations typical.