Motor protection circuit breaker, 25 A, CLASS 10 — SIRIUS 3RV1021-4DA15-ZX95
The Siemens SIRIUS 3RV1021-4DA15-ZX95 is a motor protection circuit breaker rated for 25 A continuous current with CLASS 10 trip characteristic, sized for 11 kW motor loads at 400 V AC-3 duty. It snaps onto 35 mm DIN rail per DIN EN 50022 and uses screw-type terminals for the main and auxiliary circuits. CLASS 10 means the bimetal trip acts within 10 seconds at 7.2× rated current — fast enough to protect standard induction motors during locked-rotor starts without nuisance tripping on normal acceleration. Phase failure detection is built in, so a lost phase on the line side will trip the breaker rather than letting the motor single-phase and overheat. Breaking capacity is 100 kA at 240 V AC, 50 kA at 400 V AC, 10 kA at 500 V AC, and 4 kA at 690 V AC — sufficient for most industrial panel fault levels downstream of a distribution transformer. The auxiliary switch is a transverse design and the product extension allows adding auxiliary contacts without removing the breaker from the rail.
Mounting and wiring
Footprint is 45 mm wide × 97 mm high × 96 mm deep, with zero clearance required at the sides or rear — adjacent devices can butt directly. Snap-on mounting onto 35 mm DIN rail per DIN EN 50022; screw fixing also possible. Any mounting position is permitted. Main circuit terminals accept solid conductors 2×(0.5…1.5 mm²) and 2×(0.75…2.5 mm²), or stranded 2×(1…2.5 mm²) and 2×(2.5…6 mm²). AWG equivalents for main contacts are 2×(14…10). Screw-type terminals for both main and auxiliary/control circuits — no special tooling beyond a standard screwdriver.
Environmental and compliance
Operating temperature range is -20 to +60 °C; storage and transport range is -50 to +80 °C. Shock resistance rated at 25 g for 11 ms. Front-side protection class is IP20 — suitable for enclosed panel mounting, not for washdown or outdoor exposure.