The Siemens 3RV2021-1CA25 is a SIRIUS motor protection circuit breaker with CLASS 10 trip characteristic. It snaps onto a 35 mm DIN rail and uses spring-loaded terminals.
Breaking capacity and coordination
Rated breaking capacity reaches 100 kA at 240 V, 400 V, and 500 V, and 10 kA at 690 V. That 100 kA figure at 400 V is high enough for most industrial distribution boards without needing a backup fuse — the breaker clears a bolted fault before the let-through energy damages downstream contactors. At 690 V the 10 kA rating still covers typical motor branch circuits in 690 V systems.
Protection features and mounting
Built-in phase failure detection ensures the breaker trips if one phase drops out, preventing single-phasing damage to the motor. Temperature compensation is active over the -20 to +60 °C operating range, so the thermal trip curve stays accurate regardless of panel ambient heat. The 45 mm width fits standard 45 mm module spacing on a DIN rail; depth is 97 mm, height 119 mm. Mounting position is any orientation, giving flexibility in crowded enclosures.