What this part is and what it does
The Siemens SIRIUS 3RV1021-0DA10-ZW98 is a motor protection circuit breaker designed for motor protection, rated at 0.32 A continuous current with a CLASS 10 trip characteristic — meaning it will trip on overload fast enough to protect a standard induction motor before the winding temperature exceeds its limit, provided the motor's thermal time constant aligns with that curve. Its breaking capacity is 100 kA at 400 V AC (also 100 kA at 240 V, 500 V, and 690 V AC), so it can safely interrupt a fault current up to that level without upstream fuses or breakers needing to coordinate — a strong SCCR (short-circuit current rating) for a device this compact. Phase failure detection is built in, which is critical for three-phase motor protection: if one phase drops out, the breaker will trip before single-phasing cooks the motor.
Mounting and integration
Mounts via screw and snap-on onto a 35 mm standard mounting rail per DIN EN 50022 — the same rail used across the SIRIUS family, so it clips into the same panel profile as the contactor and overload relay downstream. Dimensions are 45 mm wide, 97 mm high, 96 mm deep — a 45 mm footprint that fits a standard 45 mm slot in a motor control center (MCC) bucket or a standalone DIN-rail enclosure. IP20 on the front means finger-safe from the panel face; the rear and sides are open to the enclosure interior, so the enclosure itself must provide the environmental seal.
Wiring and terminals
Main circuit terminals are screw-type, accepting solid or stranded conductors: 2x (1... 2.5 mm²) and 2x (2.5... 6 mm²) per clamp — enough for the 0.32 A rating but also for the larger wire sizes needed to carry the fault current without overheating the terminal. Auxiliary switch option is present, though no auxiliary contacts are pre-installed (0 for auxiliary contacts,) — the buyer adds the aux block separately if remote status is needed.