What this part is and what it does
The Siemens 3RV1021-1HA10-ZW96 is a SIRIUS motor protection circuit breaker with screw-type terminals, designed to protect three-phase motors against overload, short-circuit, and phase failure. It carries a rated continuous current of 8 A and switches a 3 kW motor at 400 V AC. The Trip Class 10 characteristic means it will trip within 10 seconds at 7.2× the thermal setting — fast enough to protect standard induction motors during a locked-rotor event. Phase failure detection is built in, so a lost phase on the line side will trip the breaker before the motor single-phases to failure. The 45 mm wide body snaps onto a 35 mm DIN rail per DIN EN 50022, with screw and snap-on fastening. The IP20 front protection means it is safe for finger contact inside an enclosed panel but not for washdown environments. Mounting position is any, which helps when panel layout is tight.
Breaking capacity and selectivity
The interrupting ratings are 100 kA at 240 V AC, 100 kA at 400 V AC, 42 kA at 500 V AC, and 6 kA at 690 V AC. At 400 V — the most common industrial distribution voltage — the 100 kA SCCR means this breaker can be installed on a panel fed by a transformer of virtually any standard size without needing a current-limiting upstream device. At 690 V the 6 kA rating is lower but still covers most motor branch circuits in 690 V systems where the available fault current is typically below that level. Rated insulation voltage is 690 V, and surge voltage resistance is 6 000 V, which aligns with IEC 60947-2 overvoltage category III for fixed-installation equipment.
Terminal capacity and wiring
Screw-type terminals on both the main and auxiliary/control circuits. Each pole accepts 2× (1 … 2.5 mm²) solid or stranded, or 2× (2.5 … 6 mm²) — the larger cross-section is useful for looping through the line feed without a separate terminal block. Finely stranded wire with core end processing (ferrules) is also supported in the same ranges. AWG equivalents are 2× (14 … 10).
Environmental and compliance
Operating temperature range is -20 to +60 °C; storage and transport range is -50 to +80 °C. Shock resistance is 25 g for 11 ms. RoHS compliance date is 01.05.2012, meaning the part meets the EU RoHS substance restrictions from that date forward.