What it is and what it does
The Siemens SIRIUS 3RV1021-1GA15-ZW95 is a motor protection circuit breaker designed for screw-type terminal wiring in the main and auxiliary circuits. It carries a continuous rated current of 6.3 A and a CLASS 10 trip characteristic, meaning it will trip within 10 seconds at 7.2× the thermal setting — fast enough to protect standard induction motors during locked-rotor starts without nuisance tripping on normal acceleration. Rated for a 2.2 kW motor at 400 V AC, it handles the typical 4-pole induction motor load on a 400 V three-phase line. Phase failure detection is built in, so a lost phase on the supply side will cause the breaker to open before the motor single-phases to failure.
Breaking capacity and coordination
This breaker delivers 100 kA breaking capacity at 240 V, 400 V, and 500 V AC, dropping to 6 kA at 690 V AC. At 400 V — the most common industrial distribution voltage — the 100 kA figure means it can interrupt a bolted fault up to that level without upstream fuses or a larger breaker needing to clear first. That gives the panel builder headroom for high-SCCR installations without cascading coordination. The 7.25 W power dissipation in hot operating state (at rated current) is modest enough that thermal derating in a crowded enclosure is rarely a concern. Mounting position is any, so vertical or horizontal DIN-rail orientation does not affect the trip curve.
Mounting and wiring
Snap-on mounting onto 35 mm standard mounting rail per DIN EN 50022, with screw terminals for both main and auxiliary circuits. The main terminals accept 2× (0.5…1.5 mm²) solid or 2× (1…2.5 mm²) stranded; the auxiliary switch terminals accept 2× (0.75…2.5 mm²) solid or 2× (2.5…6 mm²) stranded. AWG equivalents for the main contacts are 2× (14…10). IP20 on the front face means it is protected against solid objects larger than 12.5 mm (fingers) but not against moisture — standard for inside a closed panel. The auxiliary switch is transverse design and field-addable, so you can wire a remote status signal without replacing the breaker.
Lifecycle and sourcing
The lifecycle stage is marked as current, meaning Siemens still lists this as an active, in-production order code. No last-time-buy or discontinuation notice applies. For a BOM line that calls out 3RV1021-1GA15-ZW95, this part is sourced and quoted to order through independent distribution; availability and current pricing are confirmed at quote time. Substance prohibitance per the RoHS-like declaration dates to 01.05.2012, which aligns with the EU RoHS recast. The storage and transport temperature range of -50 to +80 °C and operating range of -20 to +60 °C cover most plant-floor environments without special handling.