What the ratings mean for fit
The Siemens SIRIUS 3RV2021-1GA10-ZW97 is a motor protection circuit breaker designed for the AC-3 duty cycle typical of squirrel-cage induction motors. Its Trip Class 10 rating means it will trip within 10 seconds at 7.2× the thermal setting — a standard match for most general-purpose motor starts, including pumps, fans, and compressors. The 100 kA breaking capacity at 400 V AC gives it enough interrupting capability to sit on a high-fault panel without needing upstream fuses; the same rating holds at 240 V and 500 V. Phase failure detection is built in, so a lost phase on the line side will drop the motor before single-phasing damages the winding. Mounting is screw and snap-on onto 35 mm DIN rail per DIN EN 60715, which means it clips into the same rail as contactors and overload relays in a standard motor control center. The 45 mm width is a single-module footprint — one slot on the rail, leaving room for auxiliary contacts or a separate contactor next to it. Any mounting position is allowed, so vertical or horizontal rail orientation works in tight enclosures.
Sourcing and lifecycle reality
The lifecycle stage for this order code is current production. That means it is still an active catalog item from Siemens, not a phase-out or NRND part. For a BOM line that calls out 3RV2021-1GA10-ZW97, the fit is confirmed by the Trip Class 10 and the 100 kA SCCR at 400 V — the two ratings that govern motor protection coordination. Sourced and quoted to order against an RFQ through independent distribution; availability and current pricing are confirmed at quote time.
Deployment context
This breaker lands in a motor feeder circuit inside a panel or enclosure, typically on a 35 mm DIN rail alongside a SIRIUS contactor and a control transformer. The 45 mm width and 97 mm depth fit the standard 60 mm deep enclosure profile — no need for a deep gland plate. The screw-type terminals on the main current circuit accept solid or stranded conductors up to 2×10 mm², which covers the wire range for most motor circuits up to the 5 hp rating at 575/600 V.