What this SIRIUS breaker does on the line
The Siemens 3RV1021-1CA10-ZX95 is a SIRIUS motor protection circuit breaker rated for 2.5 A continuous current with a CLASS 10 trip curve, meaning it clears overloads fast enough to protect standard induction motors during start-up without nuisance tripping on inrush. It carries 100 kA breaking capacity at 400 V AC (also at 240 V and 500 V), dropping to 8 kA at 690 V — that's the short-circuit current it can safely interrupt without welding contacts or cascading failure upstream. Phase failure detection is built in, so a lost leg on a three-phase motor triggers a trip rather than letting the motor single-phase and burn. The auxiliary switch contact is included on the device — no separate add-on module needed for status feedback to the PLC or annunciator.
Mounting and panel fit
Mounts via screw or snap-on onto 35 mm DIN rail per EN 50022, with zero clearance required at the sides or rear — so it packs tight in a crowded enclosure. The front face carries IP20 protection, standard for a panel-mounted device — no special sealing needed for dry indoor cabinets. Dimensions are 45 mm wide, 97 mm tall, 96 mm deep — fits the standard SIRIUS 45 mm footprint, same as the 3RV1011 frame.
Wiring and termination
Main circuit terminals are screw-type, accepting solid or stranded copper: 2x (1 … 2.5 mm²) or 2x (2.5 … 6 mm²) per clamp, with AWG equivalents of 2x (14 … 10).