The Siemens SIRIUS 3RV1021-0JA38-1KT0 is a motor protection circuit breaker designed for 1 A continuous current with CLASS 10 trip characteristics, meaning it trips within 10 seconds at 7.2× the thermal setting — standard for protecting standard induction motors during start-up. It mounts via screw or snap-on onto 35 mm DIN rail per EN 50022, takes any mounting position, and measures 45 mm wide by 97 mm high by 96 mm deep. The main circuit uses screw-type terminals accepting 2x (0.25... 2.5 mm²) solid or 2x (24... 14) AWG; the auxiliary and control circuit uses spring-loaded terminals.
Breaking capacity and duty
This breaker delivers 100 kA breaking capacity across the board — at 240 V, 400 V, 500 V, and 690 V AC — so it handles high-fault industrial panels without cascading upstream. The AC-3 motor-switching rating maxes out at 690 V, and at 400 V it's rated for 0.25 kW motor load. Maximum operating frequency in AC-3 duty is 15 operations per hour.
Auxiliary switch and environmental ratings
The auxiliary switch is transverse design and field-addable (product extension auxiliary switch is yes). Switching capacity: 1 A at 24 V, 0.15 A at 60 V, 0.5 A at 230 V. Surge voltage resistance is 6 000 V. Shock resistance is 25 g for 11 ms. Front protection class is IP20 — suitable for enclosed panels, not for washdown environments.