What it is and what it does
The Siemens 3RV1021-1KA15-ZW96 is a SIRIUS motor protection circuit breaker designed for motor protection, with a continuous current rating of 12.5 A and a CLASS 10 trip characteristic. Rated for 5.5 kW at 400 V AC, it handles motor loads up to that power, with a maximum operating voltage of 690 V AC. It includes phase failure detection and an integrated auxiliary switch, making it suitable for three-phase motor circuits where loss-of-phase protection is required.
Key ratings and what they mean for fit
The 12.5 A continuous rating sets the maximum steady-state current the breaker can carry without tripping; size it to match the motor full-load current, not the starting surge. CLASS 10 trip characteristic protects motors with short starting times. Breaking capacity: 100 kA at 240 V and 400 V AC, 42 kA at 500 V, and 6 kA at 690 V. This tells you the maximum fault current it can safely interrupt at each voltage level — critical for verifying SCCR compliance with the upstream panel.
Mounting and integration
Mounts via screw and snap-on onto 35 mm standard DIN rail per DIN EN 50022. Dimensions: 45 mm wide, 97 mm high, 96 mm deep — fits a standard 45 mm module slot. Front protection is IP20; the enclosure is rated for any mounting position, with 0 mm clearance required at the sides and back. Terminals accept solid conductors: 2x (0.5–1.5 mm²) and 2x (0.75–2.5 mm²); stranded: 2x (1–2.5 mm²) and 2x (2.5–6 mm²). Screw-type terminals for the main current circuit.