The 3 kA breaking capacity per EN 60898 tells you it safely interrupts a fault up to 3,000 A at 400 V AC. This breaker switches both poles (2-pole, switched neutral per). It accepts AC or DC supply voltage, though the 3 kA rating is specific to AC per EN 60898.
Panel integration
The 2 width units (36 mm) and 55 mm depth leave room alongside other SENTRON modules in a standard enclosure. Neutral conductor switching is built in, so no separate neutral bar needed downstream of this breaker in a 2-wire circuit.