This Siemens 3VA1140-3EE42-0AA0-ZD00 is a 4-pole IEC frame 160 molded case circuit breaker with a 40 A continuous rating and a 25 kA interrupting capacity at 415 V. The breaking capacity class N puts it in the standard-duty range for general distribution panels — not the high-fault gear you'd spec for a transformer secondary, but plenty for most branch circuits in a commercial or light industrial plant. The thermal-magnetic trip unit (TM220, ATFM) provides adjustable overload protection from 28 A to 40 A via the Ir dial, and fixed short-circuit protection at 10 times the In rating. The N conductor is unprotected on this variant, meaning the neutral bar passes straight through without a pole or trip. That's common for 3-phase + N distribution where the neutral only carries unbalanced current and doesn't need its own overcurrent device. The nut keeper kit is a detail for the DC Power OEM build in China — keeps the terminals from backing off under vibration on a DC bus.
The 4-pole footprint takes up the same width as four single-pole breakers ganged together, so factor that into your enclosure fill calculations. The nut keeper kit is already on the terminals, which saves a step if you're torquing down DC bus bars. The TM220 thermal unit is ambient-compensated, but if your panel runs above 40 °C ambient, you'll want to derate the Ir setting per the standard IEC 60947-2 thermal curve. In a crowded enclosure with drives or transformers dumping heat, that's a real consideration — the breaker might trip earlier than the dial setting suggests.