What this breaker does on your line
The Siemens 3VA1340-6GE42-0AA0-ZD00 is a 4-pole IEC frame 400 molded-case circuit breaker rated 400 A continuous, with a 70 kA interrupting capacity at 415 V (breaking capacity class H). Overload protection is handled by the TM220 thermal-magnetic trip unit, adjustable from 280 A to 400 A (Ir). Short-circuit pickup is fixed at 10 x In (4000 A). The N-conductor protection is set at 100%, so the neutral pole tracks the phase poles — common for four-wire systems where the neutral carries unbalanced load.
The variant includes a nut keeper kit and is built for a DC Power OEM in China — that's a factory-configured option, not a field-add kit. If you're matching a BOM line, verify the OEM-specific packaging matches your incoming inspection process; the breaker itself is standard Siemens 3VA1 hardware.
The 4-pole frame takes up four module widths (roughly 280 mm across the face). For a 400 A feeder, plan for cable entry clearance — the line and load lugs accept conductors sized for the full 400 A rating, so leave bending space below the breaker.