What this breaker is
The Siemens 3VA1140-5GE42-0AA0-ZD00 is a 4-pole IEC molded case circuit breaker in the 3VA1 family, frame 160, with a 40 A thermal-magnetic trip unit (TM220, ATFM). Overload protection is adjustable from 28 A to 40 A; short-circuit protection is fixed at 10 x In (400 A). The N conductor is protected at 100%.
The 55 kA Icu at 415 V is a high-interrupting rating for a frame-160 breaker — it handles substantial fault energy, which matters when coordinating with upstream transformers or large motor starters. The adjustable Ir (28–40 A) lets you fine-tune the overload setting to match the connected load, avoiding nuisance trips on inrush while still protecting the cable. The fixed Ii at 10 x In is a magnetic-only short-circuit pickup; it's not adjustable, so verify your load's inrush won't exceed 400 A peak.