What this breaker is and what the ratings mean
The Siemens 3VA1140-5EF32-0AA0-ZD00 is a 3-pole IEC molded-case circuit breaker in the 3VA1 series, built on a 160 A frame. Its headline rating is a breaking capacity class M with Icu = 55 kA at 415 V — that means it can safely interrupt a fault current up to 55,000 A at that voltage without welding contacts or rupturing the case, which is the spec that governs selectivity coordination in a distribution panel. The thermal-magnetic trip unit (TM240, ATAM) is set for line protection: overload protection Ir adjustable from 28 A to 40 A, and short-circuit protection Ii fixed at 5 to 10 times In (200–400 A). The nut keeper kit is included for the DC Power OEM variant destined for China.