The Siemens 3VA1112-4GD42-0AA0-ZD00 is a 4-pole IEC frame 160 circuit breaker from the 3VA1 line, rated for 125 A with a fixed thermal-magnetic trip unit (TM210). Its breaking capacity hits 36 kA at 415 V — class S, which means it handles high fault currents common in industrial distribution panels without needing an upstream current-limiting fuse. The fixed Ir=125 A and Ii=10 x In (1250 A short-circuit pickup) make this a straight-in replacement for a line-protection breaker where you don't need adjustable overloads. It also carries 100% neutral conductor protection and includes a nut keeper kit, specified here for a DC Power OEM in China.
What the ratings mean for fit
The 36 kA Icu at 415 V tells you this breaker can safely interrupt a fault up to that level without welding its contacts or blowing apart — critical for panel SCCR compliance under IEC 60947-2. The fixed thermal-magnetic trip (TM210) means no dials to mis-set; overload protection is locked at 125 A, and the magnetic short-circuit pickup is fixed at 10 times In (1250 A). That 10x multiplier is typical for motor-starting inrush on a distribution feeder, but verify it doesn't nuisance-trip on your specific load's starting current. The 100% N-conductor protection means the neutral pole is fully rated, not reduced — important for single-phase line-to-neutral faults on a 4-wire system. And the nut keeper kit is a small but real time-saver on the assembly line: no loose hardware rattling in the panel.