What the ratings mean for fit
The 3VA1112-5GD42-0AA0-ZD00 is a Siemens 3VA1 IEC frame 160 molded-case circuit breaker with a 125 A fixed thermal-magnetic trip (TM210) and a making/breaking capacity of 55 kA at 415 V AC — class M. That 55 kA Icu means it can safely interrupt a fault current up to that level without welding or rupturing, which is the figure you check against the available fault current at the panelboard. The 4-pole construction with 100% N-conductor protection (full-rated neutral) makes it suited for four-wire systems where the neutral carries load current, common in commercial and light-industrial distribution.
Deployment context
Mounts on a standard DIN rail or panel-mount base in a distribution board or motor control center. The nut keeper kit included (for DC Power OEM in China) simplifies bus-bar installation in DC applications, though the breaker itself is rated for AC distribution.