The Siemens 3VA1112-4EE42-0AA0-ZD00 is a 4-pole IEC frame 160 circuit breaker in the 3VA1 series, rated for line protection with a TM220 thermal-magnetic trip unit (ATFM). Its interrupting capacity is Icu=36kA at 415V, placing it in breaking capacity class S — sufficient for most industrial distribution panels where fault levels stay under that threshold. The continuous current rating In=125A, with overload protection adjustable Ir=88A...125A and fixed short-circuit protection Ii=10 x In.
What the ratings mean for fit
The 36kA breaking capacity at 415V is the key selectivity figure: it tells you this breaker can safely interrupt a fault up to that level without upstream devices needing to clear it. The adjustable Ir band (88–125A) lets you fine-tune the overload pickup to match the actual load current, which is useful when the connected load is below the fixed In. The fixed Ii=10 x In means instantaneous magnetic trip occurs at 1250A — typical for motor-starting inrush protection on a line-protection breaker. The N conductor is unprotected, which is standard for 3-phase + N systems where the neutral is not expected to carry fault current.
Deployment context
This breaker mounts on a standard DIN rail inside an enclosure, with the nut keeper kit included for secure DC Power OEM installations in China. The 4-pole configuration covers three-phase plus neutral, suitable for main incoming or feeder protection in distribution boards.