What this breaker is and what the ratings mean
The Siemens 3VA1120-4GD42-0AA0-ZD00 is a 4-pole IEC frame 160 circuit breaker with breaking capacity class S, rated Icu=36kA at 415 V. That 36 kA interrupting rating means it can safely clear a fault up to that level on a 415 V system without upstream cascading — critical for panel coordination studies where the available fault current is known to be in that range. The thermal-magnetic trip unit (TM210) is set with a fixed overload Ir=20 A and a fixed short-circuit pickup Ii=16 x In (320 A), so it's a dedicated line-protection device for a 20 A circuit, not adjustable in the field.
Deployment context and integration
This breaker mounts on a DIN rail inside a standard industrial panel. The 4-pole configuration with 100% N conductor protection suits three-phase plus neutral distribution in IEC-based switchboards — common in OEM builds for machinery or sub-distribution boards. The included nut keeper kit is a detail for DC Power OEM applications in China, meaning the factory-assembled busbar connections stay torqued under vibration.