The Siemens 3VA1120-5ED42-0AA0-ZD00 is a 4-pole IEC frame 160 molded case circuit breaker from the SENTRON 3VA1 series, built for line protection with a fixed thermal-magnetic TM210 trip unit. The headline number here is the 55 kA breaking capacity at 415 V — that's the Icu (ultimate short-circuit breaking capacity) under IEC 60947-2, meaning it can safely interrupt a fault current up to 55,000 A without welding its contacts or failing catastrophically. The 20 A fixed overload setting (Ir=20 A) and instantaneous pickup at 16 x In (Ii=16 x In) mean this breaker is set for a specific load — it's not field-adjustable for a different amp draw.
The included nut keeper kit is a small but practical detail for panel builders: it keeps the terminal hardware from wandering off during assembly, which saves time on the line. The 'for DC Power OEM in China' suffix on the order code indicates this variant was configured for a specific OEM application, so verify the termination and any special markings before committing to a panel layout.