What this MCCB delivers for your panel
The Siemens SENTRON 3VA1120-5ED32-0AA0-ZD00 is a 3-pole molded case circuit breaker on the IEC frame 160 platform, rated for 55 kA breaking capacity at 415 V AC — that is the class M interrupting rating, meaning it clears bolted faults up to that level without upstream fuses or a larger frame taking over. The thermal-magnetic release is a TM210, set fixed at 20 A (Ir = In) with a short-circuit pickup of 16× In, so it protects a 20 A feeder or load circuit against sustained overloads and instantaneous faults. The nut keeper kit variant (ZD00 suffix) is configured for DC Power OEM applications in China, with box terminals on both sides and front connection.
What the ratings mean for fit
The 55 kA @ 415 V breaking capacity (class M) is the key coordination number: it tells you this breaker can be applied downstream of a transformer or upstream feeder with a prospective fault current up to that level, and it will interrupt without welding contacts or venting arc gas into the enclosure. The TM210 release with Ii = 16 × In (320 A instantaneous pickup) is a line-protection curve — it is not a motor-protection or generator curve, so it is sized for cable and busbar protection, not for starting inrush. The 20 A fixed rating means no adjustment band; you order the exact amp rating the branch circuit needs.
Panel integration notes
The 3VA1 frame is a standard panel-mount MCCB — 76.2 mm wide, 130 mm tall, 70 mm deep — with front terminals and box lugs on both sides. It accepts stranded conductors up to 70 mm² per pole. The IP40 front protection is typical for enclosed distribution boards; no additional sealing is needed inside a rated panel. The nut keeper kit (ZD00) is a mechanical detail for the DC Power OEM variant — it retains the terminal nuts during assembly in high-vibration or high-throughput production.