What this breaker is and what the ratings mean
The Siemens 3VA1020-2ED42-0AA0-ZD00 is a 4-pole IEC frame 100 molded case circuit breaker (MCCB) sized for line protection in distribution panels. Its 20 A fixed thermal overload (Ir=20 A) and fixed short-circuit pickup at 16× In (Ii=16 x In) make it a straight TM210 thermal-magnetic release — no adjustable trip unit, which simplifies spec-in for a fixed-load BOM line. Breaking capacity class B means Icu=16 kA at 415 V AC. That is the maximum fault current it can safely interrupt without damage. For a 20 A breaker feeding a motor control center or lighting panel downstream of a transformer, 16 kA SCCR at the secondary voltage is typical — but verify the available fault current at the point of installation. If the utility-side fault level exceeds 16 kA, this breaker needs an upstream current-limiting device to coordinate. The N conductor is unprotected on this variant, and the nut keeper kit is included for DC Power OEM builds in China. That last detail matters for procurement traceability: the -ZD00 suffix flags a specific OEM configuration, so a standard 3VA1020-2ED42-0AA0 will not ship with the same kit or documentation.
Where it fits in the panel
Mounts on a DIN rail or direct to the backplate via the frame 100 footprint. The 4-pole body takes up four module widths — plan the gland plate and busbar routing accordingly. No auxiliary contacts or shunt trip are included by default; if you need alarm signaling or remote trip, order the accessory kit separately.