What this MCCB carries — and where it stops
The Siemens 3VA1020-4ED36-0KH0 is a SENTRON 3-pole molded case circuit breaker rated for 20 A continuous current (Iu) with a TM210 thermal-magnetic overcurrent release. Its breaking capacity hits 121 kA at 240 V AC, 75.6 kA at 415 V, 52.5 kA at 440 V, and 11.9 kA at 690 V — so the interrupting rating drops fast as line voltage climbs; at 690 V it's still a solid 11.9 kA, but don't spec it for high-voltage high-fault panels without checking the curve.
Thermal derating — the real current limit
The breaker holds 20 A from 40 °C up to 50 °C ambient. At 55 °C it derates to 19.2 A, at 60 °C to 18.8 A, at 65 °C to 18.4 A, and at 70 °C to 18 A. If the panel runs hot — say a crowded enclosure near a drive cabinet — that 20 A nameplate becomes 18 A. The operating range spans -25 °C to 70 °C; storage goes -40 °C to 80 °C.
Panel fit and auxiliary wiring
Footprint: 70 mm deep, 76.2 mm wide, 130 mm tall. That 76.2 mm width is three standard 25.4 mm pole pitches — it'll drop into a 3-pole MCCB slot on a DIN rail or panel-mount base without surprises. The auxiliary contact block ships as 2 auxiliary switches plus 1 trip alarm switch (HQ configuration). A shunt trip (STL) is built in; the integrated auxiliary trip uses a separate order code 3VA9688-0BL33 for the release module itself. Front-face protection is IP40 — fine for a clean panel, not for washdown.