What this 20 A MCCB brings to a panel
The Siemens SENTRON 3VA1020-2ED36-0HA0 is a 3-pole molded case circuit breaker rated for 20 A continuous current. It carries a 52.5 kA interrupting rating at 240 V, 32 kA at 415 V, and 13.6 kA at 440 V — numbers that tell you it handles serious fault current without needing an upstream fuse for most industrial panels. The TM210 thermal-magnetic release handles the overload and short-circuit protection. A built-in shunt trip (STL) gives you remote trip capability, which matters when you're tying the breaker into an E-stop string or a safety circuit.
Thermal derating you need to know
This breaker holds its full 20 A rating up to 50 °C ambient. Above that it starts to step down: 19.2 A at 55 °C, 18.8 A at 60 °C, 18.4 A at 65 °C, and 18 A at 70 °C. If your panel runs hot — say near a drive stack or a transformer — that derating curve is the one that decides whether the breaker holds or nuisance-trips. The operating range goes from -25 °C to 70 °C, with storage from -40 °C to 80 °C.
What fits and what doesn't
The 3VA1020-2ED36-0HA0 measures 70 mm deep, 76.2 mm wide, and 130 mm high — a standard SENTRON compact footprint that drops into most DIN-rail or panel-mount MCCB layouts. No auxiliary contacts, no communication module, no undervoltage release on this variant. The front is IP40 rated, so it's fine for a clean indoor panel but not for washdown areas. The shunt trip accessory is order code 3VA9688-0BL30 if you need a spare or a separate part number for the BOM.