The 10 kA breaking capacity per EN 60898 covers domestic and light commercial branch circuits; the 20 kA per IEC 60947-2 is the figure that matters for industrial panel SCCR coordination — it tells you the breaker can safely interrupt a fault up to 20 kA at 400 V without welding or cascading upstream. Derating is built into the datasheet: at 40 °C the rating drops to 19.04 A, at 50 °C to 18.04 A, and at 60 °C to 16.96 A.
Three modular width units (each 18 mm) means it occupies 54 mm of rail space — standard for a 3-pole MCB.
What to verify on receipt
The design is for railway applications (per) — that means it carries vibration and temperature cycling margins beyond a standard commercial MCB. On incoming inspection, check the nameplate matches: 3-pole, C-20 A, 10/20 kA, Siemens SENTRON branding. Halogen-free and silicon-free construction is stated, which matters for clean-room or high-reliability environments where outgassing can contaminate contacts or optics.