Siemens 5SY4532-8 SENTRON MCB — 32 A, D Curve, Dual-Rated Breaking Capacity
That 20 kA figure at 400 V gives you selectivity headroom downstream of a 25 kA-rated main breaker in most distribution boards. DC rating is 15 kA per IEC 60947-2, useful for battery banks or DC bus protection. Temperature derating is published: 32 A at 35 °C, 30.46 A at 40 °C, 28 A at 55 °C, 27.14 A at 60 °C. If your panel ambient runs above 40 °C, size the load at the derated figure — the thermal-magnetic element tracks ambient, so a 30 A continuous load in a 50 °C cabinet is fine, but pushing 32 A at 60 °C will trip on the thermal curve.
Installation depth is 70 mm. Combined terminal top and bottom — line and load can land on either side, which saves a wiring reversal if the busbar arrangement changes. Suitable for mechanical engineering and industrial environments per the manufacturer's classification.
Standards compliance covers IEC/EN 60898-1 (household-type MCB) and IEC/EN 60947-2 plus UL1077 (industrial supplementary protector). That dual listing lets the same part serve both a UL 508A industrial panel and an IEC distribution board — one SKU for both sides of the shop.