The Siemens 5SY5280-6CC is a 2-pole miniature circuit breaker from the SENTRON series, designed for DC circuits up to 440 V. Its B tripping characteristic means it trips at 3 to 5 times rated current — suited for resistive or general-purpose loads where inrush is low, not for motor starting. At 35 °C ambient it carries 80 A; derate to 76 A at 40 °C, 73.92 A at 45 °C, 71.84 A at 50 °C, and 69.6 A at 55 °C — the thermal curve is published, so panel builders can size for elevated enclosure temperatures without guessing.
DC breaking capacity and installation
Rated DC breaking capacity is 10 kA per IEC 60947-2 at 440 V DC — that is the fault current it can safely interrupt on a DC bus. Overvoltage category III and pollution degree 3 mean it is rated for fixed installations inside industrial panels, not for outdoor or wet locations. IP20 with connected conductors; the enclosure itself is finger-safe only when wired. Mounts in any position via the quick-assembly system (snap-on DIN rail), occupies 2 modular width units (36 mm wide). Depth is 76 mm, installation depth 70 mm — confirm clearance behind the rail before wiring.