The Siemens 5SP5280-7 is a 2-pole SENTRON miniature circuit breaker rated for 80 A with a C tripping characteristic. It breaks faults at 10 kA DC (EN 60898-2) and 15 kA DC (IEC 60947-2), plus 3 kA AC at 400 V. The C-curve means it tolerates moderate inrush — think motor starts or capacitor banks — without nuisance tripping, while still clearing overloads fast enough for branch-circuit protection.
What the ratings mean for fit
At 80 A and 2 poles, this breaker handles a single-phase 80 A load or splits across two poles for a 2-pole 80 A feed. The C-curve (5–10x In magnetic trip) suits mixed loads with some motor or transformer inrush — a pump or small compressor on a 400 V line. The 3 kA AC SCCR at 400 V is the standard residential/light-commercial fault level per EN 60898; the 15 kA DC rating per IEC 60947-2 covers tougher industrial DC bus protection. For a panel fed from a 400 V transformer with a 3 kA prospective fault current, this breaker coordinates cleanly downstream. Mounts on standard DIN rail or screw fixing — any orientation, any position of the supply cord. The 54 mm width (3 width units) and 76 mm depth fit a standard 4-module enclosure. IP20 with conductors connected; pollution degree 3 and overvoltage category 3 mean it's rated for the usual industrial panel environment, not sealed outdoor duty.
Lifecycle and sourcing reality
The SENTRON 5SP5 series is the current-generation miniature breaker family from Siemens, replacing older 5SL and 5SQ lines. If your panel was built around a 5SL4363-7 or 5SQ2370-2YA01, the 5SP5280-7 is the functional successor — same 2-pole C-curve footprint, same DIN-rail mount, higher DC breaking capacity. Drop-in check: the 54 mm width and 76 mm depth match the standard 3-MU slot, so no rewiring or enclosure mods needed.