What it is and what the ratings mean
The Siemens 5SY7110-6KK13 is a SENTRON miniature circuit breaker — 1 pole, 10 A rated current at 35 °C, B tripping characteristic. B-curve means it trips between 3 and 5 times rated current, so it's the right choice for resistive and general-purpose loads where you don't want nuisance trips from small inrush spikes. Breaking capacity is 25 kA per EN 60898 and 30 kA per IEC 60947-2 — that's the fault current it can safely interrupt without welding contacts or bursting the case. At 400 V line-to-line that covers most industrial panel secondary faults.
Thermal derating matters in a warm panel
The 10 A rating is at 35 °C ambient. Inside a crowded enclosure at 50 °C the breaker is good for 8.74 A; at 60 °C it drops to 8.04 A. If you're loading a branch near the nominal rating, check the actual panel ambient — the 5SY7 series derates linearly above 35 °C. That's not a datasheet footnote; it's the difference between a circuit that holds and one that nuisance-trips on a hot afternoon.
Fit and mounting
Single modular width (18 mm) snaps onto DIN rail via the quick-assembly system. Depth is 76 mm, installation depth 70 mm — fits standard distribution boards and sub-panels without a deep enclosure. IP20 with conductors connected; pollution degree 3, overvoltage category III. Sealable and touch-protected, so it's suitable for meter cabinets or utility compartments where sealing is required.