What this MCB is and where it fits
The Siemens 5SY5110-7KK11 is a 1-pole miniature circuit breaker from the SENTRON family, rated 10 A with a C tripping characteristic and a 10 kA breaking capacity per EN 60898. It occupies one modular width unit (18 mm) on a DIN rail, with a quick assembly system and any mounting position. The C-curve (tripping between 5 and 10 times rated current) makes it suitable for moderate inrush loads — think motor starters, small transformers, or lighting banks — where the magnetic trip needs to ride out the start surge without nuisance opening.
Key ratings and what they mean for your panel
Rated 10 A at 35 °C ambient, the breaker derates to 9.39 A at 40 °C and drops to 8.04 A at 60 °C — a thermal curve you need to account for when packing the enclosure. At 220 V DC it carries a 10 kA breaking capacity per EN 60898-2, so it handles DC control circuits and railway auxiliary supplies. The overvoltage category III and pollution degree 3 rating mean it's designed for fixed installations inside a panel, not for outdoor or wet locations. Touch protection (IP20 with connected conductors) is standard for the DIN-rail environment.