The Siemens 5SL4202-7CC is a SENTRON miniature circuit breaker (MCB) — 2-pole, C-curve, rated 2 A at 400 V AC with a 10 kA interrupting capacity tested to EN 60898.
Where it fits and how it mounts
It's 36 mm wide — that's 2 modular width units (MWUs) — so it occupies two adjacent slots in a consumer unit or sub-distribution panel. Mounting position is unrestricted — vertical, horizontal, upside-down — the thermal-magnetic trip works the same way.
At 400 V AC, the breaker can switch off a fault of up to 10 kA — that's the short-circuit capacity per EN 60898. Pollution degree 2 means it expects only non-conductive dirt; in a dusty or humid environment, keep it inside a sealed enclosure. The 1.2 W power loss per pole at rated current is the heat it dumps into the panel — for a 2-pole breaker, that's 2.4 W total, negligible for most enclosures but worth noting if you're packing a dense row of breakers.