Siemens SENTRON 5SQ2270-2YA10 — 2-pole MCB, C-curve, 10 A
The Siemens SENTRON 5SQ2270-2YA10 is a 2-pole miniature circuit breaker (MCB) with a C-curve trip characteristic, rated 10 A at 400 V AC, and a 3 kA breaking capacity per EN 60898. It occupies 2 modular width units (about 36 mm on a DIN rail) and installs 55 mm deep into the panel — a standard footprint for a 2-pole MCB in a distribution board or sub-panel.
At 40 °C it derates to 9.25 A, at 50 °C to 8.7 A, and at 60 °C to 8 A. If this breaker sits in a crowded enclosure with other heat sources, the 40 °C or 50 °C column is the one that governs the load it can actually carry — don't spec it for a full 10 A continuous in a warm panel without checking the derating curve.
The 55 mm installation depth leaves clearance for wiring ducts and busbar connections in a typical 100 mm deep enclosure.