The Siemens 5SJ4111-7HG42 is a SENTRON miniature circuit breaker, 1-pole with C-curve tripping characteristic, rated 10 kA breaking capacity per EN 60898 and 15 kA per IEC 60947-2 at 400 V AC. It also carries a DC rating of 60 V. This is the current-production version — lifecycle status is active, so it's a standard BOM line item, not a phase-out or NRND part.
The 10 kA (EN 60898) and 15 kA (IEC 60947-2) figures tell you the fault-clearing capability: EN 60898 is the household/commercial standard, while IEC 60947-2 is the industrial standard with higher interrupting duty. The 1-pole design (single modular width, 18 mm) fits standard DIN-rail enclosures and occupies one position in a lighting or sub-distribution panel. Mounting position is unrestricted, so it can go sideways or upside-down if panel space forces it. Rated insulation voltage (Ui) is 440 V AC, which means the internal clearance and creepage distances are designed for a 440 V system — fine for 400 V networks with normal voltage tolerance.