It's built for overcurrent protection in control panels and distribution boards — the kind of line-side or branch-circuit protection you'd spec into a machine or a sub-panel. The 15 A rating holds at 30 °C and 40 °C ambient; derate slightly above that — 14.6 A at 45 °C, 14.1 A at 50 °C, 13.6 A at 55 °C, 13.2 A at 60 °C. If your panel runs warm, factor that in.
Depth is 70 mm, installation depth the same — no extra clearance needed behind the rail. Height is 121 mm. That's a standard MCB footprint; it'll drop into any SENTRON or third-party distribution board that accepts 18 mm-wide modules. IP20 with conductors connected, IP40 in the handle area — fine for enclosed panels.
If you're filling a BOM line or replacing a failed unit in a panel, the 5SJ4118-8HG42 is a direct drop-in for any 1-pole, 15 A MCB application using the same DIN-rail footprint. No rewiring or panel modification needed.