The 5SJ4115-8HG42: The D curve means it's built for loads with high inrush — think motor starters, transformers, or welding equipment. The magnetic trip is set to 10–20× rated current, so nuisance tripping on start-up is less likely than with a B or C curve.
Width is 18 mm (one modular unit), depth 70 mm, height 121 mm. The 70 mm installation depth matches most distribution boards — no panel depth surprises.
Overvoltage category 3, pollution degree 3 — suitable for fixed installations inside a panel where transient overvoltages and conductive dust are expected. IP20 with connected conductors, IP40 in the handle area.
Halogen-free and silicon-free construction, which matters in environments where outgassing could contaminate sensitive contacts or optics.