The Siemens 5SJ4106-8HG42 is a 1-pole miniature circuit breaker from the SENTRON 5SJ4 series, rated 6 A at 30 °C with a D tripping characteristic — built to handle high inrush currents from motor, transformer, or lighting loads without nuisance trips on startup.
The D-curve (tripping characteristic class D) means the magnetic trip triggers at 10–20× the rated current — so for a 6 A breaker, instantaneous trip happens between 60 A and 120 A. That's the right curve for loads like small motors, solenoid valves, or switch-mode power supplies where the inrush peak would otherwise pop a B or C curve. At 30 °C and 40 °C the full 6 A rating holds; above that it derates linearly to 5.4 A at 60 °C (–). The 60 V DC maximum rating covers control-circuit DC rails, though the primary application is AC branch-circuit protection. IP20 with connected conductors (IP40 in the handle area) is standard for enclosed distribution boards — no special sealing gaskets needed inside a cabinet.