The Siemens 5SJ4108-7HG41 is a SENTRON 5SJ4 miniature circuit breaker, 1-pole, C-curve, rated 8 A at 400 V AC. It snaps onto a standard mounting rail and occupies one modular width (18 mm). The C-curve tripping characteristic means it handles moderate inrush — typical for motor starters, contactor coils, and general industrial loads — without nuisance trips, while still clearing short circuits fast enough for branch protection.
The 5SJ4108-7HG41 carries an IP20 rating on the body (IP40 in the handle area), which is standard for panel-mounted breakers — it's not intended for washdown or outdoor exposure. Vibration resistance is 50 m/s² at 25 to 150 Hz and 60 m/s² at 35 Hz (4 s), so it holds up on machinery with moderate vibration. The DC rating maxes out at 60 V — useful for control circuits but not for high-voltage DC bus protection.