What this MCB is and what it does
The Siemens SENTRON 5SL4108-7 is a 1-pole miniature circuit breaker rated 8 A with a C tripping characteristic, designed for AC circuits up to 400 V. It interrupts fault currents up to 10 kA per EN 60898 and IEC 60947-2, which means it safely clears a short-circuit up to that level without welding its contacts or cascading failure upstream in the distribution board. The C-curve (5–10× In magnetic trip) suits it for moderate inrush loads like small motor starters, lighting banks, and transformer primaries in residential and light commercial infrastructure panels.
Panel fit and mounting
Occupies 1 modular width unit (18 mm) on a DIN rail, with an installation depth of 70 mm and overall depth of 76 mm. Mountable in any position, which simplifies layout in crowded enclosures. Sealable terminals (padlockable) let the panel builder lock out the circuit for maintenance isolation. The IP20 rating with connected conductors means it's protected against finger contact but not washdown — standard for dry indoor distribution boards.
Environmental and compliance notes
Halogen-free and silicon-free construction, which matters for panels in environments sensitive to outgassing (e.g., clean rooms, medical equipment, or sealed enclosures near sensitive electronics). Rated for pollution degree 2 and overvoltage category III, so it's suitable for fixed-installation distribution boards downstream of the utility meter. Mechanical service life of 10 000 operating cycles typical.