Siemens 5SL4108-8CC SENTRON MCB — 1-pole D-curve 8 A
The Siemens 5SL4108-8CC is a 1-pole miniature circuit breaker from the SENTRON series, with a D tripping characteristic rated at 8 A. It breaks fault currents up to 10 kA per EN 60898 at 230/400 V AC — the standard residential and light commercial interrupting rating. The D-curve means it tolerates the high inrush of motor and transformer loads without nuisance tripping, making it a fit for pump, compressor, or small-drive branch circuits where a C-curve would trip on startup.
What the ratings mean for your panel
Rated 8 A continuous, with a D-curve magnetic trip that holds through the 5–10× In surge typical of motor starts. The 10 kA breaking capacity per EN 60898 certifies it can safely interrupt a 10 kA prospective short-circuit current at 230/400 V — that is the standard for most residential and light commercial distribution boards. Single-pole design (1P) means it switches only the phase; the neutral is not broken. Rated for single-phase operation at 250 V AC and multi-phase at 440 V AC, so it covers both 230 V branch circuits and 400 V three-phase panels when used on one phase. The 18 mm width (1 modular unit) snaps onto standard DIN rail and occupies one slot in a distribution board. Depth of 76 mm and height of 90 mm keep it flush with adjacent devices. Mounting position is unrestricted — any orientation works. The IP20 rating (with connected conductors) is typical for enclosed panel use; no washdown or outdoor exposure without an outer enclosure. Rated for ambient temperatures from -40 °C to 75 °C, covering unheated enclosures in cold climates and warm cabinets near transformers. The 0.8 W power loss per pole at rated current is low enough to ignore for thermal budgeting in a populated board. Supplementary devices (auxiliary contacts, shunt trips, alarm switches) can be snapped onto the right side — the product extension feature is supported.