What this 100 A C-curve MCB does on the rail
The Siemens SENTRON 5SP5191-7 is a 1-pole miniature circuit breaker rated 100 A with a C tripping characteristic, designed for standard mounting rail and screw fixing in distribution panels. It handles AC supplies up to 440 V and DC circuits up to 250 V, with a DC breaking capacity of 10 kA per EN 60898-2 and an AC breaking capacity of 3 kA per EN 60898. The 100 A rating and C-curve (5–10× In magnetic trip) make it a fit for high-current branch circuits feeding resistive or moderate inductive loads — think large contactor coils, lighting banks, or sub-distribution feeds — where the inrush won't nuisance-trip a B-curve but you don't need the higher magnetic threshold of a D-curve.
Wire range and terminal design — panel-builder detail
Both top and bottom tunnel terminals accept solid or stranded conductors from 4 mm² up to 50 mm², which covers the full range for a 100 A feed without needing a separate reducer or ferrule adapter. The 27 mm width (1.5 width units) and 70 mm installation depth keep the panel fill factor tight — you can land a 50 mm² cable in a standard 18 mm DIN-rail pitch without crowding the adjacent breakers. The housing is halogen-free and silicon-free, which matters if the panel sits in a clean-room or food-production environment where outgassing could contaminate product or optics.
Environmental and mounting flexibility
Rated for ambient temperatures from -25 °C to +55 °C and storage from -40 °C to +75 °C, with up to 95 % humidity. Mounting position is any, and the supply connection can enter from any direction — no derating needed for upside-down or horizontal rail orientation. The IP20 protection class (with connected conductors) is standard for enclosed distribution boards; the sealable housing and touch-protection feature support lockout/tagout procedures during maintenance.