The Siemens SENTRON 5SL5440-7RC is a 4-pole miniature circuit breaker (MCB) with a C tripping characteristic, rated for 40 A on DC circuits up to 880 V. It carries a 10 kA breaking capacity per the description, sized for DC distribution in residential and infrastructure applications. The C-curve means it trips between 5 and 10 times rated current — suited for moderate inrush loads like lighting banks or small DC motor drives where you need some tolerance for starting current without nuisance trips.
DC rating and pole configuration
Rated for DC operation at 880 V maximum, this 4-pole breaker (4P design) handles series-connected poles to achieve that voltage rating — each pole shares the voltage drop, so the internal arc chambers are sized for the DC interruption duty. DC arcs don't self-extinguish at zero-crossing the way AC arcs do, so the 10 kA DC breaking capacity is a meaningful spec: it tells you the breaker can interrupt a fault current of that magnitude on a DC bus without welding contacts or venting plasma. The 4-module width (72 mm) and 70 mm installation depth fit standard SENTRON distribution boards.
Environmental and installation constraints
Rated for ambient temperatures from -40 °C to 75 °C, with pollution degree 2 and overvoltage category II — typical for fixed indoor installations where transient overvoltages are moderate. IP20 with connected conductors means it's protected against solid objects larger than 12 mm (fingers) but not against moisture; mount it inside a cabinet or enclosure, not in a wet location. Mounting position is unrestricted, which simplifies panel layout. The housing is halogen-free and silicon-free, relevant for environments where outgassing from a fault could contaminate sensitive contacts or optics.