The Siemens 5SP3850-2 is a SENTRON main miniature circuit breaker — 3-pole, rated 50 A at 30 °C, with a 25 kA breaking capacity per EN 60898. The tripping characteristic E means it's designed for selective coordination — it holds longer on overload than a standard B or C curve, so a downstream fault clears before this breaker trips, keeping power on to the rest of the panel. Rated 400 V AC (insulation voltage 690 V, overvoltage category IV, pollution degree 3) — this is a main breaker for residential and infrastructure panels, not a branch device. The 50 A rating at 30 °C derates to 47.5 A at 40 °C, 46.25 A at 45 °C, 45 A at 50 °C, and 43.75 A at 55 °C; if the panel ambient runs warm, size the load accordingly.
Mounts on busbar, occupies 4.5 modular width units. Depth is 89.5 mm, enclosure depth 76.3 mm, height 151.3 mm. Conductor cross-section accepts 2.5 to 50 mm² solid or stranded. IP40 with connected conductors.
Sealable (locking slide with lock, additional wire seal, cable ties and Antilux) — utility or inspector can lock the breaker in the off position, preventing unauthorized reclosure. Shock resistance: 30 g, at least 3 impacts, 11 ms duration — survives mechanical shock from door slams or nearby contactors without nuisance tripping. Surge voltage resistance rated 6 kV, appropriate for overvoltage category IV (mains-level transients).