Selective MCB for upstream feeder protection
The Siemens 5SP3780 is a SENTRON selective miniature circuit breaker (SHU), 1-pole rated at 80 A with a 25 kA breaking capacity per EN 60898. The E tripping characteristic means it's designed for selective coordination — it holds in during downstream short-circuits so only the faulted branch clears, keeping the rest of the distribution live. This is the main breaker for a residential or infrastructure sub-distribution board, not a branch device. Rated 230 V AC at 50 Hz, with an insulation voltage of 690 V and surge voltage resistance of 6 kV (overvoltage category IV, pollution degree 3). The 80 A rating and 25 kA SCCR make it suitable for high-fault utility entrance or riser applications where a standard MCB would trip on through-fault.
Mounts on a standard 35-mm DIN rail (EN 60715) or via busbar/screw mounting with accessories. Occupies 2 modular width units (MW) — 36 mm of rail space. Depth is 91 mm (92 mm with enclosure), height 145 mm. The sealable design allows the panel builder to lock the setting after commissioning. Saddle terminals accept standard copper conductors. The switch position indicator shows green for OFF, red for ON — a quick visual for the wireman during panel checkout.
Mechanical service life is 20 000 switching cycles typical. Shock resistance is 30 g for at least 3 impacts at 11 ms duration; vibration resistance per IEC 60068-2-6 is 2 g over 20 frequency cycles from 5 to 150 Hz. These ratings confirm suitability for transport and installation in commercial building infrastructure, not heavy industrial vibration.