Selective main MCB for infrastructure panels
The Siemens SENTRON 5SP3780-1 is a selective main miniature circuit breaker (SHU) for residential and infrastructure distribution boards. Rated at 80 A with a 25 kA breaking capacity at 400 V AC, it clears high-fault currents upstream while leaving downstream branch circuits untouched.
Class E selectivity and breaking capacity
Class E tripping characteristic means this breaker delays its trip under short-circuit conditions to let downstream MCBs clear first — essential for a main disconnector feeding sub-distribution. The 25 kA rated short-circuit capacity at 400 V AC (EN 60898) is well above the 4.5–10 kA range of standard SENTRON branch MCBs like the 5SL3340-7CC or 5SL4363-7, so it holds up under a panel-level fault without cascading upstream. Overvoltage category IV and pollution degree 3 suit it for utility-side installation where surge and contamination risk is higher than a clean indoor sub-panel.
Mechanical and environmental limits
Rated for -40 °C to 70 °C ambient, covering unheated utility rooms and outdoor-adjacent enclosures. Vibration resistance per IEC 60068-2-6 at 2 g over 5–150 Hz and shock resistance to 30 g (3 impacts, 11 ms duration) confirm it holds calibration under transport and seismic events. The 20 000 mechanical switching cycles typical service life is standard for a main breaker not cycled daily. IP20 with connected conductors — no washdown rating, so keep it inside the panel gland plate.
Panel fit and wiring
Occupies 6 modular width units on 35 mm DIN rail. Saddle terminals accept copper conductors; the pre-assembled adapter and locking caps reduce installation steps. Depth of 92 mm fits standard enclosures.