SENTRON 5SP3732-1 selective MCB — 32 A, 25 kA, E characteristic
The Siemens 5SP3732-1 is a SENTRON 5SP3 series selective miniature circuit breaker (MCB) rated 32 A at 400 V AC, 50 Hz, with a 25 kA breaking capacity per EN 60898. The E tripping characteristic means it's designed for selectivity — it delays tripping on high inrush currents so that downstream MCBs clear the fault first, keeping this breaker closed and the rest of the distribution board live.
Rated 32 A continuous at 400 V AC — sized for a main incomer or sub-feed in a residential or infrastructure distribution board, not for final branch circuits. The 25 kA breaking capacity (Icn) per EN 60898 means it can handle high prospective fault currents typical at the service entrance. Overvoltage category IV confirms it's rated for the utility-side of the installation, not just downstream equipment. The E characteristic is the key differentiator: it's a selective (time-delayed) trip curve that coordinates with downstream MCBs so only the faulted circuit opens. That's the whole point of the 5SP3 series — you use it as the main breaker in a selective distribution scheme. Conductor cross-section range is 2.5 mm² minimum to 50 mm² maximum, with saddle terminals. That 50 mm² top end is generous for a 32 A breaker — it lets you land the incoming feeder cable without a separate terminal adapter. The 3-pole construction (3P) with 6 width units means it occupies six 18 mm module positions on the DIN rail — plan for that footprint in the distribution board layout.
Where it's used — selective distribution
This is a main miniature circuit breaker (SHU — Selective Hauptsicherungsautomat) designed for the incoming supply position in residential buildings and infrastructure installations. The selective trip characteristic ensures that when a downstream MCB trips on a fault, this main breaker stays closed — keeping power to the rest of the board. That's critical for lighting, common areas, and essential circuits in apartment blocks, schools, or small commercial buildings where you don't want a single fault killing the whole supply.