4-pole C-curve MCB for distribution boards
The Siemens 5SN4432-7CN is a SENTRON miniature circuit breaker with four protected poles, a C tripping characteristic, and a 32 A rated current. It breaks fault currents up to 10 kA per EN 60898, which covers the majority of residential and light commercial distribution board applications where the prospective short-circuit current at the panel doesn't exceed that level. Rated for 400 V AC multi-phase operation, with a maximum of 440 V AC, this 4-pole unit handles three-phase loads plus a switched neutral — though the neutral conductor is not switched internally on this variant (the neutral pole is protected but not isolated).
DIN-rail fit and panel integration
Occupies 4 modular width units (72 mm) on a standard DIN rail. Depth of 76 mm and installation depth of 70 mm mean it sits flush with other SENTRON 5SN series breakers — no extra clearance needed behind the rail. Mounting position is unrestricted, so it can go sideways or upside-down in a tight enclosure without derating. Terminals accept solid conductors up to 25 mm², which is generous for a 32 A breaker — useful when back-feeding or looping through multiple breakers on a busbar. The IP20 rating applies only with conductors connected; the front is touch-protected per the product feature.
C-curve tripping and thermal behaviour
C-curve means the magnetic trip fires at 5 to 10 times rated current (160–320 A for this 32 A unit). That's the standard choice for general-purpose loads with moderate inrush — lighting banks, small motor circuits, control transformers. The thermal element handles sustained overloads; power loss per pole is 2.6 W in hot operating state at rated current, so four poles dissipate about 10.4 W total inside the enclosure. Ambient temperature range is -40 °C to +75 °C, with derating above 55 °C (the spec notes 55 °C at 95% humidity as the upper limit for full rating). Pollution degree 2 and overvoltage category III are standard for fixed-installation distribution boards.