The Siemens 5SP3732 is a SENTRON 5SP3 series main miniature circuit breaker — selective type (SHU), 1-pole, rated 32 A at 230 V AC, 50 Hz. The E tripping characteristic means it's designed for selective coordination downstream of a larger upstream device, holding through short-duration faults to keep the rest of the panel live. The 25 kA breaking capacity per EN 60898 is the headline number: it safely interrupts a 25 kA prospective fault current at 230 V without welding or arcing over, which is high for a 1-pole MCB — this is the part you spec when the available fault current at the panel is serious, not a residential load center.
Selectivity and coordination
The E curve is the key differentiator from a standard B or C curve. It has a wider magnetic trip band, so it tolerates higher inrush without nuisance tripping — exactly what you need when this MCB feeds a sub-distribution board or a motor starter with a soft-start. The 25 kA SCCR at 230 V AC means you can place it on a supply with up to 25 kA available fault current and still maintain the selective chain. For comparison, a standard 5SL series MCB with C-curve at 32 A typically breaks 6 kA or 10 kA; the 5SP3732's 25 kA is a full grade up in fault-handling capability.
Terminals accept solid conductors 2.5 to 50 mm² and stranded 2.5 to 70 mm², which is generous for a 32 A breaker; you can land a 35 mm² feeder without pigtailing. Saddle terminals are included — no need for separate ferrule or pin terminal on the stranded side. Depth is 76.3 mm, enclosure depth 92 mm; leaves about 16 mm behind the front panel for wiring clearance.