The Siemens 5SY4501-8CV is a 1P+N miniature circuit breaker rated for Icu=15kA at 230/400V, with a D1 tripping curve. The 1P+N configuration switches both the line and neutral, with overcurrent protection only on the line pole, common in single-phase distribution subcircuits where neutral isolation is required.
Snap-on DIN rail mount for standard TH35 profile. The 1P+N width is 2 modules (36 mm), so factor that into enclosure fill. Rated for 15 kA interrupting capacity at 230/400 V — this breaker can sit upstream of a subpanel without needing a current-limiting backup fuse in most residential and light commercial service entrances.