What it is and what it does
The Siemens SENTRON 5SY4508-7 is a 1P+N miniature circuit breaker with a C tripping characteristic, designed for branch-circuit protection in industrial control panels and distribution boards. It switches the neutral conductor and occupies 2 modular width units (36 mm) on a DIN rail. The C curve means it trips between 5 and 10 times rated current — the standard choice for moderate inrush loads like small motors, contactors, and lighting banks where you need selectivity against nuisance trips.
Breaking capacity — what the ratings mean
This breaker carries two breaking-capacity ratings because it's certified under both product and industrial standards. Per EN 60898 (the household / commercial standard) it's rated 10 kA at 230 V AC. Per IEC 60947-2 (the industrial standard for panel builders) it's rated 20 kA at 230 V AC, and 15 kA at 60 V DC. For UL 1077 / CSA C22.2 No. 235 applications it's rated 5 kA. The 20 kA figure is the one that matters for most industrial panels — it tells you this breaker can safely interrupt a fault up to 20 kA without welding its contacts or rupturing the case, which is enough for most secondary distribution boards fed by a transformer of 500 kVA or less.
Where it fits — panel integration
Mounts on a DIN rail via the quick assembly system in any position. Depth is 76 mm, installation depth 70 mm. IP20 with conductors connected.