The Siemens 5SY4620-8 is a SENTRON miniature circuit breaker in a 4-pole (3P+N) configuration, designed with a D tripping characteristic. It's rated for 400 V AC and 60 V DC, with a breaking capacity of 10 kA per EN 60898 and 20 kA per IEC 60947-2 — the higher IEC figure gives you headroom for fault-current coordination downstream of a transformer or in an industrial panel where the prospective short-circuit current exceeds the domestic standard. At DC, it handles 15 kA per IEC 60947-2, and 5 kA per UL 1077/CSA for North American acceptance.
What the ratings mean for fit
The D-curve (10-20x In) is built for high-inrush loads — motor starters, small transformers, welding equipment — where the startup surge would nuisance-trip a B or C curve. If your line feeds a contactor coil bank or a bank of LED drivers with capacitive input, this is the curve that stays in. The 4-pole design with neutral switching means it disconnects all live conductors, which is required for some machine safety circuits and TN-S systems where the neutral must be switched. The 20 kA SCCR under IEC 60947-2 is the number your panel designer cares about for selectivity — it means this breaker can interrupt a fault up to 20 kA without upstream devices needing to clear it. At 400 V AC, that covers most industrial distribution boards. The UL 1077 rating at 5 kA is supplementary protection for North American panels; it's not a branch-circuit rated breaker under UL 489, so know your local code. Mounts on a DIN rail via the quick-assembly system, any position. It occupies 4 modular width units (72 mm wide), with a depth of 76 mm and an installation depth of 70 mm. The IP20 rating (with connected conductors) is standard for enclosed panel use — no washdown rating, so keep it behind the gland plate.