The Siemens 5SY4350-6 is a 3-pole SENTRON miniature circuit breaker with a B tripping characteristic, rated for 400 V AC and 60 V DC. It carries dual breaking capacities: 10 kA per IEC/EN 60898-1 and 15 kA per IEC 60947-2, with an additional 5 kA rating under UL 1077 and CSA C22.2 No.235. That means it can serve both residential-style distribution boards (EN 60898) and industrial panel applications requiring higher fault current withstand (IEC 60947-2) — useful when the same breaker needs to satisfy both a local code and a machine-level SCCR study. The B-curve trips between 3 and 5 times rated current, making it a good fit for resistive or general-purpose loads where inrush is modest — lighting circuits, control transformers, or small heater banks. It is not intended for motor starting or high-inrush transformer primaries; that would call for a C or D curve. This breaker snaps onto a standard DIN rail via its quick assembly system and occupies 3 modular width units (54 mm). It can be mounted in any position, which simplifies layout in tight enclosures. The IP20 rating applies with connected conductors, so it is suited for enclosed distribution boards or control panels — not for wet or washdown areas.
Lifecycle and sourcing
Compliance documentation is standard for the SENTRON series: the breaker is certified to IEC/EN 60898-1 and IEC 60947-2, plus UL 1077 and CSA C22.2 No.235. It is halogen-free and silicon-free, which matters for environments with strict outgassing requirements — clean rooms, medical equipment, or sealed enclosures where corrosive off-gassing could damage contacts.
Integration notes
Installation depth is 70 mm; overall depth including terminals is 76 mm. The combined terminal design (top and bottom) accepts both busbar and cable entry without needing separate adapters. Neutral conductor switching is not provided — this is a 3-pole breaker for line-only protection; a separate neutral bar or 4-pole variant is needed if neutral isolation is required. The breaker is rated for pollution degree 3 and overvoltage category III, so it is suitable for fixed installations within building distribution or industrial control panels where transient overvoltages up to 4 kV (typical for category III) can occur. The sealable feature allows the toggle to be locked in the off position for lockout/tagout compliance. Temperature derating applies above 40 °C: the breaker is rated for up to 95% relative humidity at 55 °C, tapering to 35% at 75 °C. If the panel ambient runs hot, factor that into the load current — the thermal-magnetic trip element responds to ambient temperature, so a breaker in a 60 °C cabinet may trip earlier than its nominal rating suggests.