The Siemens 5SY5250-6 is a 2-pole miniature circuit breaker from the SENTRON family, rated for universal-current operation (AC/DC). It carries a B tripping characteristic — the standard choice for general lighting and socket-outlet circuits where inrush is moderate — and is certified to both IEC / EN 60898-2 and UL1077, so it fits European and North American panel specs alike. Breaking capacity is 10 kA per EN 60898-2 (AC) and 15 kA per IEC 60947-2 (DC), giving enough fault-current headroom for most commercial and light-industrial distribution boards. The 2-pole design switches both phase and neutral? No — neutral is not switched, so this is a two-pole breaker protecting two line conductors, not a 1P+N. That matters when you're ordering for a split-phase or dual-line feed.
Panel fit and mounting
Width is 36 mm (2 modular units), depth 76 mm, height 90 mm. Installation depth (behind the panel) is 70 mm. Mounts in any position via the quick-assembly system — snaps onto standard DIN rail. IP20 with conductors connected; pollution degree 3 means it tolerates conductive dust typical of industrial enclosures. Overvoltage category III suits fixed-installation distribution boards. Combined terminals top and bottom accept both busbar and wire — no adapter needed for daisy-chaining. Sealable for lockout/tagout compliance. Halogen-free and silicon-free, which matters in clean-room or sensitive electronics environments where outgassing can cause contact corrosion.
Electrical ratings and operating limits
Rated voltage: 400 V AC (single- or multi-phase) and 440 V DC. Maximum DC operating voltage goes to 500 V. Frequency 50/60 Hz. The B curve trips between 3 and 5 times rated current — typical for resistive and general-purpose loads. Energy limitation class 3 means it limits let-through energy well, helping downstream selectivity. Ambient temperature range: -40 °C to +75 °C. Humidity influence: max 95% at 55 °C, derating to 35% at 75 °C. Vibration resistance per IEC 60068-2-6: ±1 mm at 5–25 Hz, 50 m/s² at 25–150 Hz. This holds up in machine-mounted enclosures near rotating equipment.
Lifecycle and sourcing
Current-production part. No end-of-life notice or last-time-buy window on record. Sourced through independent distribution; availability and current pricing confirmed at quote time against an RFQ.