Siemens 5SY4508-5 — SENTRON MCB for panel builders and spares buyers
It carries characteristic A — the fast-trip curve that opens within a few cycles on moderate overloads, suited for protecting semiconductor circuits, control transformers, or sensitive loads where a B-curve would let too much energy through before tripping. Rated breaking capacity is 10 kA per IEC 60898-1 and 20 kA per IEC 60947-2 at 230 VAC, with a DC rating of 15 kA at 60 V per IEC 60947-2. Under UL 1077 it carries 5 kA — enough for most North American supplementary-protection applications. Lifecycle status is current production, so this is a straightforward BOM-line fill — no last-time-buy scramble.
Characteristic A trips at 2–3× rated current — faster than the more common B (3–5×) or C (5–10×) curves. That matters when the load is a rectifier input, a UPS bypass, or a control-circuit supply where a short spike from a transformer inrush could nuisance-trip a slower breaker. The 10 kA SCCR at 230 VAC (IEC 60898-1) means it safely interrupts faults up to that level without cascading upstream; the 20 kA rating under IEC 60947-2 gives additional headroom for industrial panel designs that spec to the higher standard. The 1P+N design (two poles, one protected phase plus switched neutral) is common in single-phase final subcircuits where the neutral must be disconnected for isolation. Neutral conductor switching is confirmed, so the breaker opens both poles simultaneously.
Ambient temperature range is -40 to 75 °C, with humidity derating above 55 °C: max 95% RH at 55 °C, 55% at 70 °C, 35% at 75 °C. Vibration resistance per IEC 60068-2-6: ±1 mm at 5–25 Hz, 50 m/s² at 25–150 Hz — enough for machine-mounted panels but not for direct engine mounting without additional damping.
Certified to IEC/EN 60898-1 (domestic-style MCB) and IEC/EN 60947-2 (industrial MCCB standard), plus UL 1077 for North American supplementary protection. CSA C22.2 No.235 also listed. The dual-standard rating means the same part can be specified for panels destined for both IEC and UL markets, simplifying BOM consolidation. The manufacturer provides the standard declaration of conformity, CE marking, and the full IEC/UL test reports. RoHS and REACH compliance documentation is available on request through the supply channel.