The Siemens 5SY4650-7CV is a 4-pole miniature circuit breaker (MCB) with a C-curve tripping characteristic, rated 50 A at 35 °C and 440 V AC. It's built to IEC / EN 60947-2, which covers the breaking capacity and coordination requirements for industrial and commercial distribution boards — not just residential lighting panels. That's the number that decides whether this breaker holds its line in a high-fault panel. Rated current is 50 A at 35 °C, but it derates as the cabinet warms: 47.25 A at 40 °C, 45.8 A at 45 °C, 44.3 A at 50 °C, 42.75 A at 55 °C (–). If your panel runs at 50 °C ambient, the breaker's effective continuous current is 44.3 A — not the 50 A on the label. That derating curve is the spec that governs real-world fill factor in a crowded enclosure. Neutral conductor is switched, so this 4-pole unit opens all four poles including the neutral. That's expected for TN-S or TT systems where you need full isolation on the outgoing circuit. Four modular width units wide — 72 mm face width.
Lifecycle stage is current production. No phase-out notice or last-time-buy date on record.
Environmental and installation notes
Humidity influence is specified: max 95% up to 55 °C, derating to 55% at 70 °C, and 35% at 75 °C. Vibration resistance per IEC 60068-2-6: ±1 mm at 5–25 Hz and 50 m/s² at 25–150 Hz — enough for machine-mounted panels on pumps or compressors. Halogen-free and silicon-free construction. Degree of pollution 3 — suitable for conductive environments like industrial floors. IP20 with conductors connected — protected against finger contact, not against water ingress. Sealable for tamper-evident applications.