The Siemens 5SY4140-7CC is a SENTRON miniature circuit breaker (MCB) — a 1-pole, 40 A device with C-curve tripping characteristic, rated to interrupt 10 kA under IEC 60898. It occupies a single 18 mm modular width on a DIN rail, quick-assembly fastening, and mounts in any position. The IP20 rating applies with connected conductors — expected for panel-mounted breakers; the enclosure provides the rest of the ingress protection.
Ratings that govern fit
The headline 40 A rating holds at 35 °C ambient. Above that, the breaker derates: 36.76 A at 40 °C, 35 A at 45 °C, 33.16 A at 50 °C, and 31.24 A at 55 °C. Breaking capacity: 10 kA per IEC 60898, 5 kA per UL 1077 and CSA C22.2 No.235. Vibration resistance per IEC 60068-2-6: ±1 mm at 5 to 25 Hz, 50 m/s² at 25 to 150 Hz — enough for normal machine-mounted panels; not a concern unless the panel is on a high-vibration platform like a large press or engine test stand.
The combined terminal at top and bottom accepts standard copper conductors. Sealable design allows lockout/tagout. Halogen-free and silicon-free construction — no silicone outgassing to foul contacts or optics in adjacent sensors.