What it is and what it does
The Siemens 5SY7650-6 is a SENTRON miniature circuit breaker (MCB) with a 4-pole, 3P+N design, rated for 50 A at AC. The B-curve tripping characteristic means it trips at 3 to 5 times rated current — standard for protecting cable runs and general-purpose loads in commercial and industrial panels where inrush is low. Breaking capacity is 15 kA per EN 60898 and 20 kA per IEC 60947-2, with a DC rating of 15 kA per IEC 60947-2. That covers most secondary distribution boards and sub-panels in industrial environments. Rated for overvoltage category III and pollution degree 3, so it's suited for fixed installations inside enclosures where conductive dust or condensation is a factor. IP20 with conductors connected — standard for panel-mount breakers.
Thermal derating and ambient range
Full 50 A rating holds at 35 °C ambient. At 45 °C it derates to 47 A, at 50 °C to 45.95 A, at 55 °C to 44.9 A, and at 60 °C to 43.8 A. If your panel runs hot, size the load or the breaker accordingly. Operating ambient range is -40 °C to 75 °C, with humidity limits: max 95% up to 55 °C, tapering to max 35% at 75 °C. That covers outdoor cabinets in cold climates and warm machine enclosures.
Mounting and panel fit
Width is 72 mm (4 modular units), depth 76 mm, installation depth 70 mm. Fastens via the quick-assembly system — snaps onto DIN rail in any mounting position. Combined terminals top and bottom accept supply from either direction. Sealable and touch-protected. Halogen-free and silicon-free construction — relevant for environments sensitive to outgassing, like clean rooms or food processing lines.