What the ratings mean for fit
The 5SY6220-8CC is a Siemens SENTRON miniature circuit breaker with a D tripping characteristic, meaning it is designed to handle high inrush currents — typical for motor, transformer, or welding loads where the starting surge can be 10–14 times the rated current. The 20 A rating at 35 °C is the base; at 40 °C it derates to 18.8 A, at 50 °C to 17.52 A, and at 55 °C to 16.84 A (–). If your panel ambient runs above 35 °C, size the breaker for the derated value, not the nameplate 20 A. The 6 kA breaking capacity per EN 60898 tells you it safely interrupts short-circuit faults up to 6 kA at the rated voltage. For a 2-pole breaker on a 440 V AC line, that covers most industrial distribution sub-panels — but verify the available fault current at the installation point. Overvoltage category III and pollution degree 3 confirm it is rated for fixed-installation use in industrial environments, not just residential. The breaker snaps onto a DIN rail via the quick assembly system and can be mounted in any position. It occupies 2 modular width units — 36 mm wide — so it fits standard 18 mm-per-module enclosures. The 76 mm depth and 70 mm installation depth mean it clears most shallow distribution boards, but check the enclosure door clearance if using a transparent cover.
Integration and compliance
The breaker is halogen-free and silicon-free — relevant for clean-room or sensitive electronics environments where outgassing can cause contact corrosion or optical haze. It is sealable, meaning the toggle can be locked in the off position for lockout/tagout procedures. The combined terminal design at both top and bottom accepts busbar or cable connections without needing separate feed-through lugs. IP20 with connected conductors means it is protected against finger contact but not against water ingress — standard for enclosed panel mounting. The operating temperature range spans -40 °C to 75 °C, so it can sit in an unheated warehouse or a hot machine cabinet without derating beyond the current table.