The Siemens 5SY4350-7CC is a SENTRON 3-pole miniature circuit breaker with a C tripping characteristic, rated 50 A at AC and 40 °C ambient. It carries a 10 kA breaking capacity per EN 60898, which means it can safely interrupt fault currents up to that level on a 50/60 Hz supply — standard for protecting branch circuits in industrial control panels and distribution boards.
What the ratings mean for fit
The C-curve (tripping between 5 and 10 times rated current) is the go-to for moderate inrush loads like small motors, transformers, and lighting banks — it holds through the start-up spike without nuisance trips. At 50 A rated current, this breaker handles a 50 A continuous load at 35 °C; derate to 47 A at 40 °C, 45.45 A at 45 °C, 43.8 A at 50 °C, and 42.1 A at 55 °C. If your panel ambient runs hot, size the load against the derated figure, not the headline 50 A. The 10 kA breaking capacity per EN 60898 is the standard for residential and light commercial final circuits. For industrial installations where the prospective short-circuit current is higher, check whether your fault level stays under 10 kA — if it exceeds that, you need a higher-rated breaker or a current-limiting upstream device. IP20 with connected conductors means the breaker is protected against finger contact but not against moisture or dust ingress — it belongs inside a sealed enclosure, not on an open panel face in a washdown area. Pollution degree 3 and overvoltage category III confirm it's rated for fixed installations in industrial environments where transient overvoltages are expected.
Mounting and integration
Snaps onto DIN rail via the quick assembly system, occupies 3 modular width units (54 mm). Depth is 76 mm, installation depth 70 mm — check gland plate clearance if the enclosure is shallow. Mounting position any, so vertical or horizontal rail orientation is fine. Combined terminal top and bottom means the line and load conductors land on the same terminal type, simplifying wiring. Sealable design allows the installer to lock the toggle in the off position for lockout/tagout compliance. Halogen-free and silicon-free construction matters if the breaker sits in a clean room or near sensitive electronics where outgassing could cause contact corrosion.