What the ratings mean for fit
The Siemens 5SY5225-7CC is a 2-pole miniature circuit breaker from the SENTRON series, rated 25 A at 35 °C with a C tripping characteristic. The C curve means it handles moderate inrush — typical for motor starters, small transformers, and lighting banks in industrial panels — without nuisance trips on startup. The 10 kA DC breaking capacity at 440 V (per IEC 60947-2) tells you it can safely interrupt a fault up to that level on a DC bus, which is the figure that governs coordination with upstream protective devices. At 40 °C the continuous rating derates to 23.3 A, at 50 °C to 21.45 A — so if your panel ambient runs warm, size the load against the derated number, not the 35 °C headline.
Panel integration
Snaps onto DIN rail via the quick-assembly system, occupies 2 modular width units (36 mm), and mounts in any position. Depth is 76 mm with 70 mm installation depth behind the panel. IP20 with connected conductors — fine for enclosed industrial panels, not for wet washdown zones. The combined terminal top and bottom accept solid or ferruled stranded conductors; polarity must be observed on the DC supply side.
Environmental and compliance
Rated for ambient temperatures from -40 °C to 75 °C, with humidity limits per the spec (max 95% at 55 °C, derating to 35% at 75 °C). Halogen-free and silicon-free construction. Vibration resistance per IEC 60068-2-6: ±1 mm at 5 to 25 Hz, 50 m/s² at 25 to 150 Hz. Overvoltage category III, pollution degree 3 — suitable for industrial fixed-installation environments.