What it is and what it does
The Siemens SENTRON 5SY7250-7 is a 2-pole miniature circuit breaker with a C-curve trip characteristic, rated 50 A at AC. It carries a breaking capacity of 15 kA per EN 60898-1 and 20 kA per IEC 60947-2, with a DC rating of 15 kA per IEC 60947-2. That dual-standard rating means it's certified for both residential-style distribution panels (EN 60898) and industrial panelboard applications (IEC 60947-2) — a single SKU that covers both spec books. The C-curve trips between 5 and 10 times rated current, so it's sized for motor-starting inrush and moderate inductive loads — common on conveyor drives, pumps, and small compressors in mechanical engineering and industry.
Panel fit and mounting
Width is 36 mm (2 modular units), depth 76 mm, height 90 mm. Snaps onto DIN rail via the quick-assembly system in any mounting position. Installation depth is 70 mm — that's the clearance behind the panel door you need to budget. IP20 with connected conductors means it's protected against solid objects larger than 12 mm but not against moisture; keep it inside a sealed enclosure. Combined terminals top and bottom accept both busbar and cable, which simplifies daisy-chaining in a multi-pole distribution block. Sealable — you can lock the toggle to prevent unauthorized reset.
Thermal derating and environment
Rated 50 A at 35 °C ambient; at 40 °C it's 47.6 A, at 50 °C it's 45.1 A, at 60 °C it's 42.4 A. If your panel runs hot — say near a drive or transformer — size the upstream protection for the derated value, not the 50 A label. Ambient range is -40 to 75 °C, pollution degree 3, overvoltage category III. Halogen-free and silicon-free — relevant if the panel is in a clean-room or semiconductor fab where outgassing matters.