The Siemens 5SY7250-8 is a SENTRON 2-pole miniature circuit breaker with D-curve tripping, rated 15 kA breaking capacity per IEC/EN 60898-1 and IEC 60947-2 at 400 VAC. The D characteristic means it tolerates the high inrush currents of motor or transformer loads without nuisance tripping — the magnetic trip threshold is 10–20× rated current, sized for inductive starts. At 36 mm wide (2 modular units), it snaps onto a DIN rail and fits standard 18 mm-per-pole panel layouts. The quick-assembly fastening and any mounting position simplify panel integration.
DIN-rail mount, 36 mm wide (2 MW), depth 76 mm with 70 mm installation depth. Combined top and bottom terminals accept feed-through wiring. Sealable with a lead seal for metering or tamper-proof applications. IP20 with conductors connected — standard for enclosed panelboards.
Rated for pollution degree 3 and overvoltage category III, so it's suited for industrial environments where conductive deposits or transient overvoltages are expected. Vibration resistance per IEC 60068-2-6 covers ±1 mm at 5–25 Hz and 50 m/s² at 25–150 Hz — typical for machine-mounted panels. Approvals include IEC/EN 60898-1, IEC/EN 60947-2, and UL 1077 / CSA C22.2 No. 235. The UL 1077 supplementary-protector rating is 5 kA — check that your fault-current study stays under that threshold if the installation requires UL listing.