63 A D-curve MCB for high-inrush loads
The Siemens 5SY6263-8 is a SENTRON miniature circuit breaker rated 63 A with a D tripping characteristic, meaning it tolerates the high inrush currents typical of motor starters, transformers, and welding equipment without nuisance tripping — the magnetic trip fires at 10–20× rated current rather than the 5–10× of a C-curve. Rated 400 V AC across 2 poles, it breaks 6 kA per EN 60898 for general distribution and 10 kA per IEC 60947-2 for industrial panel duty — the higher figure is the one that governs fault clearance in a motor control centre with upstream transformer impedance. Wire range 0.75–35 mm² solid or stranded, combined box terminals top and bottom, so it accepts the full cross-section of a 63 A feeder without pigtailing or parallel runs.
IP20 with conductors connected; touch protection built in. Sealable, halogen-free, silicon-free — relevant for food, pharma, or clean-room panels where outgassing or contamination is a concern. Humidity derating applies above 55 °C: max 95% RH at 55 °C, 55% at 70 °C, 35% at 75 °C.
Rated per EN 60898 (6 kA), IEC 60947-2 (10 kA), and UL 1077 / CSA C22.2 No. 235 (5 kA at AC). Overvoltage category III. The UL/CSA listing at 5 kA covers North American supplementary protection applications. Designed for mechanical engineering and industry per the manufacturer's suitability classification. Functional designation per DIN EN 61346-2 and DIN EN 81346-2: F (protective device).