The Siemens 5SJ4263-7HG41 is a SENTRON 5SJ4 miniature circuit breaker (MCB) rated 63 A at 40 °C with a C-curve trip characteristic, 2 poles, and a 10 kA breaking capacity per EN 60898. It snaps onto standard DIN rail (35 mm) and occupies 2 modular width units (36 mm). The C-curve means it trips between 5 and 10 times rated current — standard for motor-starter and general-purpose branch-circuit protection where moderate inrush is expected. The 10 kA SCCR at 400 V AC means it safely interrupts fault currents up to that level without cascading upstream, sized for most commercial and light industrial distribution boards.
Thermal derating and operating range
Rated 63 A continuously at 30 °C and 40 °C. Derates to 61.7 A at 45 °C, 60.4 A at 50 °C, 59.1 A at 55 °C, and 58 A at 60 °C. Ambient operating range is -40 °C to 75 °C. For a panel running at 50 °C ambient, expect a usable continuous current of 60.4 A — roughly 4% headroom loss from the nameplate. The DC rating maxes at 60 V, so it can serve DC branch circuits up to that voltage, but the 10 kA breaking capacity is specified per EN 60898 (AC).