Siemens SENTRON 5SY4263-8FA — 63 A D-Curve MCB for Industrial Panels
The 63 A continuous rating at 400 V AC defines the maximum resistive load it carries without tripping. The D-curve's magnetic trip threshold (10–20 times rated current) ensures it rides through motor starting surges — a 63 A D-curve holds through a 630–1260 A inrush pulse for a few cycles, then clears a hard short. Overvoltage category III confirms it's rated for fixed-installation distribution boards, not just downstream equipment.
At 36 mm wide (2 width units,), it occupies two adjacent slots in a distribution board. The screw terminals accept solid or stranded copper from 0.75 mm² up to 35 mm², with a tightening torque of 3.5 N·m. Combined terminals top and bottom allow busbar or ring-tongue connection without adapters. Sealable for lockout/tagout. Touch protection is integral — no additional finger-safe shrouds needed.