What this 4-pole B-curve 63 A MCB delivers
The Siemens SENTRON 5SJ6463-6 is a 4-pole miniature circuit breaker rated 63 A at 400 V AC, with a B tripping characteristic and a 6 kA breaking capacity certified to both EN 60898 and IEC 60947-2.
The 6 kA rated short-circuit capacity (Icn per EN 60898, Icu per IEC 60947-2) is the standard residential and light-commercial fault level across most of Europe and Asia. At 400 V three-phase, 6 kA prospective fault current covers the majority of distribution boards downstream of a larger upstream breaker or transformer. The energy limiting class of 3 means this MCB restricts let-through energy enough to protect downstream wiring and connected equipment under short-circuit conditions — a coordination detail worth verifying against the upstream protective device's let-through curve if the panel feeds sensitive electronics.
Installation and wiring
The terminal accepts solid or stranded conductors from 0.75 mm² up to 25 mm², which covers everything from 1.5 mm² lighting tails to 16 mm² subfeed cables. The IP20 rating (with conductors connected) is standard for enclosed distribution boards; no special sealing is required inside a panel. Touch protection is built into the terminals, so accidental contact during maintenance is prevented as long as conductors are properly terminated.
For a BOM line that needs this exact 4-pole 63 A B-curve MCB, the 5SJ6463-6 is the correct order code — no parametric substitute is required.