The Schneider Electric A9K23663 is a 1P+N miniature circuit breaker from the Acti9 iK60N series, rated 63 A at 30 °C with a B-curve trip characteristic (magnetic trip between 3 and 5 times In). Breaking capacity is 6000 A Icn at 230 V AC, 50/60 Hz, per EN/IEC 60898-1 — enough for most final-distribution fault levels, but check your prospective short-circuit current before committing the BOM line.
Rated 63 A at 30 °C ambient. That is the continuous current the thermal element carries without tripping. Above 30 °C you derate per the standard curve — a panel running at 40 °C knocks about 5 % off that figure. The B curve trips the magnetic element at 3–5× In (189–315 A), which suits resistive and general-purpose loads; it avoids nuisance trips on modest inrush that a C curve would ignore. The 440 V rated insulation voltage (Ui) covers 230/400 V networks with margin.
Width is 36 mm (4 × 9 mm pitches), so it occupies two standard module spaces. Neutral is on the left, which matters when laying out a multi-row panel — keep the busbar orientation consistent. Terminals accept 1 to 35 mm² rigid wire; strip 14 mm and torque to 3.5 N.m. The single terminal per pole (top and bottom) is straightforward for a panel wireman — no piggyback lugs, just one conductor per side. IP20 finger-safe only — this breaker lives inside a closed panel, not on the surface.