The Schneider Electric A9F06663 is an Acti9 iC60H miniature circuit breaker rated at 63 A with a B-curve trip characteristic, in a 1P+N (single-pole switched neutral) format. Rated 63 A continuous, so it handles a 63 A resistive or moderate inductive load without nuisance tripping. The B-curve magnetic trip fires at 4 x In (252 A) within ±20%, which means it clears short circuits fast enough for most distribution and general-purpose branch circuits, but it's not for high-inrush loads like motor starting — that's a C or D curve job.
The iC60H carries a 42 kA Icu at 12…60 V AC, 30 kA at 100…133 V AC, and 15 kA at 220…240 V AC per EN/IEC 60947-2. Under the domestic standard (60898-1) it's rated 10,000 A Icn at 230 V AC. That 15 kA at 240 V is the number most panel builders care about for North American 120/240 V split-phase distribution — it's well above typical available fault current in commercial panels, so you're not chasing coordination issues on a 10 kA AIC limit. The 42 kA Icu at low voltage (12…60 V AC) matters for control transformers and low-voltage distribution — it's rare to see that high a rating at 48 V or 60 V, so if you're feeding a 48 V control bus downstream of the main, this breaker doesn't become the weak link.
Mounting and integration — drops into the old footprint
Snaps onto standard DIN rail (35 mm per EN 60715), occupies 4 x 9 mm pitches (36 mm wide). The 1P+N format — neutral switched on the left, phase on the right — matches the standard Acti9 busbar arrangement, so it slots into an existing Acti9 distribution board without re-bussing. Double terminals top and bottom accept 1…35 mm² rigid or 1…25 mm² flexible, with a tightening torque of 3.5 N·m. Stripping length is 14 mm. The toggle handle and trip-indicator window give local status without opening the door. If you're swapping out an older 63 A single-pole MCB with a neutral link, this unit replaces both in one module — no need to gut the whole line.