What this MCB does in the panel
The Schneider Electric EZ9F34463 is a 4-pole miniature circuit breaker from the Easy9 range, rated 63 A with a C-curve trip characteristic (magnetic tripping between 5 and 10 times In). The 4.5 kA breaking capacity at both 230 V and 400 V AC (conforming to IEC 60898-1) means it safely interrupts fault currents up to that level without cascading upstream — a solid fit for residential or light commercial final-distribution boards where the prospective short-circuit current stays under that threshold.
Clip-on mounting to a standard DIN rail, 72 mm wide (8 x 9 mm pitches).
The 63 A rating and 4-pole configuration suit it as a main incomer or large subfeed breaker in a single-phase or three-phase distribution board. Thermal-magnetic trip technology means no electronic adjustment; it's a fixed-characteristic device, so selectivity studies rely on the time-current curve published in the datasheet.