Overview
The EZ9F53450 is a 4-pole C-curve miniature circuit breaker from the Schneider Easy9 range, rated 50 A and built for 400 V AC distribution boards. Its thermal-magnetic trip unit holds a 3 kA Icu breaking capacity per SANS 60947-2, with a limitation class 3 rating for energy let-through on high-fault installations.
Selection and sizing
At 50 A, this breaker suits main or heavy sub-feed circuits where the 3 kA Icu matches the available fault current at the board; the C-curve magnetic trip at 8.5 x In ±20 % handles motor and lighting inrush without nuisance tripping. The tunnel terminals accept up to 35 mm² rigid or flexible conductors, torqued to 3.5 N.m, which is the same torque spec across the 50 A frame and heavier than the 2 N.m used on lower-current siblings.