The Schneider Electric EZ9F34350 is a 3-pole miniature circuit breaker from the Easy9 range, rated 50 A with a C-curve trip characteristic. It protects branch circuits in distribution panels against overloads and short circuits, with a breaking capacity of 4.5 kA at both 230 V and 400 V AC per IEC 60898-1. The C-curve means magnetic tripping occurs between 5 and 10 times the rated current (250–500 A), which suits mixed resistive and moderate inductive loads like lighting, small motors, and general-purpose outlets in commercial or residential distribution boards.
Clip-on mounting to DIN rail (35 mm per EN 60715) — the 54 mm width occupies 6 module pitches at 9 mm each, so it fits standard distribution board spacing. Depth is 66.5 mm, height 81 mm. Terminal capacity: 1–35 mm² rigid or 1–25 mm² flexible wire per tunnel terminal, tightened to 3.5 N·m.
The 4.5 kA Icn at 400 V AC is the rated short-circuit breaking capacity — the maximum fault current this MCB can safely interrupt. The service breaking capacity (Ics) is 4.5 kA at 100% of Icn, meaning after one fault at rated capacity the breaker can still be reused. For installations where the prospective short-circuit current exceeds 4.5 kA, a higher-rated device is needed upstream. Rated insulation voltage (Ui) is 500 V AC, and operational voltage (Ue) is 400 V AC — the breaker is suitable for 3-phase 400 V line-to-line distribution networks. Pollution degree 2 and tropicalisation class 2 cover normal indoor environments with some humidity and temperature cycling.