Overview
The EZ9F53310 is a Schneider Easy9 miniature circuit breaker rated 10 A with a C-curve magnetic trip at 8.5 x In, switching a 3-pole AC load on a 400 V supply at 60 Hz. Its thermal-magnetic trip unit and 3 kA Icu breaking capacity meet SANS 60947-2 with Limitation Class 3, making it a fit for distribution boards where short-circuit energy let-through matters.
Selection and sizing
The 3 kA Icu is the maximum short-circuit current the breaker can interrupt at 400 V AC; for panels with higher prospective fault current, a current-limiting upstream device or a higher-rated MCB is needed. The C-curve (8.5 x In magnetic trip) suits mixed resistive and moderate inductive loads such as small motor circuits and lighting banks, rather than pure transformer or capacitor banks where a D-curve would be preferred.
How it compares
Compared to the EZ9F53316 (16 A), the EZ9F53310 carries a 10 A rating — 6 A lower — so the EZ9F53316 is the right choice when the branch load exceeds 10 A continuous, while the EZ9F53310 provides finer overcurrent protection for smaller circuits.