Schneider Electric M9F42303 3A 3-pole C-curve miniature circuit breaker

Schneider M9F42303 3-pole C-curve breaker

The Schneider Electric M9F42303 is a three-pole miniature circuit breaker from the Multi9 series rated at 3 amps with a C-curve trip characteristic. It provides branch circuit protection for three-phase AC systems in commercial and industrial installations. The unit mounts on standard DIN rail and uses screw-clamp terminals for secure conductor connections. It is suited for electricians and panel builders assembling load centres or distribution boards.

14 kA interrupting rating at 120/240 V AC

The breaker carries a maximum AIR rating of 14 kA at 120/240 V AC, which determines whether it can safely clear prospective fault currents in the target panel. This rating must meet or exceed the available short-circuit current at the point of installation. The device is also UL 489 listed for branch circuit protection and accepts conductors from 18 AWG up to 8 AWG. It is not rated for DC applications.

Fits 63 A C60BP frame on DIN rail

The M9F42303 fits within the 63 A C60BP frame size and occupies a standard DIN rail mounting footprint measuring 4.06 inches long, 2.13 inches wide and 2.83 inches deep. Its three-pole format frees up space compared to using three single-pole breakers while delivering coordinated thermal-magnetic trip performance. The screw-clamp terminals speed up wiring during panel assembly or retrofit work. Buyers needing DC-rated protection or a different interrupting capacity should select an alternative device.