Schneider Electric M9F23120 Supplementary Protector

The Schneider Electric M9F23120 is a supplementary protector for equipment-level overcurrent protection. Select it for applications requiring supplementary protection under UL 1077 or CSA C22.2 No 235.

Use the 20A rating when coordinating the protector with the circuit load and conductors. Its thermal trip is calibrated at 25°C, so consider the installation temperature when evaluating overload behavior.

The thermal element responds to sustained overloads, while the magnetic element responds to high fault currents. A D curve has a higher instantaneous pickup threshold suited to high-inrush loads, so selection should account for both starting current and fault-clearing requirements.

The rated voltages are 240VAC, 415VAC and 60VDC, with a 50/60Hz frequency rating for AC use. Select by the circuit voltage and supply type, then check the interrupting rating applicable to that voltage.

At 240VAC, the interrupting rating is 14kA and the Icu rating is 10kA. At 415VAC, Icu is 3kA. Compare available fault current with the rating required by the applicable standard; keep the interrupting and Icu ratings distinct during selection.

At its 60VDC rated voltage, the Icu rating is 20kA. Icu means ultimate short-circuit breaking capacity; use this rating when evaluating available fault current for a DC application requiring an Icu rating.

The screw-clamp terminals accept wire from 18 AWG through 8 AWG. Select conductors within that range and tighten the terminals to 22.1 lb-in (2.5 N·m) for the required connection torque.

It mounts on DIN rail and measures 3.2 in high, 0.7 in wide and 2.8 in deep. Use those dimensions when planning the device layout and wiring space.

The operating temperature range is -30 to 70 °C. Check the temperature at the protector's installation location across expected operating conditions and keep it within that range.