Schneider Electric M9F23108 Supplementary Protector

This supplementary protector provides overcurrent protection within equipment. Its UL 1077 classification guides selection for supplementary protection, with branch-circuit protection arranged separately.

Use the 8A current rating when selecting protection for the circuit load. The thermal element responds to sustained overloads, while the magnetic element responds rapidly to high-current faults.

A D curve is useful where brief startup inrush could cause unwanted tripping with a more sensitive magnetic response. Select it by considering both load inrush and the fault current needed to operate the magnetic trip.

Compare available fault current at the installation point with the interrupting rating at the circuit voltage: 10kA at 277VAC, 14kA at 240VAC, 14kA at 120VAC, or 10kA at 65VDC. Available fault current must not exceed the applicable interrupting rating.

The rated voltages are 240VAC, 415VAC, and 60VDC, with 50/60Hz operation for AC applications. Check both the voltage rating and the interrupting rating applicable to your circuit; they address different selection requirements.

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

Plan for DIN rail mounting and a body measuring 3.2 in high, 0.7 in wide, and 2.8 in deep. Use these dimensions for layout, while allowing working space for wiring and toggle operation.

The operating temperature range is -30 to 70 °C, and the calibration temperature is 25°C. Keep the installation environment within the operating range and account for ambient temperature when evaluating thermal trip behavior.

The trip indicator helps you recognize a protective trip, and the toggle provides manual operation. Investigate the cause of the trip before re-energizing the circuit.