The A9N26979 is a Schneider Electric MSU overvoltage release from the Librio Prodis Acti9 Clario range. It trips when the control circuit voltage exceeds 275 V, protecting downstream equipment from sustained overvoltage conditions on a 230 V AC 50 Hz supply.
This part is obsolete per the manufacturer's lifecycle status.
Fixed mounting on 35 mm DIN rail. Clamp terminals accept one flexible cable up to 2.5 mm²; strip 9 mm, torque to 1 N·m. The white housing carries a local action indicator for visual trip confirmation. Ambient operating range -25 to 50 °C, storage -40 to 85 °C, with 95% RH at 55 °C.
Designed to EN/IEC 60947-5-1, the standard for control circuit devices and switching elements. Tropicalisation treatment per that same standard for humid environments. The 275 V threshold tripping voltage is the key selection parameter — confirm it matches your system's overvoltage protection coordination.