The Schneider Electric A9L16618 is an Acti9 iQuick PF Type 2 surge arrester in a 3-pole + N configuration, rated for 230/400 V AC distribution networks. It uses MOV + GDT technology to clamp transient overvoltages, with a nominal discharge current of 20 kA in common mode (N/PE) and 5 kA differential (L/N). The maximum discharge current hits 20 kA common mode and 10 kA differential — meaning it can handle repeated lightning-induced surges on a TT or TN-S earthing system without failing open. The continuous operating voltage is 275 V for both L/N and L/PE modes, with a protection level below 1.5 kV. Temporary overvoltage withstand is 337 V L/N for 5 seconds, and 1200 V N/PE for 200 ms in safe failure mode — so it survives a lost-neutral event without catching fire, then fails safe.
Clip-on DIN rail mount, 9.8 module pitches wide (88.4 mm). Depth is 74.1 mm, height 106.7 mm. That 74.1 mm depth matters when you're packing it into a shallow wall-mount enclosure — measure your gland plate clearance before committing the BOM line.
Operating temperature range is -25 to 70 °C, storage -40 to 80 °C, with 5–95% relative humidity. The integrated disconnector (circuit breaker, Icu 6 kA) means you don't need an external MCB for short-circuit backup up to 6 kA.