The Schneider Electric A9L65121 is a Type 2 surge arrester from the Acti9 iPRD series, device short name iPRD65r. It's a single-pole (1P) MOV-based unit rated for 230 V AC (+/- 10 %) at 50/60 Hz, designed to clamp transient overvoltages on the electrical distribution network. The key numbers for fit: a nominal discharge current of 20 kA (common mode L/PE) and a maximum discharge current of 65 kA (common mode L/PE). The voltage protection level [Up] is under 2.3 kV (type 2, L/PE). It clips onto a DIN rail (clip-on mounting mode) and occupies 18 mm width (2 x 9 mm pitches) on the rail, with a depth of 69 mm and height of 85 mm. The housing is white (RAL 9003).
Where it fits and key ratings
This surge arrester is designed for IT earthing systems, which is the ungrounded or high-impedance grounded system common in hospitals, industrial plants, and data centers where continuity of service is critical. The maximum continuous operating voltage [Uc] is 460 V L/PE (common mode). Temporary overvoltage [Ut] withstand is 337 V L/N for 5 seconds, and 1455 V L/PE for 200 ms in safe failure mode. The short-circuit withstand rating is 5 kA at 415 V phase-to-phase. The manufacturer specifies associated disconnectors: an iC60L 25 A curve C (Icu 25 kA), NG125H or NG125L 50 A curve C (Icu 36 kA or 50 kA), or a gG fuse 80 A (Icu 50 kA). This means the arrester must be paired with one of these upstream devices for proper fault coordination. Terminals are tunnel type, accepting 2.5 to 25 mm² rigid or 4 to 16 mm² flexible (with or without ferrule). Wire stripping length is 14 mm, tightening torque 3.5 N.m. Operating temperature range is -25 to 60 °C, storage -40 to 85 °C, with relative humidity 5 to 95 %. Maximum operating altitude is 2000 m.
Signalling and compliance
This unit includes remote signalling via a 1 C/O (changeover) contact rated 0.25 A / 250 V AC. The ground residual current [Ipe] is 0.6 mA. Standards compliance covers EN 61643-11:2012 and IEC 61643-11:2011, which define the testing and performance requirements for low-voltage surge protective devices.