The Schneider Electric A9L16689 is a Type 2 surge arrester cartridge from the Acti9 range, designated C20-340. It plugs into an iPRD base module to protect electrical distribution networks in TT or TN earthing systems. The MOV-based design handles a maximum discharge current of 20 kA and a nominal discharge current of 5 kA, with a voltage protection level below 1.1 kV and a response time under 25 ns.
Type 2 classification (per EN 61643-11 / IEC 61643-1) means this cartridge is designed for main distribution-board protection against induced surge currents from lightning strikes — not direct-strike (Type 1) protection. The 20 kA maximum discharge current tells you the worst single surge it can safely clamp; the 5 kA nominal discharge current is the more typical impulse it sees in service. A protection level below 1.1 kV means downstream equipment with a 1.5 kV impulse withstand (typical for industrial controls) stays within its rated margin. The <25 ns response time is fast enough to clip a surge before it propagates into sensitive electronics.
Physical integration
The cartridge measures 18 mm wide, 50 mm high, and 60 mm deep — a single-module width that fits standard DIN-rail enclosures alongside other Acti9 breakers and accessories. The white (RAL 9003) PBT housing carries a red/white flag indicator for local status. The front face is rated IP20, so it is touch-safe in a closed panel but not suitable for washdown environments.