Parameter Description / Value Brand & Range Schneider Electric, Acti 9 series - iPRU surge protective device range. Type / Class Type 2 (Class II). For installation at the main distribution board or sub-distribution level, coordinated with upstream overcurrent protection device (typically a circuit breaker or fuse). Protection Mode 1P+N (L-N, N-PE). Protects between Line and Neutral, and also between Neutral and Earth. Nominal System Voltage (Un) 230V AC (50/60 Hz) - Single phase. Maximum Continuous Operating Voltage (Uc) 320V AC. The maximum voltage the SPD can withstand continuously. Nominal Discharge Current (In - 8/20 µs) 20 kA per pole. This is the test current the device is certified to withstand 15 times. Maximum Discharge Current (Imax - 8/20 µs) 40 kA. This is the maximum single surge current the SPD can handle once. This is the key parameter highlighted in your query (40kA). Voltage Protection Level (Up) at In ≤ 1.5 kV. The residual voltage that appears across the terminals during a surge discharge; a lower value indicates better protection for downstream equipment. Response Time < 25 ns (nanoseconds). Backup Overcurrent Protection (Required) A dedicated Curve C miniature circuit breaker (MCB) is required upstream of the SPD, typically 20A or 32A as per manufacturer's instructions. Status Indicator Visual (Green/Red window) + Remote signaling contacts (1 changeover contact). Connection Screw clamp terminals, suitable for solid or stranded cables. Mounting DIN-rail mounting (EN 60715), 2 modules wide (36mm). Standards Complies with IEC/EN 61643-11. Short-Circuit Withstand Rating Complies with the conditional short-circuit test as per standard.