The Schneider Electric A9L40271 is a Type 2 surge arrester from the Acti9 iPRD PV-DC series, designed specifically for photovoltaic DC circuits. It protects downstream equipment against induced lightning surges and switching transients on the DC side of a solar array. Rated for 800 VDC ±10 % (Ue), it handles the open-circuit voltage of a PV string under standard test conditions up to 666 V (Uoc STC). The MOV (metal-oxide varistor) technology gives a response time ≤25 ns, clamping surges to a protection level (Up) below 3 kV in differential and common modes. With a nominal discharge current (In) of 15 kA and a maximum discharge current (Imax) of 40 kA, it is sized for the surge exposure typical of rooftop and ground-mount PV installations. The 2-pole construction covers L+/L- and L+/PE paths.
The 6-module width (54 mm) and 69 mm depth fit standard distribution boards. Tunnel-type terminals accept rigid cable up to 25 mm² or flexible up to 16 mm². The integrated disconnector allows safe cartridge replacement without removing wiring. A white/red flag on the front gives local status; the volt-free changeover contact (1 C/O) provides remote signalling to a BMS or PLC.
Rated for indoor installation (IP40 front, IP20 terminals) with an IK03 impact rating. Complies with EN 50539-11:2013 and UTE C 61740-51 for PV surge protective devices.