Type 1 surge protection devices are intended for installation in low-voltagepower distribution systems to protect against direct lightning currents andhigh-energy surge events.The device is suitable for 230/400V AC systems at 50/60Hz and can be applied inTT, IT, TN-S, TN-C, and TN-C-S earthing arrangements. Performance is verifiedusing a 10/350µs lightning impulse current waveform, which represents theenergy of direct lightning strikes.Key electrical characteristics include impulse current (Iimp), defining thecapability to safely discharge high-energy lightning currents. The device isnormally installed at the service entrance or main low-voltage distributionpanel of buildings equipped with external lightning protection systems.Design and testing are carried out in accordance with IEC 61643-11 requirements.