NOTE:   Lightning protection for the boards Analog and digital subscriber lines are protected on the boards, for up to 2 kV longitudinal voltage and 1 kV transverse voltage, against the high-energy surge voltage with a pulse shape of 10/700 µs and 1.2/50 µs that can be induced by lightning. However, this protection is only effective if the system is properly grounded in accordance with the installation instructions. Grounding Once the HiPath 3000 has been grounded, check the low-impedance ground connection of the system using the ground conductor of the power supply circuit, as well as the low-impedance connection (of the additional permanently-connected protective ground conductor) to the building's potential equalization bus.

NOTE:   External lightning protection In the case of line lengths exceeding 500 m and where the lines exit the building, analog and digital subscriber line modules must be protected by external lightning protection. Lightning protection of this kind is known as "additional primary protection". This is either  installed on the MDF (Main Distribution Frame) or at the entry point of the line into the building. A gas-filled  surge arrester with 230 V nominal voltage is switched to ground from each wire that is to be protected. Without this additional primary protection, lightning that exceeds the voltage values given above could irreparably damage the boards. This can cause the entire system to fail or result in components overheating (risk of fire).