4Motion Installation Manual, Ver.3.5 - Alvarion

Chapter 2 - Safety and PrecautionsLightning Protection GuidelinesFigure 2-2: Down Conductor and Earth TerminationThe Down Conductor must be straight and vertically installed in order to provide the shortest and mostdirect path to earth. The formation of bends must be avoided.The following table defines the minimum dimensions for down conductors according to IEC 1024-1:Table 2-1: Down Conductor Minimum DimensionsMaterialConductorCu 16Al 25Fe 30It is recommended that the Down-Conductor be at least 50 mm 2 or AWG 0 in all cases.The grounding of the Down Conductor to earth must be of ground resistance no higher than 5 Ohm.This is achieved by using Earth Terminations and, wherever possible, grounding to the steelre-enforcement bars of the concrete base of the tower.4Motion Installation Manual19