ITU-T - International Telecommunication Union/ITU Telcommunication Sector
适用范围
This Recommendation provides the rationale and formulas for calculating the shielding factors used in series K Recommendations dealing with lightning protection of telecommunication lines and structures. The shielding factors considered are related to: ?C the use of a metallic tower to hold telecommunication feeder cables and antennas; ?C the placement of several feeder cables in a metallic cable ladder in the tower; ?C the placement of telecommunication cables in a metallic cable tray; ?C the use of a guard-wire above a buried telecommunication cable; ?C the connection of a telecommunication cable to earth; ?C the use of a telecommunication cable with a metallic sheath.