NFPA 780: Standard for the Installation of Lightning by Nfpa

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3 For nonmetallic masts using a pole guy wire as a down conductor, the guy wire shall be a continuous metal cable without any ceramic or insulating sections. 4. 4 Each metallic guy cable shall be bonded at its lower end to the grounding electrode(s). 2 Grounding of Masts. 9 m (3 ft) from the structure foundation or footing. 13. 4 Radials. 5. 2. 5 Ground Plate Electrodes. 6. 3 Overhead Wire (Catenary) Systems. 4, using a striking distance of 30 m (100 ft) radius. 6 Earth Enhancement. Chemical grounds installed for the specific purpose of providing electrical contact with the earth or a conductor immersed in nearby salt water shall be permitted.

1. 1 Any non–fully submerged conductive seal assembly components, including springs, scissor assemblies, and seal membranes, shall be electrically insulated from the tank roof. 4 For grounded metallic masts, the air terminal and the down conductor shall not be required. 2 The insulation level shall be rated 1 kV or greater. 4 Protection of Specific Classes of Structures. 1 Aboveground Tanks at Atmospheric Pressure Containing Flammable Vapors or Liquids That Give Off Flammable Vapors. 1* Fixed-Roof Tanks (Metallic) and Tanks with Internal Floating Roofs.

3 Protection of Electrical and Mechanical Control Systems. 18. 4 Grounding. 14, and interconnect to the site grounding system, if present. 8. 2* The grounding system shall include a ground ring electrode external to the foundation, in contact with the soil, and bonded to the foundation reinforcing steel using fittings listed for the purpose. 3 Reinforcing steel shall be made electrically continuous throughout construction by interconnection of vertical and horizontal bars. 4 Down conductors coursed on or in reinforced concrete construction shall be connected to the reinforcing steel at their upper and lower extremities.

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