I.E. Rule No.90: All metal supports of overhead lines and metallic fittings attached there to, shall be permanently and effectively earthed. For this purpose, a continuous earth wire shall be provided and securely fastened to each pole and connected with ordinary at 4 points in every 1.6 km spacing between the points is being as nearly equidistant as possible. Alternatively, each support and metallic fittings attached there to shall be efficiently earthed. Each stay wire shall be similarly earthed unless one insulator has been placed in at a height not less than 3.3 m from the ground.