Gmax make Copper Bonded Steel Electrode Rod The earth electrode shall be made of high tensile low carbon steel circular rods, molecularly bonded with copper on outer surface to meet the requirements of Underwriters Laboratories (UL) 467-2007 or latest. Such copper bonded steel cored rod is preferred due to its overall combination of strength, corrosion resistance, low resistance path to earth and cost effectiveness. The earth electrode shall be UL listed and of minimum 17.0mm diameter and minimum 3.0mtrs. long. The minimum copper bonding thickness shall be of 250 microns. Marking: UL marking, Manufacturer’s name or trade name, length, diameter, catalogue number must be punched on every earth electrode.