16mm High Strength Earth Rod 5/8″ UNC . 1200mm nominal length Copperbond Earth Rods, deep driven, usually provide the most cost effective earth system. They are made from a low carbon, high tensile strength (minimum 600n/mm2) steel core with a coating of 99.9% pure electrolytic copper, that has been molecularly bonded to the steel core. Extendable type rods have a rolled thread (UNC2A) at each end. Rolled threads have a higher strength than cut threads. Additionally, they preserve the copper coating. Compliance: BS 7430, BS:EN 62561-2: 2012