The minimum thickness of copper for durability of copper bonded earthing rods shall be 0.254 mm or 254 microns. The standard is as per international regulations like UL 467 and IEC 62561, which state the copper layer on the steel core shall not be less than 0.010 inch at any point on the rod. This enables excellent corrosion resistance, mechanical strength, and long service life even ... https://www.pioneerpowers.com/copper-bonded-earth-rod.php