1. Test of Coating Thickness The most straightforward way to check copper thickness is by means of a coating thickness gauge (frequently a magnetic or eddy current tester). The device is measuring from the sensor to the steel core and gives a precise measurement of the copper layer in microns. IEC 62561-2 and UL 467 state that the minimum copper coating thickness of earthing rods sho... https://www.pioneerpowers.com/copper-bonded-earth-rod.php