Clamp-on current transformer is used with an earth ground tester to take ground loop resistance measurements around transmission line pylons Compatible with Fluke 1623 and Fluke 1625 ground earth tester kits Allows measurement of individual resistances for each tower leg without disconnecting ground leads, overhead static wires, or ground wires Transformer has 1,000 windings, with transformation ratios of 1,000, 500, 300, 200, and 0 available to set before use for expected minimum measuring and maximum parasitic currents Includes two fasteners for holding transformer halves together, cable bobbin with two 12m/40ft. test leads for connecting transformer to tester, contact clamp, and carrying case