The Clip-On Current Transformer (Sensing) is used along with the Fluke 1623 or the Fluke 1625 to perform Selective and Stakeless testing. Selective testing means using one clamp along with earth ground stakes to provide earth ground loop resistance values for one earth ground electrode.
Stakeless testing uses two clamps to perform earth ground loop resistance measurement without stakes. Both tests have the advantage of providing measurements with no disconnection from the grounding system!
Safer and quicker. Already included in the Fluke 1625 Kit. The clamp has a 50.8 mm (2-inch) inner diameter.