The Fluke 1625-2 GEO Earth Ground Tester with 3-/4-Pole Fallof-Potential, 4-Pole Resistivity, Selective/Stakeless Testing and AFC is able to measure earth ground loop resistances using only clamps. With this test method, two clamps are placed around the earth ground rod and each are connected to the tester. No earth ground stakes are used at all. A known, fixed voltage is induced by one clamp and the current is measured using the second clamp. Then the tester automatically determines the resistance of the earth ground rod.

This test method only works if a bonded earth ground system exists for the building or structure under test, but most are. If there is only one path to ground, like at many residential applications, the Stakeless method will not provide an acceptable value and the Fall-of-Potential test method must be used.

With Stakeless testing, the earth ground rod does not need to be disconnected, leaving the bonded earth ground system intact during test. Gone are the days of spending time placing and connecting stakes for each earth ground rod on your system, which is a major time saver. You can also perform earth ground tests in places you have not considered before, like inside buildings, power pylons, or anywhere you do not have access to soil.

The 1625-2 tester is also easy to use. For each test, it informs you of which stakes or clamps need to be connected; the large rotary switch can be used even with a gloved hand.