The Fluke 1625 GEO earth ground tester is a distinctive earth ground testers that can perform all four types of earth ground measurement. Specifically, the Fluke 1625 tester is able to measure earth ground loop resistances using only clamps – called Stakeless testing. This method doesn't require the use of earth ground stakes or the disconnection of ground rods.
Testing Methods
- 3- and 4-Pole Fall of Potential – standard earth ground testing using two ground stakes
 - 4-Pole Soil Resistivity testing – determine soil resistivity using four ground stakes
 - Selective testing – without disconnecting ground rods, a technician can measure ground resistance using a combination of stakes and a clamp.
 - Stakeless testing – innovative solution using only clamps, instead of ground stakes, to measure earth ground loop resistance.
 
The Fluke 1625 offers these advanced features:
- Automatic Frequency Control (AFC) – identifies existing interference and chooses a measurement frequency to minimize its effect, providing a more accurate earth ground value.
 - R* measurement – calculates earth ground impedance at 55 Hz to more accurately reflect the earth ground resistance that a fault-to-earth ground would see.
 - Adjustable limits – for quick test result verification.
 

 