Fluke - The industry benchmark
for earth ground testers


Ensure that installations are protected against lightning strikes and utility over-voltages. And comply with relevant electrical codes, and local and engineering standards. Fluke earth ground testers save time by taking quick and accurate impedance measurements for commerce, industry and utilities. These compact and rugged instruments are easy to use in cramped spaces – and we have two new models (1623-2 and 1625-2).

Principles of
Earth Grounding

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Checking ground electrode impedance for commercial, industrial and residential buildings.

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Down to earth: The Fluke 1621 is our basic and easy-to-use earth ground tester. It has intuitive operation and large, clear LCD display. It is the first line of defence for many electrical contractors, utility test engineers, and earth ground specialists.

  • 3-pole fall-of-potential
  • 2-pole ground resistance tests


Our new Fluke 1623-2 GEO earth ground testers perform all four types of earth ground measurement, including earth ground loop resistance using only clamps. That makes for faster, safer operation because the ground rods don’t need to be disconnected. They offer data storage and download via USB too. And we have a tester kit with everything you need to get started.

  • 3- and 4-pole fall-of-potential
  • selective testing (with one clamp)
  • stakeless testing (with two clamps)
  • optional tester kit with ground stakes, carrying case, etc.


Virtual demo

The new Fluke 1625-2 GEO has the same capabilities as the 1623-2 including selective and stakeless testing, but with wider measurement ranges and AFC. Like the 1623-2, it makes for faster, safer operation because the ground rods don’t need to be disconnected. And once again, this model is available with a tester kit that has everything you need to get started.

  • 2- and 4-pole resistance measurements
  • Automatic Frequency Control (AFC) to minimize interference for better accuracy
  • R* measurements at 55 Hz to replicate a real fault to earth
  • Adjustable limits to ensure quick test result verification
  • Optional tester kit with ground stakes, carrying case, etc.


Virtual demo

The Fluke 1630 uses a clamp meter and stakeless testing to avoid breaking the circuit. That simplifies ground loop and continuity testing without breaking the circuit. The clamp simply encircles the earth ground rod or connecting cable.



The testing methods in brief

2-pole testing uses nearby metal structures like metal water pipes as a temporary stake.

3-pole testing uses two stakes to inject the current and give the 0 V reference.

4-pole testing is similar to 3-pole testing, but has an additional stake for improved (x10) resolution. It is ideal for power transmission and distribution companies, who need to measure very low values of earth resistance.

Selective testing measures earth ground loop resistance without disconnecting ground rods, using a combination of ground stakes and a clamp.

Stakeless testing measures ground loop resistance by inducing a voltage in one half of the clamp and measuring the current in the other half. It enables electricians to test equipment inside buildings or on power pylons, where other techniques are not possible. It is not suitable where there is only a single path to ground, though, as in domestic systems.

Which earth ground tester is right for you?

 Selective and stakeless testing
 3-pole fall of potential
 2-Pole ground resistance tests
 3- and 4-pole Fall of Potential, earth resistance loop testing
 Selective testing (1 clamp)
 Stakeless testing (2 clamps)
 2-and 4-pole resistance measurement DC
 Automatic frequency control (AFC) 
 R* measurements at 55 Hz
 Adjustable limits for fast test verification
 4-Pole soil resistivity testing
 Clamp meter and stakeless testing
 Ground leakage current










Reduce your workplace environment risks with our safety programs.

FLUKE safety programs


Work accurately and get the most out of your test tools with our certified training.

FLUKE training


Try out our products with virtual demos before you buy.

FLUKE virtual demos

Where to buy

You can always turn to our Distributors and Service Centers for local assistance. They’ll help you with traceability, calibration, repair, and self maintenance.

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