Fluke 1620 Series GEO Earth Ground Testers

Fluke Earth Ground Testers

Fluke earth ground testers are the test equipment Irish utilities, electrical engineers, and electrical contractors use to verify the integrity of earthing electrodes, bonding systems, and substation earth grids. Powerpoint Engineering supplies the full Fluke earth ground tester range, from the Fluke 1621 entry-level model through the 1623-2 and 1625-2 GEO earth ground testers up to the 1630-2 FC stakeless ground loop tester, alongside calibration, accessories, and operator training.

Earth resistance is one of the simplest electrical safety properties to specify and one of the harder ones to actually measure. Soil resistivity changes with the seasons, electrodes corrode, and bonding connections loosen. A poor earth connection can undermine the protective device coordination of an entire installation without anyone noticing until something faults.

Earth ground test methods covered

• 3-pole and 4-pole fall-of-potential: the reference test method for measuring the resistance of an isolated earth electrode against a remote current and potential probe.
• 2-pole simplified method: a faster alternative where a low-resistance reference earth is available.
• Stakeless / clamp-on earth testing: measure the loop resistance of a bonded earth without disconnecting it from the system, useful where stakes cannot be driven and the system has multiple parallel paths to earth.
• Selective testing with clamps: isolate the contribution of a single electrode in a multi-electrode system without disconnecting the bonding.
• Soil resistivity using the Wenner four-pin method, a key input for new earthing system design.

Modern Fluke earth ground tester kits cover all four types of earth ground measurement testing methods in a single instrument, so a substation engineer with a 1625-2 GEO can pick the right approach for the site rather than carrying multiple instruments.

Which Fluke earth ground tester is right for the job

The right model depends on the test methods you need and the noise environment you work in:

• Fluke 1621: 3-pole fall-of-potential, suitable for routine electrode resistance testing on simple installations.
• Fluke 1623-2: 3-pole, 4-pole, selective, and stakeless testing for general utility, industrial, and contractor work.
• Fluke 1625-2 GEO: full method set including soil resistivity, automated frequency selection, and adjustable test current for noisy substation environments.
• Fluke 1630-2 FC: stakeless clamp-on earth ground loop tester, ideal where probes cannot be driven (urban substations, paved sites, dense bonded networks).

Specifications: what to confirm before you order

Target users and applications

• Utilities and DNOs verifying substation earthing grids, transformer earths, and pole-mount electrode resistance
• Electrical engineers designing and signing off earthing systems against ETCI / IEC requirements
• Electrical contractors carrying out periodic inspection and testing of installation earthing
• Lightning protection installers verifying the resistance of LPS earth electrodes
• Telecom and renewable site engineers measuring earthing on cellular masts, wind turbines, and solar plant

Typical applications include commissioning earthing systems, periodic verification of installation earth, lightning protection electrode testing, substation earth grid measurement, and stakeless testing on dense urban sites where the fall-of-potential method is not practical.

As authorised Fluke distributor in Ireland, Powerpoint Engineering supplies the full Fluke earth ground tester range with in-house calibration and repair, accessory supply, and operator training in earth ground testing methods.

FAQs

What is the difference between staked and stakeless earth testing?

Staked methods (3-pole and 4-pole fall-of-potential) require driven probes and the test electrode disconnected from the system. Stakeless methods use a clamp-on or dual-clamp arrangement on a bonded earth conductor and measure the loop resistance without disconnection. Stakeless is faster and avoids disconnection risk but only works where parallel earth paths exist.

Which Fluke earth ground tester is best for a substation?

The Fluke 1625-2 GEO earth ground tester is the typical substation choice because of its adjustable test frequency, automated frequency selection, and full method support. For dense urban substations where probes cannot be driven, pair it with a 1630-2 FC for stakeless work.

How often should an earth electrode be tested?

Following ETCI and IEC guidance, earth electrodes should be tested on commissioning and at periodic inspection intervals appropriate to the installation. Critical assets such as substations and lightning protection systems are typically tested annually.

To match the right Fluke earth ground tester to your sites, methods, and reporting needs, request a quote or speak to our team for compatibility advice.