The 5 Best Earth Resistance Testers [Ranked]
Top5Reviewed is reader-supported. When you buy through links on our site, we may earn an affiliate commission.
There is nothing as abundant on this planet as earth soil itself.
It is such a generic feature of our day-to-day existence, whether we use it to plant crops, till or to excavate in order to build upon.
We sometimes forget that the earth actually has an electrical property- a conductivity that has many industrial utilities. Earth resistance refers to soil's resistance to the passage of an electrical current.
Earth resistance testers provide fast and accurate measurements of resistance via several different testing methods, typically including: 3- and 4-pole Fall-of-Potential testing, stakeless testing and 2-pole testing.
Let's take a look at several of the best-selling earth resistance testers on the market today and see how they stack up.
- Includes all hardware necessary to measure earth ground in 3 ranges from 20 to 2000 Ohm
- Boot Time: Self-test in 0.5 second, boot instantly
- Resistance range: 0.01Ω-200Ω;Resistance resolution:0.001Ω; Clamp Size:Φ1.26"(32mm),Clamp table size: 10.24"×3.54"×2.6"(260mm × 90mm × 66mm)
- ACCURATE EARTH GROUND RESISTANCE TESTING: Measures ground rod resistance using the 3-pole fall of potential method.
- Large dual display with backlight
Our Top Pick
The 5 lb Extech 382252 earth ground resistance tester is our top recommendation. It is equipped to measure in three different ranges from 20 to 2,000 ohms. Additionally it can provide measurements include resistance, continuity, as well as AC/DC voltage.
The Extech the earth resistance tester ships with test leads, a carrying case, a rubber holster, 6 AA batteries, as well as 2 auxiliary earth bars. Users say that it is a solid earth ground resistance tester, especially for electricians that are assessing residential electric system earth grounds; communication grounds like satellite, cable, phone and television; as well as lightning earth grounds.
One electrician who use the Extech discovered numerous earth grounds in rocky and dry soils that were between 200 and 350 ohms, which were much higher than the 25 ohms advised by the National Electric Code. While this particular earth ground resistance tester is not usable for large grounding electrode systems or for scientific applications, it Is a handy and portable tool that comes equipped with a solid carrying case and is endorsed for on-the-job use.
It is certainly a quality resistance tester- though many users write that the instructions are pretty poor. They advise reading the online PDF "Getting Down to Earth" by the industrial equipment company Megger so that you have a solid idea of how to accurately test, as well as understanding soil resistivity factors.
Extech Earth Tester Video Review
- An affordable earth resistance tester option
- Includes everything you need right out of the box
- Small and portable at 5 lbs
- Poor instructions
- Not ideal for larger, industrial applications
How does earth resistance testing work?
In general, the earth is a pretty bad electrical conductor when you compare it with something like copper wire, but if this earth path current is extensive enough the resistance will be low and the earth can actually be a pretty strong conductor. It is because of the sheer abundance of the earth's soil that it becomes a crucial aspect of a healthy and operational electrical system.
Earth resistance can be evaluated in two different ways and for two different fields. The first way involves evaluating the effectiveness of ground grids and the connections that are made with electrical systems to safeguard equipment and personnel. The second is for searching out low resistance earth surface areas, or generating resistance values that can provide exact data concerning depth to bedrock, for instance.
Fall potential Ground Resistance Measurement
Earth resistance testing requires a good deal of planning to ensure that it is safe. There is always the chance that a power system fault will generate an unexpectedly high current that will course into the ground system while the resistance testing is taking place. The result could be higher voltages that will present at the voltage and current probes as well as the terminals of the earth testing kit.
There is certainly a risk associated with this and should be evaluated by the individual who will be conducting the tests in accordance with the IEEE Standard 80- which outlines safety guidelines for substation grounding. It is advisable that the earth resistance testing operator always wear strong rubber gloves as well as utilize a rubber safety mat while in control of the testing kit.
Ground resistance measurements, especially when it concerns an earth electrode system is crucial. It should always be evaluated when electrodes are first implanted and then evaluated periodically at set intervals on an ongoing basis. The two methods of evaluating the electrical grounding system are the Fall-of-Potential method and the Induced Frequency test or as it sometimes known the clamp-on method.
The importance of ground resistance monitoring cannot be overstated- it describes a way of continuously evaluating the behavior and performance of important grounding systems.
These are some of our previous top picks- check out our comparison table at the top of the page for our up-to-date selections.
|Earth Resistance Tester||Price||Rating||Weight||Dimensions|
|The Extech 382252 Earth Ground Resistance Tester Kit||$$||4.8||1.5 lbs||7.9 x 3.6 x 2 inches|
|The Hioki 3151 Earth Resistance Tester||$$$||5.0||5 lbs||6.5 x 4.5 x 3.5 inches|
|The B&K Precision Digital Earth Resistance Meter||$||4.0||1 lb||3.93 x 6.4 x 1.96 inches|
|The Gowe G3000-Digital Earth Resistance Tester||$$$||4.0||N/A||N/A|
If you're looking to purchase a quality earth resistance tester, make sure you have probably evaluated your or your businesses' requirements prior to investing in the equipment. A good earth resistance tester will be able to provide accurate measurements using the bi-pole and tri-pole method, displaying relative measurement between input and reference values.