measuring ground resistance

[chris1971]

What would be the correct way to measure ground resistance? Specifically measuring to make sure we fall within the 25 ohm requirement.

 

[brian john]

The most accurate method available is the 3 point fall of potential method. This requires some distance to perform (depending on the size of the ground grid.

http://www.aemc.com/techinfo/techworkbooks/ground_resistance_testers/950-WKBK-GROUND-WEB.pdf

http://www.aemc.com/techinfo/appnotes/Ground_Resistance_Testers/APP-Ground-ComparisonofTesters.pdf

 

[chris1971]

Thanks for the websites.

 

[zog]

What would be the correct way to measure ground resistance? Specifically measuring to make sure we fall within the 25 ohm requirement.

Unless you have the equipment and training to the testing properly, you are better off just driving a 2nd rod. You can expect to spend a few grand on the tet equipment and at least an hour or 2 doing the tests and writing the report.