How to check ground rod resistance

Updated February 21, 2017

A ground rod provides a safe path for electricity to follow in the event of a short circuit. To this end, electrical code requires that all electrical installations have a grounding rod installed. A grounding rod is a metal rod that is driven into the earth and attached to the electrical service panel with a conductive wire. Exposure to the elements, soil acidity and extreme temperatures can corrode this rod over time increasing its resistance thereby reducing its ability to conduct electricity. Checking a ground rod's resistance will increase the margin of safety for a home's electrical supply.

Disconnect the ground rod to be tested from the electrical service. Loosen the wire-locking collar on the rod with a wrench and remove the ground lead.

Insert the first auxiliary ground rod into the earth 33 feet from the ground rod to be tested.

Insert the second auxiliary ground rod into the earth in a straight line from the existing ground rod and the first auxiliary, 33 feet from the first auxiliary. All three rods will form a straight line with the rods equally spaced over a distance of 66 feet.

Connect the leads from the meter to the ground rods. Follow the manufacturer's instructions for your make and model of tester for correct lead placement.

Press the "On" or "Test" button. The value shown on the meter's readout will be the resistance of the ground rod.


Read the documentation for your individual meter carefully for lead placement and exact test procedures.


Exercise extreme caution while working with electricity. Read and follow all safety procedures associated with your testing device and methods.

Things You'll Need

  • 2 Auxiliary ground rods
  • Ground Resistance Tester
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About the Author

Finn McCuhil is a freelance writer based in Northern Michigan. He worked as a reporter and columnist in South Florida before becoming fascinated with computers. After studying programming at University of South Florida, he spent more than 20 years heading up IT departments at three tier-one automotive suppliers. He now builds wooden boats in the north woods.