Quality earth rods are commonly made from either solid copper, stainless steel or copperbonded steel.

The copperbonded steel cored rod is by far the most popular, due to its combination of strength, corrosion resistance, and comparatively low cost.

Solid copper and stainless steel rods offer a very high level of corrosion resistance at the expense of lower strength and higher cost. However solid copper can be used in areas that are highly corrosive.

Diameter of the Rod…… does NOT have much to do with earth resistance reduction

One common misconception is that the diameter of the rod has a drastic effect on lowering earth resistance. This is not true!

As the graphs shows, you only lower the resistance value by 9.5 percent by doubling the diameter of the rod (which means increasing the weight and the cost of the rod by approximately 400 percent!)

Thus the rationale is: use the most economical rod that soil conditions will allow you to drive. This is one of the ways to ensure that you don’t waste money on over-dimensioned rods.

Victor Oyedu, FNSE, FNIEEE, CPQ.
Power Quality and Energy Management Specialist.
Publisher at Afrienergyonline.com &
CEO, FullSpectrum Energy Solutions Limited, Nigeria.