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 MIL-HDBK-419A
Largereductions in the resistance to earth of the individual ground electrodes may be expected after chemical
treatment has been applied to the earth. The initial effectiveness of chemical treatment is greatest where the
soil is somewhat porous because the solution permeates a considerable volume of earth and increases the
effective size of the electrode. In compact soils, the chemical treatment is not as immediately effective
because the material tends to remain in its original location for a longer period of time.
The effectiveness of chemical treatment in lowering the resistance of a ground rod is illustrated by Figures
2-24 and 2-25. Chemical treatment achieves a significant initial reduction of resistance and further stabilizes
the resistance variations. It also limits the seasonal variation of resistance and, additionally, lowers the
freezing point of the surrounding soil.
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Figure 2-24. Effect of Chemical Treatment on Resistance of Ground Rods
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Figure 2-25. Seasonal Resistance Variations of Treated and Untreated Ground Rods
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