At distribution voltages, how much does the voltage drop across the earth decrease for each two to three feet?

At distribution voltages, the voltage drop across the earth decreases significantly as you move farther away from the grounding system due to the dispersion of electrical current into the earth. The principle behind this behavior is that as the distance from the grounding point increases, the resistance of the earth becomes larger, causing the voltage to drop as the electrical potential spreads out over a greater area.

In the context of the question, for every two to three feet away from the grounding point, the drop in voltage is substantial—around 50%. This reflects the concept that the earth has a resistive characteristic, and changes in distance lead to notable changes in voltage potential. The reduction in voltage is grounded in the physical properties of earth conductivity and how electrical energy dissipates into the surrounding material.

Given this understanding, the correct answer highlights the significant drop in voltage that occurs just a few feet away from the grounding point, which is an essential consideration in electrical distribution and safety practices.