What is the typical distance at which direct buried cables collect ground strikes, determined by soil resistance?

The correct answer is based on the understanding of how ground strikes and soil resistance interact with buried cables. When a ground strike occurs, the electrical energy seeks a path of least resistance to ground. The distance at which this energy can affect buried cables is influenced by the soil characteristics, including moisture content and composition.

The range identified (6.6' to 19.7') is appropriate as it reflects typical soil resistance values. This means that ground strikes can affect cables buried within this distance from the surface, especially in soils with varying conductive properties. As such, understanding this range is critical for designing protection measures around direct buried cables, ensuring they are sufficiently shielded from potential electrical surges caused by lightning strikes or other electrical phenomena.

Other ranges either extend beyond the practical reach of typical lightning-induced currents in common soil types or do not adequately account for the resistance impact on energy dispersal into the ground. This makes the given range both practical and relevant for OSP design considerations.