When grounding in shallow sandy or gravelly soil, how deep should trenches be where conductors are laid?

The correct choice regarding the depth of trenches for laying conductors in shallow sandy or gravelly soil is typically 1-2 feet. This depth is sufficient for grounding systems in these types of soils because sandy and gravelly soils often have better conductivity compared to compacted clay or rock.

When conducting grounding installations, the goal is to ensure that the grounding electrodes achieve low resistance to ground. In sandy or gravelly environments, the nature of the soil allows for effective grounding at shallower depths compared to more dense soils. Therefore, a trench depth of 1-2 feet is generally adequate to maintain the necessary electrical contact with the ground while also being practical for installation purposes.

For deeper trenching, while it could yield slightly lower resistance, it often becomes impractical in terms of labor and cost. Additionally, the moisture content and other environmental factors play a significant role in grounding efficiency, and since sandy or gravelly soils can drain moisture well, the shallower depth tends to still fulfill safety and regulatory requirements.