According to NFPA 70, how must direct buried cables be arranged?

The arrangement of direct buried cables must be such that it prevents damage when the ground settles. This is crucial because ground movement can occur due to various factors like temperature changes, moisture content, and soil composition. If the cables are positioned in a way that does not accommodate settling or movement, there is a risk that they might become damaged, which can lead to service interruptions, safety hazards, or costly repairs.

While other options may seem plausible, they do not address the fundamental requirement of ensuring the longevity and safety of the installation. For instance, while coils might allow for expansion, they do not inherently mitigate the risk of damage from ground settling. Similarly, using protective conduit can provide benefits but may not always be feasible or necessary depending on the installation context. Arranging cables in a straight line could contradict the need to allow for adaptability with ground conditions. Therefore, the best practice according to NFPA 70 is to place direct buried cables in a manner that accounts for potential ground movement to maintain their integrity.