Under which condition are underground cables and conductors required to be installed in a raceway?

Underground cables and conductors must be installed in a raceway if they are buried under a building to ensure protection against potential damage from physical impacts, moisture, and other environmental factors. This requirement helps maintain the integrity of the electrical system and adheres to safety regulations. The raceway provides a robust protective conduit for the cables, reducing risks related to maintenance, accidental disturbance, and long-term degradation due to soil conditions or structural movements.

Other contexts, such as being run along exterior walls or in public access areas, have different guidelines and may address visibility, access, and exposure to the elements rather than providing the same level of physical protection required when cables are buried under a building. Additionally, the specification regarding conduits less than 6 inches in diameter does not relate directly to the necessity of raceways for underground installation, as it focuses more on the size of the conduit rather than the associated installation conditions.