What must be done when cables or nonmetallic raceways are installed underground?

When cables or nonmetallic raceways are installed underground, the requirement for them to be installed in close proximity ensures that they are adequately protected while reducing the risk of damage from external factors such as moisture, soil movement, or potential digging by others. This practice helps maintain safety standards and minimizes the risk of accidental contact or breaches in insulation that could lead to power outages or electrical hazards.

The electrical code requires specific measures for underground installations to ensure that the conductors are reliable and safe. By installing these elements in close proximity, it not only promotes ease of installation but also enhances accessibility for future maintenance and modifications. This practice aids in maintaining the integrity of the electrical system and helps prevent malfunctions that could arise from improper installation.

In contrast, options involving painting or insulation alone do not address the key concerns related to protecting the cables in an underground environment. The use of metal raceways is not universally necessary for all installations, particularly when properly rated nonmetallic raceways are documented for underground use.