How are service conductors, underground defined?

Service conductors, underground are defined as conductors that run beneath the ground to connect directly to the main power supply. This definition emphasizes the role of these conductors in providing a safe and reliable electrical connection from the utility supply to a building or facility, ensuring that they are protected from environmental factors that might affect overhead lines.

The focus on underground conductors reflects concerns for safety, aesthetics, and reliability, as installing power lines underground can reduce the risk of damage from weather events like storms or falling trees. This installation method is especially beneficial in residential areas where visual impact and safety are priorities.

The other choices describe conductors in ways that do not accurately represent the characteristics of underground service conductors. For instance, conductors that run from the utility to the roof of a building suggest overhead wiring, while cables used exclusively for underground residential lighting are more specialized and not intended for mains power supply. Similarly, conductors for temporary power supply systems serve a transient function and do not fit the description of permanent underground service conductors.