How are the three bushings on a distribution step regulator labeled?

The labeling of the three bushings on a distribution step regulator as Source (S), Load (L), and Neutral/Source Load (SL) is recognized as standard practice in the electrical distribution industry. Each label corresponds to a specific function within the operation of the regulator, which is essential for understanding how the step regulator manages voltage levels in a distribution system.

The "Source" bushing is where the incoming power supply connects, making it crucial for directing energy into the system. The "Load" bushing connects to the load side where electricity is delivered to the consumers or distribution lines. The "Neutral/Source Load" bushing serves a dual purpose, either connecting back to the neutral point of the system or providing a path for balancing the load when required. This labeling convention ensures clear communication among linemen and other electrical personnel regarding the configuration and operational functions of the regulator, facilitating safe and efficient work practices.

Other choices, while they may include terms related to electrical installations, do not accurately reflect the standardized labeling or commonly accepted terminology associated with distribution step regulators. Therefore, the use of terms defined in choice B promotes both clarity and safety in the lineman's work.