When is a system permitted to be grounded according to NEC® Sections 250.20, 250.21, and 250.22?

The correct choice is based on the principles outlined in the National Electrical Code (NEC) sections regarding grounding requirements. NEC Sections 250.20, 250.21, and 250.22 provide specific guidelines that dictate when grounding is necessary, emphasizing the importance of the type of electrical system and its intended usage.

Grounding is fundamentally influenced by the characteristics of the electrical system, such as whether it is a separately derived system, the voltage level, and how the system is utilized in practice. For example, solidly grounded systems have different requirements compared to ungrounded systems. Furthermore, the nature of the loads connected to the system can also determine whether grounding is beneficial or necessary to enhance safety and operational effectiveness.

By establishing the need for grounding based on system type and usage, these NEC sections ensure that appropriate safety measures are in place to protect personnel and equipment. This approach assists in minimizing electrical hazards and promoting reliable operation, adhering to the overarching safety philosophy behind the NEC. Therefore, understanding the context of these sections is essential for electricians and engineers to ensure compliance and safety in electrical installations.