Which statement is an example of mandatory language in the NEC®?

The statement that "terminals for aluminum connections shall be identified" serves as an example of mandatory language in the National Electrical Code (NEC). This language indicates a requirement that must be adhered to, emphasizing the necessity of proper identification for terminals used with aluminum conductors. The use of the term "shall" is critical here as it denotes an obligation or a stipulation that must be followed, reflecting the NEC's emphasis on safety and compliance in electrical installations.

In contrast, other statements present softer language or subjective criteria. For instance, describing terminals as "aesthetically pleasing" does not impose a clear requirement, and thus, it cannot be deemed mandatory. Similarly, while saying that "terminals for more than one conductor must be insulated" suggests a guideline, it lacks the definitive obligation that "shall" conveys. Lastly, the directive regarding inspections might imply importance but does not possess the same mandatory clarity established by the phrase concerning aluminum connections.

This distinction is vital for interpreting the NEC and understanding which regulations must be strictly followed to ensure safety and compliance in electrical work.