What does the NEC mean when it uses the word "approved" related to installations?

In the context of the National Electrical Code (NEC), the term "approved" specifically refers to the acceptance of materials, methods of construction, and installations by the authority having jurisdiction (AHJ). The AHJ is typically a local inspector or building code enforcement agency that determines whether a particular installation meets the necessary safety, reliability, and regulatory standards set forth by relevant codes and regulations. An installation deemed "approved" indicates that it complies with these standards and has received the necessary permission to proceed.

The other options do not align with the context in which "approved" is used in the NEC. Aesthetic standards are subjective and not a criterion for safety or compliance in electrical installations. Similarly, the idea of being provided free of charge does not pertain to the approval process. Lastly, while compliance with international standards can be important in broader contexts, the NEC's focus is primarily on local regulations as interpreted by the jurisdictional authority. Thus, "acceptable to the authority having jurisdiction" is the key concept that captures the meaning of "approved" in this context.