The NEC allows equipment safety to be determined by?

The National Electrical Code (NEC) recognizes that the determination of equipment safety requires a thorough and systematic approach, which is best achieved by organizations that have the proper capabilities and qualifications for experimental testing. These organizations typically possess the necessary facilities, expertise, and testing protocols to assess various aspects of equipment safety, including performance under specific conditions, compliance with safety standards, and reliability.

Using an appropriately equipped and qualified organization ensures that the testing is conducted in a manner that adheres to established safety and performance guidelines. Such organizations are often recognized by regulatory bodies and have a track record of conducting reliable tests, making their findings critical in establishing safety standards for electrical equipment.

This approach complements the regulatory framework set forth in the NEC, which aims to enhance public safety through rigorous evaluation processes. As for the other choices, while examiners, authority figures, or local boards may have valuable input, they do not necessarily possess the specialized training and resources required for comprehensive equipment safety evaluation that organizations qualified for experimental testing have.