Equipment that is labeled or identified for a use must be installed according to:

The reason the manufacturer's instructions is the correct choice lies in the principle of ensuring safe and proper use of electrical equipment. When equipment is specifically labeled or identified for a particular use, it indicates that the manufacturer has tested and approved the equipment for that function under specified conditions. Following the manufacturer’s installation instructions is crucial because these guidelines are based on safety standards, performance requirements, and specific operating conditions that need to be met to avoid hazards such as electrical shock, fire, or equipment malfunction.

While national safety guidelines, code specifications, and local electrical codes are important, they serve broader regulatory and safety functions. They set general criteria for electrical installations and practices to ensure a baseline level of safety. However, they may not account for all the specific nuances or unique requirements of a particular piece of equipment. Therefore, adherence to the manufacturer's instructions takes precedence as it aligns with the original design parameters and safety assurances set by the manufacturer.