The purpose of NEMA standards
A standard of the National Electrical Manufacturers Association defines a product, process, or procedure with reference to one or more of the following:
The service for which it is designed
It is NEMA’s belief that standards play a vital part in the design, production, and distribution of products destined for both national and international commerce. Sound technical standards benefit the user, as well as the manufacturer, by improving safety, bringing about economies in product, eliminating misunderstandings between manufacturer and purchaser, and assisting the purchaser in selecting and obtaining the proper product for his particular need.