These standards cover assemblies of switchgear devices such as switches@ interrupting devices@ and control@ metering@ protective and regulating equipment with associated interconnections and supporting structures. They no not apply to industrial control equipment@ communication switchboards@ switching equipment or switchboards for ships. Purpose of Standards National Electrical Manufactures Association Standards are adopted in the public interest and are designed to eliminate misunderstandings between the manufacturer and the purchaser and to assist the purchaser in selecting and obtaining the proper product for its particular need. Existence of National Electrical Manufacturers Association Standards does not in any respect preclude any member or non-member from manufacturing or selling products not conforming to the standard.