N.C. Gen. Stat. § 117-16
The corporate purpose of each corporation formed hereunder shall be to render service to its members only, and no person shall become or remain a member unless such person shall use energy supplied by such corporation and shall have complied with the terms and conditions in respect to membership contained in the bylaws of such corporation: Provided, that such terms and conditions of membership shall be reasonable; and provided further, that no bona fide applicant for membership, who is able and willing to satisfy and abide by all such terms and conditions of membership, shall be denied arbitrarily, or capriciously, or without good cause. With respect to the members of an electric membership corporation whose principal purpose is to furnish or cause to be furnished bulk electric supplies at wholesale, the word "use" as used in this section shall also mean either "use and purchase" or "purchase" solely, as the case may be, and the words "supplied by" shall also mean "supplied for the account of". With respect to an electric membership corporation whose principal purpose is to furnish or cause to be furnished bulk electric supplies at wholesale, it shall be lawful for such corporation to enter into joint arrangements with other power supply entities, including but not limited to investor-owned public utilities and bodies politic, for the purchase and sale of bulk power supplies and bulk power services and for the joint ownership of bulk power supply properties.
N.C. Gen. Stat. § 117-16