250.81—Exempted transactions.
Unless otherwise expressly provided, the rules, regulations, and orders of the Commission pertaining to the performance of services or construction or the sale of goods shall not be applicable to the sale of water, telephone service, transportation, or a similar commodity or service, the sale of which is normally subject to public regulation, or to the furnishing of services, construction, or goods, to a customer incidentally to such a sale; and such transactions shall be exempt from the provisions of section 13 of the Act (49 Stat. 825; 15 U.S.C. 79m) and the rules and regulations thereunder: Provided, That, where any such transaction is with an associate company in its capacity as a consumer, comparable services, construction, or goods are offered to customers other than associate companies on terms which are comparable having due regard to any differences of quality or quantity.