(1)(a) In this section: 1. "Primary voltage extension" means an extension of 500 feet or more.2. "Secondary voltage extension" means an extension that is less than 500 feet.(b) The length of an extension shall be measured as the air line distance between an existing local service distribution line that normally operates at less than 35 kilovolts and the nearest point on the principal building or facility to be served by a primary voltage extension or a secondary voltage extension. (1m) No public utility, and no cooperative association organized under ch. 185 for the purpose of furnishing electric service to its members only, may: (a) Extend or render electric service directly or indirectly to the premises of any person already receiving electric service directly or indirectly from another public utility or another cooperative association.(b) Make a primary voltage extension to serve the premises of any person not receiving electric service and to which service is available from the facilities of another public utility or another such cooperative association through a secondary voltage extension, unless the other public utility or cooperative association consents to the primary voltage extension in writing or unless the commission, after notice to the interested parties and hearing, determines that the service rendered or to be rendered by the other public utility or cooperative association is inadequate and is not likely to be made adequate, or that the rates charged for service are unreasonable and are not likely to be made reasonable.(2) If a public utility is rendering electric service under an indeterminate permit to a city or village, no cooperative association may extend any new electric service to the premises of any person inside the corporate limits, existing on January 1, 1961, of the city or village without the written consent of the public utility. Within any area annexed to a city or village after January 1, 1961, in which annexed area a cooperative association or public utility, other than the public utility serving the city or village under an indeterminate permit, has electric distribution facilities at the time of the annexation, the cooperative association or other public utility may make a primary voltage extension or a secondary voltage extension in the annexed area, subject to sub. (1m). (2m) The distribution service facilities of a cooperative association or public utility rendering electric service in an annexed area under sub. (2) shall be subject to acquisition under ch. 197 by a city or village if the city or village operates or proposes to operate its own electric public utility.(3) Nothing in this section shall preclude any public utility or any cooperative association from extending electric service to its own property or facilities or to another cooperative association for resale.(4) To avoid duplication of facilities, a public utility and a cooperative association may enter into a written agreement governing the extension of electric distribution lines and the right to serve customers. The commission shall enforce an agreement if the agreement has been filed with the commission and approved by the commission as being in the public interest.(5) If an interested party files a complaint with the commission that an electric public utility or a cooperative association has made a primary voltage extension that requires approval or consent under this section without obtaining approval or consent, the commission shall hear the complaint upon notice to the interested parties. If the commission determines that the primary voltage extension was made in violation of this section, it shall order the prompt removal of the primary voltage extension.(6) A cooperative association shall be subject to the authority of the commission to enforce the provisions of this section and to issue rules and orders relating to the provisions.(7) A cooperative association shall be subject to the authority of the commission to allocate, assess and collect expenditures of the commission against a cooperative association involved in a proceeding under this section in the same manner as provided for public utilities under s. 196.85.1971 c. 125 s. 521; 1983 a. 53; 1991 a. 94. Although one utility was serving a farm, when the farm was annexed to a city and a large shopping center was built, the utility having an indeterminate permit to serve the city could not be barred from serving the area; the PSC should determine which utility should serve the area. Adams-Marquette Electric Cooperative v. PSC 51 Wis. 2d 718, 188 N.W.2d 515 (1971). The "premises of a person already receiving electrical service" refers to the premises to be served, not the person. Adams-Marquette Electric Cooperative v. PSC 51 Wis. 2d 718, 188 N.W.2d 515 (1971). The application of this section is discussed. A court's order to a utility violating this section to remove the offending line or sell it to the utility who should have provided the service was within the authority granted by sub. (5). Barron Electric Cooperative v. PSC, 212 Wis. 2d 752, 569 N.W.2d 726 (Ct. App. 1997), 97-0420.