N.Y. Pub. Serv. Law § 71
Upon the complaint in writing of the mayor of a city, the trustees of a village, the town board of a town or the chief executive officer or the legislative body of a county in which a person or corporation is authorized to manufacture, convey, transport, sell or supply gas or electricity for heat, light or power, or upon the complaint in writing of not less than twenty-five customers or purchasers of such gas or electricity, or upon the complaint in writing of the department of state, or upon a complaint of a gas corporation or electrical corporation supplying or transmitting said gas or electricity, as to the illuminating or heating power, purity or pressure or the rates, charges or classifications of service of gas, the efficiency of the electric incandescent lamp supply, the voltage of the current supplied for light, heat or power, or the rates charged or classification of service of electricity sold and delivered in such municipality, or as to the extent or duration of a disruption in gas or electricity service, the commission shall investigate as to the cause for such complaint. When such complaint is made, the commission may, by its agents, examiners and inspectors, inspect the works, system, plant, devices, appliances and methods used by such person or corporation in manufacturing, transmitting and supplying such gas or electricity, andd may examine or cause to be examined the books and papers of such person, or corporation pertaining to the manufacture, sale, transmitting and supplying of such gas or electricity. The form and contents of complaints made as provided in this section shall be prescribed by the commission. Such complaints shall be signed by the officers, or by the customers, purchasers or subscribers making them, who must add to their signatures their places of residence, by street and number, if any. The commission shall publish the form and instructions for completing the form on the commission's website.
N.Y. Pub. Serv. Law § 71