N.Y.C. Admin. Code § 24-407: § 24-407 Underground electrical conductors; Manhattan and the Bronx.

Any company, operating or intending to operate electrical conductors in the boroughs of Manhattan and the Bronx, if it shall desire or be required to place its conductors or any of them underground in any of the streets of such boroughs, must remove such conductors from the surface of such streets, when duly authorized so to do. It shall be obligatory upon such company to file with the commissioner of transportation a map or maps, made to scale, showing the streets which are desired to be used for such purpose, and giving the general location, dimensions and course of the underground conduits desired to be constructed. Before any such conduits shall be constructed, it shall be necessary to obtain the approval of such commissioner of transportation of the plan of construction proposed by such company. The commissioner of transportation has and shall have power to require that the work of removal and of constructing every such system of underground conductors shall be done according to such plan so approved, subject at all times to such modifications as shall be made by him or her from time to time, and subject also to such rules and regulations as may be promulgated by him.