Pub. Util. Code, § 2906

“Powers of control” means all powers of control vested in a municipal corporation to supervise and regulate (a) the relationship between public utilities and their present or prospective customers, consumers, or patrons. The term does not include the powers of control vested in any municipal corporation to supervise and regulate the relationship between such public utilities and the general public in matters affecting the health, convenience, and safety of the general public, including matters such as the use and repair of public streets by any public utility, the location of the poles, wires, mains, or conduits of any public utility, on, under, or above any public streets, and (b) the speed of common carriers operating within the limits of the municipal corporation.