The erection, construction, alteration, or maintenance by public utilities or City departments, boards, or commissions, of overhead, surface or underground gas, electrical steam, or water, distribution or transmission systems, collection, communication, supply or disposal systems, including mains, drains, sewers, pipes, conduits, tunnels, wires, cables, fire alarm boxes, police call boxes, traffic signals, hydrants, poles, electrical substation, gas regulator stations and other similar equipment and accessories in connection therewith, reasonably necessary for the furnishing of adequate service by such City utility or City department, board, or commission or for the public health, safety, convenience, prosperity or general welfare, shall be exempt from the regulations of this code. Provided, however, that the installation shall conform to Federal Communications Commission and Federal Aviation Agency rules and regulations, and those of other authorities having jurisdiction.