The town is empowered to permit and regulate, or to prohibit, the erection of poles and wires for electric telegraph or telephone service or the laying of any kinds of pipes in the streets or alleys of the town, and to prescribe, assess and collect annual or other periodical charges for the doing of any such things under permits hereafter granted; and the power to require the owners or operators of any such electric light, telephone or telegraph lines to change the location of any of their poles whenever the council deems any such change expedient; and to require all wires or cables carrying electric current, whether heretofore or hereafter installed to be placed in suitable conduits, underground, in the discretion of the council; provided that none of the powers above enumerated shall be exercised in a manner inconsistent with the provisions of any franchise granted by the town.