All franchises granting the right of occupancy of any proportion of the streets of the City for work of public utility and service, shall be granted by the Council, but no such franchise shall hereafter be granted except under the following restrictions and conditions:
No franchise shall be granted, except at the time of granting it, bond be made to the City, providing that the grantee shall indemnify the City against all damages caused by construction, maintenance or operation of such works; all reasonable additional provisions and conditions may be made for the protection of the public, necessary damage or inconvenience by reason of the construction, maintenance or operation thereof.
No grant of a franchise for the extension of, or an addition to, any line of work on public service through, over or under any additional street or territory of the City, shall be made for a period extending beyond the time limit for the expiration of the franchise, if the principal work is one granted before this act goes into effect and not limited as to time; any franchise granted for an extension or addition thereto shall nevertheless be made subject to the conditions hereof, including a time limit of not exceeding fifty years.