Filing schedules in business office. (1) A copy of so much of all schedules, including schedules of joint rates and charges, as the Public Utility Commission deems necessary for the use of the public shall be printed in plain type and kept on file in every business office of such public utility, open to the public, and in such form and place as to be readily accessible to the public for convenient inspection

(2) Copies of all new schedules shall be filed in every business office of such public utility 30 days prior to the time the schedules are to take effect, unless the commission prescribes a shorter time. [Amended by 1971 c.655 §73]