(a) Every order made by the Commission shall be served upon the person or public utility affected thereby, within 10 days from the time the order is filed, by personally delivering or sending by certified mail a certified copy thereof to the person to be affected thereby, or in case of a public utility to any officer or agent thereof upon whom a summons may be served in accordance with the provisions of the law of this State, or to the person designated by such public utility to accept service as provided in this chapter. In any proceeding in which such person or public utility shall be represented by an attorney, service may be made upon such attorney of record.
(b) All orders of the Commission shall become effective within such reasonable time as it prescribes.