California Code, Public Utilities Code - PUC § 312

The commission and each commissioner may issue writs of summons, subpenas, warrants of attachment, warrants of commitment, and all necessary process in proceedings for contempt, in like manner and to the same extent as courts of record. The process issued by the commission or any commissioner, extends to all parts of the State and may be served by any person authorized to serve process of courts of record, or by any person designated by the commission or a commissioner. The person executing any such process shall receive such compensation as is allowed by the commission, not to exceed the fees prescribed by law on August 8, 1915, for similar services, and such fees shall be paid in the same manner as provided in this part for payment of the fees of witnesses.