Cal. Pub. Util. Code § 1793
Upon the filing of the petition the court shall enter an order directing the witness to appear before the court at a time and place fixed in the order and show cause why he has not attended and testified or produced said papers before the commission. The time fixed shall not be more than 10 days from the date of the order. A copy of the order shall be served upon the witness. If it appears to the court that the subpena was regularly issued by the commission or a commissioner, the court shall thereupon enter an order that the witness appear before the commission or commissioner at the time and place fixed in the order, and testify or produce the required papers, and upon failure to obey the order, the witness shall be dealt with as for contempt of court. The remedy provided in this section is cumulative, and shall not be construed to impair or interfere with the power of the commission or a commissioner to enforce the attendance of witnesses and the production of papers, and to punish for contempt in the same manner and to the same extent as courts of record.
Ca. Pub. Util. Code § 1793