California Code, Elections Code - ELEC § 16641

If the proceeding is in a county where there is more than one superior court judge, the judge to whom the case is assigned shall notify the presiding judge forthwith of the number of judges which he or she deems necessary to participate in order to finish the contest in time to print the ballots for the final election. The presiding judge shall forthwith designate as many judges as are necessary to completion of the contest, by order in writing and thereupon all of the judges so designated shall participate in the recount of the ballots and the giving of judgment in the contest in the manner specified in this article.