Cal. Pub. Util. Code § 830

No public utility shall assume any obligation or liability as guarantor, endorser, surety, or otherwise in respect of the securities of any other person, firm, or corporation, when such securities are payable at periods of more than 12 months after the date thereof, without having first secured from the commission an order authorizing it so to do. Every such assumption made other than in accordance with the order of the commission authorizing it is void.