Cal. Public Utilities Code § 240319

(a) The commission may provide for the issuance, sale, or exchange of refunding bonds to redeem or retire any bonds issued by the commission upon the terms, at the times and in the manner which it determines. (b) Refunding bonds may be issued in a principal amount sufficient to pay all, or any part of, the principal of the outstanding bonds, the premiums, if any, due upon call and redemption thereof prior to maturity, all expenses of the refunding, and either of the following: (1) The interest upon the refunding bonds from the date of sale thereof to the date of payment of the bonds to be refunded out of the proceeds of the sale of the refunding bonds or to the date upon which the bonds to be refunded will be paid pursuant to call or agreement with the holders of the bonds. (2) The interest upon the bonds to be refunded from the date of sale of the refunding bonds to the date of payment of the bonds to be refunded or to the date upon which the bonds to be refunded will be paid pursuant to call or agreement with the holder of the bonds. (c) The provisions of this chapter for the issuance and sale of bonds apply to the issuance and sale of refunding bonds.