A public utility lawfully engaged in business in this state may, with the approval of the commission but not otherwise, issue and sell its stock, bonds, notes and other evidences of indebtedness payable more than 12 months after the date thereof for lawful corporate purposes. The proposed issue and sale of securities will be approved by the commission where it finds that the same is consistent with the public good. Such approval shall extend to the amount of the issue authorized and the purpose or purposes to which the securities or the proceeds thereof are to be applied, and shall be subject to such reasonable terms and conditions as the commission may find to be necessary in the public interest; provided, however, that the provisions of N.H. Rev. Stat. Chapter 293-A shall be observed by corporations organized under the laws of this state in respect of the corporate authorization required and of other formalities to be observed.