Whenever a public utility incorporated under the laws of this state shall apply to the commission for authority to issue any stock requiring the approval of the commission, the stockholders shall not become individually liable for debts and contracts of the corporation under N.H. Rev. Stat. § 296:30, if the amount of stock which the commission authorized the corporation to issue upon any such application is paid in and a certificate of the treasurer and a majority of the directors to that effect is executed, filed and recorded in the manner provided by N.H. Rev. Stat. § 296:30 within 90 days after the filing in the office of the secretary of state of the order of the commission authorizing the issue of such stock; provided, that, in cases where such stock is an increase of prior capital, the whole amount of the prior capital as theretofore fixed and limited by the corporation, or so much thereof as the stockholders have voted to issue, or as the commission has authorized to be issued, has also been paid in and that the certificate so filed by the treasurer and directors shows that fact.