The provisions of Sections 37-4-7 through 37-4-12 shall not apply to notes issued by a utility for the proper purposes and not in violation of law, payable at a period of not more than two years from the date thereof, and aggregating (together with all other outstanding notes of a maturity of two years or less) not more than five percent of the tangible fixed capital as defined in the accounting classification as prescribed by the commission, and shall not apply to like notes issued by a utility, payable at a period of not more than two years from the date thereof, to pay, retire, discharge or refund, in whole or in part, any such note or notes, and shall not apply to renewals thereof from time to time, not exceeding in the aggregate six years from the date of the issue of the original note or notes so renewed or refunded. No such notes payable at a period of not more than two years from the date thereof shall, however, in whole or in part, directly or indirectly, be paid, retired, discharged or refunded by any issue of securities of another kind of any term or character, or from the proceeds thereof without the approval of the commission. Within 10 days after the making of any such notes, so payable at periods of not more than two years from the date thereof, the utility issuing the same shall file with the commission a certificate of notification, in such form as may from time to time be determined and prescribed by the commission, setting forth as nearly as may be the same matters as those required in respect of application for authority to issue other securities.