(a) Notwithstanding an order of suspension of an increase in rates, any public utility except a common carrier may, subject to the provisions of subsections (b), (c) and (d) hereof, put such suspended rate or rates into effect upon the expiration of six months after the date when such rate or rates would have become effective, if not so suspended, by notifying the Commission and its consumers of its action in making such increase not less than 10 days prior to the day when it shall be placed in effect; provided, however, that utilities engaged in the distribution of utility commodities bought at wholesale by the utility for distribution to consumers may put such suspended rate or rates, to the extent occasioned by changes in the wholesale rate of such utility commodity, into effect at the expiration of 30 days after the date when such rate or rates would become effective if not so suspended; provided that no rate or rates shall be left in effect longer than one year unless the Commission shall have rendered its decision upon the reasonableness thereof within such period. This  section to become effective July 1, 1963.

(b) No rate or rates placed in effect pursuant to this section shall result in an increase of more than twenty percent (20%) on any single rate classification of the public utility.

(c) No rate or rates shall be placed in effect pursuant to this section until the public utility has filed with the Commission a bond in a reasonable amount approved by the Commission, with sureties approved by the Commission, or an undertaking approved by the Commission, conditioned upon the refund in a manner to be prescribed by order of the Commission, to the persons entitled thereto of the amount of the excess plus interest from the date that such rates were put into effect, if the rate or rates so put into effect are finally determined to be excessive. The amount of said interest shall be determined pursuant to N.C. Gen. Stat. § 62-130(e).

(d) If the rate or rates so put into effect are finally determined  to be excessive, the public utility shall make refund of the excess plus interest to its customers within 30 days after such final determination, and the Commission shall set forth in its final order the terms and conditions for such refund. If such refund is not paid in accordance with such order, any persons entitled to such refund may sue therefor, either jointly or severally, and be entitled to recover, in addition to the amount of the refund, all court costs and reasonable attorney fees for the plaintiff, to be fixed by the court. (1933, c. 307, s. 7; 1959, c. 422; 1963, c. 1165, s. 1; 1981, c. 461, s. 2.)