S.C. Code Ann. § 58-1-50: Interest paid with refund of excess charges not to constitute cost basis for rate-making.

Notwithstanding any other provision of law, any public utility as defined in item (3) of Section 58-5-10, any telephone utility, and any electrical utility whose rates are subject to regulation by the Public Service Commission, when putting a proposed rate increase into effect under bond in the manner authorized by law, shall not be permitted to include as part of its rate base any interest expenses paid to customers on refunds which are required when the rate increase is not approved either in whole or in part.