S.C. Code § 58-5-410
A public utility providing natural gas distribution service, in its discretion and at anytime, may elect to have the terms of this article apply to its rates and charges for gas distribution service, on a prospective basis, by filing a notice of the election with the commission and on the same day and by the same means serving a copy on the Office of Regulatory Staff. Upon receipt of notice of the election, the commission shall proceed to make the findings and establish the ongoing procedures required for adjustments in base rates to be made under this article. In carrying out the procedures established by this article with respect to such an election, the commission shall rely upon and utilize the approved rates, charges, revenues, expenses, capital structure, returns, and other matters established in the public utility's most recent general rate proceeding pursuant to Section 58-5-240; provided, however, that the most recent order must have been issued no more than five years prior to the initial election to come under the terms of this article. A public utility may combine an election under this article with the filing of a rate proceeding pursuant to Section 58-5-240 and the commission shall include the findings required by this article in its rate orders issued in the Section 58-5-240 proceedings, and the election shall remain in effect until the next general rate proceeding.
S.C. Code § 58-5-410