S.C. Code § 29-1-10
No mortgage or deed having the effect of a mortgage or other lien shall constitute a lien upon any real estate after the lapse of twenty years from the date for the maturity of the lien. However, if the holder of the lien shall, at any time during the continuance of the lien, cause to be recorded upon the record of that mortgage or deed having the effect of a mortgage or other lien a note of some payment on account or some written acknowledgment of the debt secured thereby, with the date of the payment or acknowledgment, the mortgage or deed having the effect of a mortgage or other lien shall be, and shall continue to be, a lien for twenty years from the date of the record of that payment on account or acknowledgment. When there is no maturity stated or fixed in the mortgage or the record of the mortgage, then the provisions hereof are applicable from the date of that mortgage and that mortgage shall not constitute a lien after the lapse of twenty years from the date thereof. Notwithstanding the above provisions of this section, any mortgage or other instrument which by its terms creates a lien upon any real property interest held by a gas or electrical utility or electric cooperative shall continue to constitute a lien thereon until satisfied or released of record regardless of whether or not the instrument states a maturity date.
Any mortgage or other instrument executed or modified of record after the effective date of this paragraph which affects a lien upon any real property interest held by a gas or electrical utility or electric cooperative and is intended to take advantage of the provisions of this section shall state on its face that the lien continues until satisfied or released of record regardless of whether or not the instrument states a maturity date, and shall also state on its face that it is subject to the provisions of this section.
S.C. Code § 29-1-10
1993 Act No. 141, Section 5, effective June 14, 1993, provides as follows:
"SECTION 5. The provisions provided for gas or electrical utilities or electric cooperatives in Sections 29-1-10, 29-3-50(B), 29-3-80, and 29-3-90 of this act shall be construed as cumulative authority and shall not be construed to impliedly repeal any existing laws affecting mortgages and liens of gas or electrical utilities or electric cooperatives."