S.C. Code Ann. § 37-4-210: What constitutes disability.

Disability shall not be defined more restrictively than the inability of the insured to engage in his own occupation during the first year of disability or for the length of the benefit period if less than one year. After the first year of disability, disability shall not be defined more restrictively than the inability of the insured to engage in the substantial duties of any gainful occupation for substantially equivalent remuneration to the insured's own occupation. Substantially equivalent remuneration means not less than seventy-five percent of the insured's base wage, exclusive of overtime and bonus, as of the date disability commences.