S.C. Code Regs. § § 117-320.1
Where property purchased in another state and used outside the state of South Carolina, is later brought into the state for use, storage or consumption in South Carolina, the use tax will apply unless the following conditions are conclusively established: (1) That the property when purchased was intended for a bona fide use outside the state of South Carolina; (2) That the first actual use of the property was outside the state of South Carolina; and (3) That the first actual use of the property was substantial and constituted the primary use for which the property was purchased.
The responsibility for proof rests upon the purchaser and until the above facts are established to the satisfaction of the department, it will be presumed that the use of such property in South Carolina is subject to a use tax.
(See, however, Section 12-36-1320 for a special imposition of the tax on transient construction equipment.)
S.C. Code Regs. § 117-320.1