S.C. Code § 56-5-4095
An official of the Department of Transportation designated by the secretary, in his discretion, upon application in writing and good cause being shown, may issue to a vehicle a permit in writing authorizing the applicant to operate or move upon the state's public highways a motor vehicle and loads for transporting not more than two modular housing units or sectional housing units if the total length of the vehicle, including the load, does not exceed the length presently authorized by law and regulation for the transporting of mobile homes. No permit may be issued to any vehicle whose operation upon the public highways of this State threatens the safety of others or threatens to unduly damage a highway or any of its appurtenances.
S.C. Code § 56-5-4095