South Carolina Code 56-3-120. Exemptions from registration and licensing requirement
(1) a vehicle driven, operated, or moved upon a highway pursuant to the provisions of this chapter relating to nonresidents or under temporary permits issued by the department as authorized;
(2) any implement of husbandry, including a knuckleboom loader mounted on a trailer or straight truck, whether of a type otherwise subject to registration and license which only incidentally is operated or moved upon a highway;
(3) a special mobile equipment vehicle which only occasionally is moved over a highway and special mobile equipment vehicle of the State or its departments, agencies, or political subdivisions;
(4) a vehicle owned and operated by the government of the United States; and
(5) a trailer or semitrailer commonly used in combination with a large commercial motor vehicle, as defined in § 12-37-2810, for which trailer or semitrailer the fee imposed pursuant to § 12-37-2860 is paid and applicable registration requirements provided pursuant to Article 23, Chapter 37 of Title 12, are met, and a distinctive permanent plate has been issued pursuant to § 12-37-2860.
(6) firefighting vehicles that are publicly owned by the state or a county, municipality, or special purpose district as follows:
(a) motorized firefighting vehicles that carry a pump or water tank in excess of three hundred gallons;
(b) motorized firefighting vehicles containing a hydraulically operated ladder; and
(c) specialized support vehicles that specifically transport equipment utilized for rescue operations, hazardous materials response, wildfire emergencies, breathing air refill support, and incident command.