S.C. Code § 56-5-4900
Sections 56-5-4850 to 56-5-4890 do not apply to trailers, not exceeding eight thousand pounds gross weight, which are pulled behind farm tractors or trucks and used in the transportation of farm products and articles to and from farms. These trailers may not exceed a speed of twenty miles an hour. However, farm trailers exceeding eight thousand pounds gross weight, excluding gooseneck-type trailers, which are not equipped with brakes must be pulled by tow vehicles whose empty vehicle weight is at least one-half of the farm trailer's gross vehicle weight. These trailers may not exceed a speed of thirty miles an hour and may only be pulled in clear weather conditions.
Two small tobacco trailers may be pulled in tandem if:
Notwithstanding any other provision of this section or of this chapter, all farm and tobacco trailers when towed must be secured by a pintle hook, spring-load latch, safety lock hitch pin, or equivalent mechanism and also must be equipped with and shall have in use safety chains secured by a spring-loaded latch or other mechanism to ensure positive closure under loaded, operating conditions when the trailers are used to haul farm products and articles on the roads, streets, or highways of this State.
S.C. Code § 56-5-4900