S.C. Code Ann. § 56-5-5150

When a vehicle is towing another vehicle on a public road or highway, the towing vehicle must be attached to the towed vehicle by a safety chain, cable, or equivalent device in addition to the regular drawbar, tongue, trailer hitch, or other connection. The safety connections or attachments must be of sufficient strength to maintain connection of the towed vehicle to the pulling vehicle under all conditions while the towed vehicle is being pulled by the towing vehicle. The provisions of this section do not apply to vehicles using a hitch known as a fifth wheel and kingpin assembly.