S.C. Code Ann. § 24-5-350
A reserve shall serve and function as a jailer or detention officer only on specific orders and directions of the director. To maintain status, a reserve shall perform a minimum logged service time of ten hours a month or thirty hours a quarter.
No reserve detention officer shall perform any jailer or detention officer duties except under the direct supervision of a full-time jailer or detention officer. A reserve shall not assume full-time duties of jailers or detention officers without complying with the requirements for full-time jailers and detention officers.
A department utilizing reserves shall have at least one full-time officer as a coordinator-supervisor who must be responsible directly to the director.