N.C. Gen. Stat. § 122C-312
Inmates in the custody of the Division of Prisons of the Department of Adult Correction may seek voluntary admission to State facilities for the mentally ill or substance abusers. The provisions of Part 2 of this Article shall apply except that an admission may be accomplished only when the Secretary and the Secretary of the Department of Adult Correction jointly agree to the inmate's request. When an inmate is admitted he shall be discharged in accordance with the provisions of Part 2 of this Article except that an inmate who is ready for discharge, but still under a term of incarceration, shall be discharged only to an official of the Division of Prisons of the Department of Adult Correction. The Division of Prisons of the Department of Adult Correction is responsible for the security and cost of transporting inmates to and from facilities under the provisions of this section.
N.C. Gen. Stat. § 122C-312