N.C. Gen. Stat. § 122C-312

Inmates in the custody of the Division of Adult Correction and Juvenile Justice of the Department of Public Safety 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 Public Safety 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 Adult Correction and Juvenile Justice of the Department of Public Safety. The Division of Adult Correction and Juvenile Justice of the Department of Public Safety is responsible for the security and cost of transporting inmates to and from facilities under the provisions of this section.