N.C. Gen. Stat. § 143-130: Allowance for convict labor must be specified.

In cases where the board or governing body of a State agency or of any political subdivision of the State may furnish convict or other labor to the contractor, manufacturer, or others entering into contracts for the performance of construction work, installation of apparatus, supplies, materials or equipment, the specifications covering such projects shall carry full information as to what wages shall be paid for such labor or the amount of allowance for same. (1933, c. 400, s. 2; 1967, c. 860.)