"(3) Equipment Grounding Provisions for Cords. Wetniche luminaires (lighting fixtures) that are supplied by a flexible cord or cable shall have all exposed non–currentcarrying metal parts grounded by an insulated copper equipment grounding conductor that is an integral part of the cord or cable. This grounding conductor shall be connected to a grounding terminal in the supply junction box, transformer enclosure, or other enclosure. The grounding
conductor shall not be smaller than the supply conductors and not smaller than 16 AWG.
this section spells it out pretty good