[F]I have undertaken the task of re-wiring an (8) eight lamp fixture, which has small base sockets rated at 75w each. My first question is that:If the primary power source is 18ga. Lamp cord, after the box which is 14/2 w/grnd. What is the correct wire application? Second question: Is a separate ground wire for the fixture necessary if the box is grounded, and if so, what is the appropriate method of grounding? ?

18 gauge can be used to rewire the fixture. Ground the box, and ground the fixture using a pigtail off the ground in the box, to the spider plate or whatever bracket you use to mount your fixture with using a machine screw.