Re: Rewiring a light fixture to use a power plug
All flo. fixtures with 3 wire ballasts were wired Black to Black on ballast, White to white on ballast and to one pin on lamp, Red to other pin on lamp. I'm not saying that is the only configuration just that it is all that I've worked on. Do as Ernie says and check the ballast there is almost always a wiring diagram on it. Oh and you would connect your ground wire to a screw through the body of the fixture.
Be sure you live your life, because you are a long time dead.-Scottish Proverb