We generally route the cabling so that it is not directly above the rows of florecent lights. If it does go over the light fixtures, we aim for 18" of clearance above the fixtures (luminaires according to the new electrical code).
Good Luck! It is only my opinion, based on my experience and education...I am always willing to learn, educate me!
Daron J. Wilson, RCDD
daron.wilson@lhmorris.com