I don't know if a ballast capable of driving more than two 55w PCs exists. The one I have is a Sylvania/Osram Pentrom 54PHO 2-lamp model. It drives two Osram Dulux 55w bulbs. Take a look at http://www.sylvania.com/ballast/phops.htm I guess you should be able to order them at you local lightning supplier. -Ivo Busko Baltimore, MD