Which sheet material is best for electrical insulation?

For rigid electrical insulation supplied as sheet, the main choices are phenolic paper (SRBP) for general switchgear and busbar insulation, epoxy cotton (SRBF) where mechanical strength is also needed, and woven glass epoxy for the highest voltage and temperature duty. All are cut to size and machined to close tolerances. The most widely used switchgear sheet grade is on the paper laminates (SRBP) range.