Modular insulation system

A method and modular insulation system for an electrical equipment enclosure having multi-phase bus bars and a mounting base for mounting electrical equipment. The insulation system includes a plurality of components including a plurality of side isolation barriers with each barrier defining at least one slot proximate one edge of the barrier and having at least one tab along another edge of the barrier. A side barrier adapter is configured to engage the isolation barrier and to engage the mounting base. An inner isolation barrier is configured to isolate at least two of the vertical bus bars and couple to the mounting base. A vertical bus rearwall defining a plurality of slots proximate at least two edges of the cover is fastened to the inner isolation barrier. A plurality of corner connectors is configured to engage one of the cover slots and the side isolation barrier slots.