A busway joint pack includes a pair of opposing phase connector plates, a first insulating sheet, a second insulating sheet, a first side panel, and a second side panel. The busway joint pack passively transfers thermal energy generated in its core to an exterior housing such that the thermal energy is dissipated or transferred to the surrounding environment, which reduces the internal temperature of the joint pack. The first and the second insulating sheets are positioned and selected with a particular thermal resistance and dimensions such that a portion of the thermal energy generated in the core of the busway joint pack is transferred from the pair of opposing phase connector plates to the external housing.