Bus system

A bus duct including a plurality of bus bars stacked in substantially parallel flat-to-flat relationship within a housing, said bus bars having a joining means external of said housing, said housing comprising a first pair of walls each disposed one on either side, parallel to and longitudinally along said bus bars and a second pair of walls disposed transversely and longitudinally of said bus bars and fixed to said first pairs of walls to define a cavity within which said bus bars are accommodated, said first pair of walls and said bus bars being electrically insulated one from another by individual interposed sheets of separate insulating material, said second pair of walls and said bus bars being electrically insulated one from another by resilient insulation means disposed between the plurality of bus bars and the second pair of walls, each of said first pair of walls additionally including a plurality of integrally formed outwardly projecting longitudinally disposed cooling fins, said bus bars, insulating material of said interposed sheets and the resilient insulation means, and first pair of walls being held in intimate contact with one another to provide conductive heat transfer from said bus bars to said cooling fins and so that said bus bars are rigidly held along substantially their entire length by said housing.