PURPOSE: An enclosed switchboard is provided to maintain insulation between a bus bar and a housing by surrounding the outer circumference of the bus bar with the wall through bushing. CONSTITUTION: First and fourth housings have the rectangular parallelepiped shape. A hinged door is formed in one side of the first to fourth housing. The second housing(3) is detachably combined in the first housing(1). One side of the second housing is contacted with the circumference of the first housing. The third housing is detachably combined in the second housing. One side of the third housing is contacted with the circumference of the second housing. The fourth housing is detachably combined in the first or third housing. One side of the fourth housing is contacted with the circumference of the first or third housing. The first housing includes a bus bar and a tube insulator. The bus bar receives high voltage of 22.9 kV. The tube insulator is protruded from the inner circumference of the first housing to support the bus bar.
