Explanation of the type designation

The type designation of outdoor bushing insulators consists of four letters and the corresponding number:

AT = Bushing insulator
B, C = Designation indicating the permissible breaking force of the insulator body
E = Outdoor insulator, shed type
10, 20, 30 = Rated voltage of the insulator in kV

Application and installation

Outdoor bushing insulators are suitable for use in high-voltage equipment. When conductors are routed from outdoor to indoor installations, they insulate the busbars at the point of passage.

Outdoor bushing insulators can be installed using the flange located in the middle section of the insulator body. The bushing insulator can be fastened to the partition wall with bolts passed through the two or four holes in the flange. Installation dimensions are shown on the outline drawings.

Selection

The appropriate bushing insulator type must be selected according to the rated voltage, the current to be carried and the magnitude of the breaking force acting on the bushing insulator.

Construction

The outdoor bushing insulator consists of a glazed porcelain insulator body, metal fittings at both ends for securing the conductor bar, and a flange located in the middle of the insulator body. The current is conducted by the installed copper rod or aluminium bar.

On the outdoor side, the conductor bar is welded to the cap, providing a watertight seal.

The metal fittings are secured to the insulator body with cement.

The metal fittings are protected against corrosion by a coating suitable for the climatic conditions.