Indoor post insulators of cast resin can be used for all indoor application, also in the tropics. They are suitable for temperatures -25�C to +90�C.
Construction
Indoor post isulators of aromatic cast resin are cylindrical solid insulator. The main dimensions are in accordance with IEC 60273 - 1990. Three fixing bushes are cast into the insulator top. The metal head fittings are electrically connected. One fixing bush is cast into the center of the insulators foot.
Tests
The following tests to IEC 60660 - 1999 are performed:
� Test with rated power-frequency withstand voltage (dry)
� Test with rated lightning impulse withstand voltage.
� Testing of minimum failing loads (nominal loads) for: bending, tension, torsion
Sample tests
� Testing of minimum failing load for: bending
Routine tests
� Visual inspection
� Test of conductive connection of threaded fixing bushes. For post insulators type B (IECC 60660 - 1999).
� Test with rated power-frequency withstand voltage (dry)
� Partial discharge extinction voltage test.
