Materials used
Overhead lines: equipment - Insulators

Up until the 1980s, only glass and ceramics had proven their worth in operation, even though both materials are inherently fragile.

• Ceramics. – They are currently used for high-voltage insulators and correspond to similar formulas, either Al₂O₃, SiO₂ (traditional porcelain), or Al₂O₃, 5 SiO₂ (soapstone).

  After the insulator has been machined from its cylindrical blank, either wet (cap-and-rod type) or dry (long-barrel type), it is fired in a furnace at a suitable temperature and for a suitable time.

  Some very fine-grained ceramics are recommended...