Editing Porcelain (section)

=== Electric insulators ===
[[File:Insulators for 66kV Power Line (Ibaraki,Japan) 02.jpg|thumb|A string of 8 insulators on a 66 kV transmission line]]
Porcelain has been used for electrical insulators since at least 1878,<ref>'Insulators For High Voltages.' J. S. T. Looms. Institution of Electrical Engineers. 1988. Pg. 4</ref> with another source reporting earlier use of porcelain insulators on the telegraph line between Frankfurt and Berlin.<ref>'High-Voltage Insulators: Basics and Trends for Producers, Users and Students.' J. Liebermann. Schulze. 2012. Pg. 15</ref> It is widely used for insulators in electrical power transmission system due to its high stability of electrical, mechanical and thermal properties even in harsh environments.<ref>'Development Of Electrical Porcelain Insulators From Local Clays' C.C. Okolo; O.A. Ezechukwu; E.N. Ifeagwu E. N & R.C. Unegbu. International Journal of Engineering Innovation & Research. Volume 3, Issue 6, ISSN: 2277 – 566</ref>

A body for electrical porcelain typically contains varying proportions of ball clay, kaolin, feldspar, quartz, calcined alumina and calcined bauxite. A variety of secondary materials can also be used, such as binders which burn off during firing.<ref>'Manufacture of Porcelain Insulators' INMR magazine June 2022</ref> UK manufacturers typically fired the porcelain to a maximum of 1200&nbsp;°C in an oxidising atmosphere,<ref>'Insulators For High Voltages.' J. S. T. Looms. Institution of Electrical Engineers. 1988. Pg. 60</ref> whereas reduction firing is standard practice at Chinese manufacturers.<ref>'The Influence of Kiln Atmospheres on Electrical Porcelain Firing' Hong Yin, Xhengqun Liu, Xiaoli Hu. Ceram. Eng. Sci. Proc. 15. [1] 176-179. (1994)</ref>

In 2018, a porcelain [[Bushing (electrical)|bushing]] insulator manufactured by [[NGK]] in [[Handa, Aichi|Handa]], [[Aichi Prefecture]], [[Japan]] was certified as the world's largest ceramic structure by [[Guinness World Records]]. It is 11.3 m in height and 1.5 m in diameter.<ref>{{cite web | url=https://www.guinnessworldrecords.com/world-records/521076-largest-ceramic-structure#:~:text=NGK%20INSULATORS%2C%20LTD.&text=The%20largest%20ceramic%20structure%20is,achieved%20by%20NGK%20INSULATORS%2C%20LTD | title=Largest ceramic structure | date=25 September 2018 }}</ref><ref>{{cite web | url=https://www.ngk-insulators.com/en/news/20190913_10590.html | title=Transformer Insulators Recognized by Guinness World Records &#124; News }}</ref>

The global market for high-voltage insulators was estimated to be worth US$4.95 billion in 2015, of which porcelain accounts for just over 48%.<ref>'Overview of World Markets for Insulators & Bushings' INMR magazine Sept. 2016.</ref>