The shape of the earth electrode may vary from conductive rod, conductive plate, metal water pipe or any other conductor with low resistance. Earth electrodes are made of copper, galvanised iron, cast iron etc.
Hello Basim Talib Kadhem ,
I don't understand your question as you essentially answer it yourself. The material chosen will very much depend on the application and the guidelines / specifications for a given industry or country.
http://www.galvanizers.co.in/earthing-materials.html
https://www.nationalgrideso.com/document/33136/download
https://www.resourcesandgeoscience.nsw.gov.au/__data/assets/pdf_file/0016/101743/EES005-Electrical-Protection-and-Earthing-Guideline.pdf
Jules
Dear Dr. Basim Kadhem,
I suggest you to have a look of the following web sites where you can find very useful information:
- https://www.fluke.com/en-us/learn/blog/grounding/grounding-basics
- http://www.electrical-installation.org/enwiki/Installation_and_measurements_of_earth_electrodes
- http://www.reeve.com/Documents/Reeve_Ground%20Testing%20R1-1.pdf
Best regards, Pierluigi Traverso