Grounding systems 
For building electrical grounding systems or earthing systems there is a low resistance conductor bonding the metalwork and this is connected to a groundbed. The electrodes for electrical grounding are often called ground rods and are often made from steel with a copper clad surface – typically 1 to 2m long and 20 millimetres (0.79 in) in diameter. These are driven vertically into the ground and bonded together with bare copper wire.
Cathodic protection 
- Electrical Engineer's Reference Book, Sixteenth edition by M. A. Laughton CEng., FIEE and D. J. Warne CEng., FIEE, Newnes, 2003, ISBN 0 7506 46373
- NACE/ASTM G193 – 10a Standard Terminology and Acronyms Relating to Corrosion 2010