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Project: T203700 #3727
 

The grounding of an electrical system is carried out mainly to limit the voltage imposed on its components in case of contact with higher voltage lines, protecting against lightning strikes and stabilizing the voltage during normal operation of the system. Recently, concrete encased reinforcing rebars have attracted electrical engineers’ attention as a promising grounding agent. This is because the concrete surrounding rebar has a lower electrical resistivity than the earth. Also, concrete is a porous material and has the tendency to absorb moisture from the surrounding earth. This turns concrete into a semi-conductive medium, providing an electrical pass to the earth. There are some issues and concerns related to the use of concrete encased electrodes in grounding, e.g., steel corrosion within concrete. This report provides an overarching review of the available standards, books, and research papers on the use of concrete encased steel rebars for grounding and related issues and concerns. A utility survey was also conducted to gain an understanding of the existing practices and techniques commonly employed by electric utilities for grounding of concrete foundations and walls. Lastly, a simple testing method is proposed that could be used by utilities to evaluate the resistivity of concrete in certain locations.

Keywords:

Concrete encased electrodes, reinforcement steel corrosion, concrete wall grounding, concrete foundation grounding, concrete resistivity measurement, Ufer ground.