We Wrote The Book on Grounding and Earthing

Toll Free: 888.367.0888

Ask The Experts Blog

Can a 20 foot deep, 12 inch diameter hole filled with concrete (and 1/2” rebar in the middle) installed vertically into the earth be used as a concrete encased electrode?

David Tells us:

I have a facility with very little real estate available that needs grounding electrode conductors. None where installed during the original construction of the facility (though somehow it passed inspection) in the early 1980s. The soil has very high resistivity, and is very rocky. There is not room for traditional driven ground rods, nor will they be effective given soil conditions. I am looking to take the concrete encased electrode concept and turn it vetically (rather than horizontally as Mr. Ufer did) into the earth.

 

Hi David,

Thank you for your question regarding concrete encased electrodes.  It is our pleasure to help.

E&S Grounding Solutions does not recommend any grounding electrode systems that utilize concrete.  The water that is inherent in the concrete can turn to steam under high-current faults such as lighting strikes and/or utility line-to-ground faults.  When this happens, the steam will crack the concrete destroying the electrode.  As the electrode is buried it can be very difficult to detect this problem, resulting in life-threatening situations.  Also, many concrete systems utilize carbon-based materials such as coke-breeze that will corrode the copper components as they have differences in metallurgic nobility.

We would recommend that you consider an electrolytic grounding electrode for your situation.  It sounds as if depth is your only solution.  If the resistance of your soil gets worse with depth, you may find that drilling deeper will have little benefit for you, but as you have little choice, that may be the best you can do.  You should check with your driller and see what depth they can go to for the price.  Often, the driller will drill a 40-ft hole for the same cost as a 20-ft.  Unless you are willing to conduct an actual engineering analysis and design, which we can do for you.

If you have any further questions, please do not hesitate to contact us at 310-318-7151 and someone will be glad to speak with you about your project, free of charge.

Best regards,

The Engineering Team at E&S Grounding Solutions

 

Photo credit: E&S Grounding Solutions

Leave a Reply