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Effective, reliable grounding electrodes or grounding electrode systems are required for all electrical services and systems. This presented a problem for Herbert Ufer. During WWII, he served as an Army consultant overseeing the building of bomb storage vaults in the vicinity of Tucson and Flagstaff, Ariz. Ufer found the high-Ohm resistance of the dry, sandy Arizona desert presented a grounding challenge. Conventional ground rods were unable to meet the required low-ground resistance requirements. He addressed the challenge by developing a concrete-encased ground, which now carries his name, the Ufer ground.
Properties of concrete provide the key
The Ufer ground takes advantage of the properties of concrete. Essentially, concrete absorbs and retains moisture quickly, but loses it slowly over time. In addition, the composition and pH of concrete is such that it allows ionic transfer, which means that it has available ions to conduct electric currents. Furthermore, the soil around the concrete becomes “doped” by the presence of the concrete. As a result, the pH of the soil rises and consequently reduces what would normally be high-Ohm resistance conditions.
Ufer fond that a concrete-encased ground provides a safe, elegant and practical alternative to the exterior metal-driven rod system we all are familiar with and which we know can be subject to damage or tampering.Amendments to the 2008 NEC, National Electric Code have clarified some provisions of previous concrete encased electrode language. Although the word “Ufer” is not used in the text of the code, NEC Section 250.52(A)(3) addresses Ufer grounds.