Iowa Electrical Examining Board

Concrete-Encased Electrode

Due to the increased use of nonmetallic water piping and isolation fittings, underground water piping systems have become less reliable as a grounding electrode. The increased sensitivity of our electrical systems in our homes, offices, and factories require the most dependable grounding system available. As a consultant to the US Army in the 1940's, Mr. Ufer determined that steel re-bar in the building footing provided the best grounding system available, even in dry soil conditions. The principle of this system is simple, effective, and inexpensive to install during new construction. Today, this system is still commonly called the Ufer Ground but is technically a concrete-encased electrode (CEE). In Article 250, the National Electrical Code has recognized and encouraged this electrode for years. In the 2005 issue of the NEC, attachment to the footing re-bar became a mandated requirement of the building grounding electrode system.

Below is an illustration of what many jurisdictions have found, with successful results, to be the simplest procedure to install this electrode. The concrete contractor stubs up a #4 rebar at a few inches above finished floor height. This stub shall be connected by at least two tie wires to no less than twenty (20) feet of tied, uncoated rebar in the footing. Locating this stub-up in the vicinity of the electrical service will minimize the length and cost of the grounding electrode conductor that connects to the electrical service equipment. You should confer with your general contractor or electrical contractor as to the preferred location.

If you have any questions, you should contact the electrical contractor doing the electrical work. If they are not available, you can contact the State Electrical Inspector assigned to the project area

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