Article 250

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Grounding and Bonding 250.50 Grounding Electrode System Part III. Grounding Electrode System and Grounding Electrode Conductor The words “if available” have been replaced with “are present.” The effect is that a concrete-encased electrode (Ufer) is always required for new construction, because it is present. However, a new exception adds clarity that a concrete-encased electrode [250.52(A)(3)] isn’t required for existing buildings or structures. All grounding electrodes as described in 250.52(A)(1) through (A)(6) that are present at each building or structure must be bonded together to form the grounding electrode system. Figure 250-15 Ex: Concrete-encased electrodes are not required for existing buildings or structures where the conductive steel reinforcing bars aren’t accessible without disturbing the concrete.

Figure 250-15 (Click on image to enlarge)