National Electrical Installation Standards

Standards as High as Your Own

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Monday, May 24, 2021

Question:

Greetings,

I am a building inspector currently doing inspections on new homes. The local building official requires a ufer connection to be installed per code. There seems to be some push back from electrical contractors that the current practice of putting plastic under a mono-slab footing negates the purpose of a ufer as a grounding source.  Code does say the concrete encasement must be in contact with the earth.  Reading up on some commentary about ufer utilization, it does point out that the concrete constantly wicks moisture from the earth to create an environment for efficient grounding. I would appreciate your comments on this situation.

James Sampson

A

Answer:

Hello James and thanks for the question.

The informational note following Section 250.52(A)(3) provides the needed guidance here. If there is a plastic or other insulator by a vapor barrier, etc. installed under a concrete foundation or footing and between the earth and the concrete, then there is no effective concrete incased electrode. The term "direct connection to the earth" is key as indicated in the definition of "grounding electrode" in Article 100 and as provided in the text of 250.52(A)(3). In this case as described in your question, and to comply with Section 250.50, other electrodes present, or those that may need to be installed, at the site, must be bonded together to form the grounding electrode system.

 
Hope this is useful.

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