Grounding a fan on a concrete floor

November 26, 2003

Mr. Thomas M. Krena

Corporate Risk Prevention Manager

[Recipient address omitted]

Dear Mr. Krena:

Thank you for your July 25 letter to the Occupational Safety and Health Administration (OSHA), regarding the OSHA rule at 29 CFR 1910.304(f)(5)(v)(C)(5). This letter constitutes OSHA's interpretation only of the requirements discussed, and may not be applicable to any questions not delineated within your original correspondence. We apologize for the delay in our response. Your scenario, questions, and our responses are provided below:

Scenario: The OSHA rule at 29 CFR 1910.304(f)(5)(v)(C)(5) indicates that exposed non-current-carrying metal parts of cord-and plug-connected equipment used in damp or wet locations or by employees standing on the ground or on metal floors or working inside metal tanks or boilers which may become energized must be grounded.

Question 1: What is the definition of "ground" in the above statement? Is it referring to exposed soil or to a dry concrete floor on grade or to a dry concrete floor above grade or all the above?

Reply: The term "ground" referred to in 29 CFR 1910.304(f)(5)(v)(C)(5) is defined in 29 CFR 1910.399 as: "A conducting connection, whether intentional or accidental, between an electrical circuit or equipment and the earth, or to some conducting body that serves in place of the earth." Thus a dry concrete floor on grade or above grade would be an example of ground, if the floor is a conducting body. Concrete floors are likely to be grounded. We would note in this regard that another provision of the electrical standards, 29 CFR 1910.303(g)(1)(i), requires that concrete, brick and tile walls be considered to be grounded.

Question 2: Would you consider an ungrounded fan, on a dry concrete floor, on grade, in an industrial setting a violation of this specific standard?

Reply: The use of an ungrounded fan situated on a dry concrete floor on grade in an industrial setting will be a violation of the OSHA rule at 1910.304(f)(5)(v)(C)(5), if the fan has exposed non-current-carrying metal parts that can be contacted by employees. Concrete on grade level, because it will absorb moisture from the earth and be a good conductor in direct contact with the earth, is always considered to be at ground potential.

Thank you for your interest in occupational safety and health. OSHA requirements are set by statute, standards, and regulations. Our interpretation letters explain these requirements and how they apply to particular circumstances, but they cannot create additional employer obligations. Note that our enforcement guidance may be affected by changes to OSHA rules. Also, from time to time we update our guidance in response to new information. To keep apprised of such developments, you can consult OSHA's website at http://www.osha.gov. If you have any further questions, please feel free to contact the Office of Health Enforcement at (202) 693-2190.

Sincerely,

Richard E. Fairfax, Director

Directorate of Enforcement Programs