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. This letter constitutes OSHA's interpretation of the requirements discussed. 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 https://www.osha.gov.


May 12, 1997

[Name Withheld]

Dear [Name Withheld]:

Thank you for your letter dated April 11, addressed to the Directorate of Safety Standards, requesting an interpretation of the Occupational Safety and Health Administration (OSHA) Permit-Required Confined Spaces (PRCS) standard, 29 CFR 1910.146. Your letter was referred to this office for response.

With regard to your question whether the introduction of electrical welding equipment into a non-permit confined space automatically leads to a reclassification of the space to a PRCS, please be advised that as long as the protective measures of Subpart Q — Welding, Cutting and Brazing, prevent a hazard from developing, the use of electrical welding equipment would not cause a confined space to be classified as PRCS.

The protective measures of other standards would be applicable to the work in this space, specifically the following paragraphs of Subpart Q. [1910.252(a)(4)(i), 1910.252(b)(4)(i) to 1910.252(b)(4)(vii), 1910.252(c)(4), 1910.252(c)(9), and 1910.252(c)(10)] must be followed.

In addition, please be advised that the use of cord and plug electrical equipment in a non-permit confined space does not cause the non-permit space to become a PRCS.

We appreciate your interest in occupational safety and health. If we can be of further assistance, please call [(202) 693-1850].


John B. Miles, Jr., Director
Directorate of Compliance Programs

[Corrected 4/14/2009]