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.

February 10, 1977



Subject: Ground Fault Protection

Attached are the answers to your memorandum of January 4, 1977. These answers have been prepared by the Electrical Division of the Office of Standards Development. Since they have prepared all the data on GFCI's, it was decided to have that Division formulate the reply. This insures a uniform answer to all inquiries.

The Electrical Division's reply to question No. 2 requires further clarification. An employer plugging into an unprotected outlet with his portable GFCI would be in violation of 29 CFR 1926.401(h), which requires all temporary wiring to be effectively grounded.

Richard P. Wilson
Deputy Director,
Federal Compliance and State Programs