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Ground-fault protection on permanent construction wiring

Summary An OSHA memorandum addressed a portable tool plugged through an extension cord into a permanent 120-volt construction-site receptacle. It said a GFCI could be used but was not required in that scenario. Without a GFCI, the employer needed the specified assured equipment grounding conductor program.
Document
Federal opinion letter
Agency
Occupational Safety and Health Administration (OSHA)
Document number
1979-01-12
Date issued
January 12, 1979
Status
Active
Status last verified October 10, 2026

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About this page: The full text below is the official document from Occupational Safety and Health Administration (OSHA). Ezel adds the plain-English summary and tracks the document's status. The official source linked on this page is authoritative for any reliance.

January 12, 1979

MEMORANDUM FOR: CURTIS A. FOSTER
REGIONAL ADMINISTRATOR - DENVER

THRU: DONALD E. MACKENZIE Field Coordinator

FROM: IRVING WEISBLATT, Acting Director,
Directorate of Federal Compliance and State Programs

SUBJECT: Clarification of 1910.309(c)(2) and 1926.400(1)(2):
Ground Fault Protection

In the specific instance on a construction site, where the permanent wiring is in place and in use, and an employee plugs an extension cord into a permanent 120 volt, single-phase receptacle outlet, and then plugs a portable electric tool into the extension cord, a GFCI may be used but is not required. However, if the GFCI is not used under these conditions then and assured equipment grounding conductor program is required covering all cord sets, receptacles which are not a part of the permanent wiring of the building or structure, and equipment connected by cord and plug.

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