Archive Notice - OSHA Archive

NOTICE: This is an OSHA Archive Document, and may no longer represent OSHA Policy. It is presented here as historical content, for research and review purposes only.

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

October 28, 1985


Regional Administrator
FROM: JOHN B. MILES, JR., Director
Directorate of Field Operations
SUBJECT: Applicability of (29 CFR 1926.400(h))
Ground-fault Protection Standards When
Extension Cords are Plugged into Permanent
Wiring at Construction Sites
REFERENCE: Your November 25, 1984, Memorandum Requesting a
Clarification of 29 CFR 1926.400(h)


In the past we have made the interpretation under 29 CFR 1926.400(h)(2) that receptacle outlets which are part of the permanent wiring are not required to have GFCI. This did not meant that the employer could avoid the requirements simply by powering tools by means of extension cords from permanent receptacle outlets. Generally, extension cords are equipment used as temporary wiring (i.e., as a substitute for the fixed wiring of a building or structure) to provide power to areas remote from the permanent receptacle outlets. Therefore, we determined that the receptacles (or cord connectors) at the ends of such extension cords were receptacle outlets which are not a part of the permanent wiring of the building or structure and that a GFCI is required to protect employees.

A recent OSHRC decision will not support the aforementioned enforcement policy without substantiation that the hazards contemplated by the standard exist at the work location, thereby exposing employees to electric shock by providing a path to ground for current. These hazards would be present when employees are using electric tools in locations which provide a ready grounding path for current, such as damp or wet locations, outdoor areas, locations where building steel is present, areas where concrete slabs in contact with the earth are present, and other similar areas.