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NOTICE: This is an OSHA Archive Document, and may no longer represent OSHA Policy. It is presented here as historical content, for research and review purposes only.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

DATE:                  June 12, 1991

                       DISTRICT SUPERVISORS

FROM:                  LINDA R. ANKU
                       REGIONAL ADMINISTRATOR

SUBJECT:               Extension Cords Acceptable for Use

Only extension cords (cord sets) that are approved, as an assembly, by a Nationally Recognized Testing Laboratory (NRTL) such as UL are permitted to be used at places of employment. This limitation is based on the requirement that all equipment be approved as set forth in 29 CFR 1910.303(a) and 29 CFR 1926.403(a).

There are a large number or extension cords purchased and used by employers that are not approved for use by a NRTL. This is particularly a problem on construction sites. There are extension cords used on these sites that are referred to by the manufacturer as contractor or handyman cords but they are not approved.

Currently UL approves most extension cords. When UL approves equipment it is marked with the UL label and on that label will be the name of the equipment or the assembly that is approved. This is an important point because the presence of a UL label on a piece of equipment does not necessarily mean that the entire assembly the equipment is part of is approved. In many cases the UL label only means that one component of the assembly is approved; not that the entire assembly is approved. The cord, attachment cap (plug), or receptacle portion of the extension cord could be approved but the entire assembly that is the extension cord would not have a UL approval unless it was so marked. Therefore, such a cord would not be acceptable.

The danger associated with the use of extension cords that are not approved is that such cords may not be constructed properly or they may not be appropriate for the environment in which they are being used. A listing or approval of equipment by a NRTL substantially reduces the possibility of such problems.

Employers supplying unapproved cords for their employees use should be cited. A reasonably predictable injury for this type of a violation would be electrical shock.

If you have any questions regarding this matter, please contact John McFee at FTS 596-1201.