In a letter of interpretation dated 12/16/1998, OSHA addressed the concerns of an employer regarding the use of electrical tape to repair minor damage (abrasions and cuts of limited depth) on the outer jacket of an extension cord. OSHA gives an in-depth answer to an age-old question for construction employers and employees.
Here is OSHA's response and the information you need when deciding to repair or replace that worn out or damaged extension cord:
You ask whether there is any prohibition against putting electrical tape over these kinds of abrasions and nicks when there is no damage beyond the jacket, the conductors have not been scraped or exposed, and the insulation inside the jacket has not been displaced or compressed. Generally, electrical tape may be used to cover superficial damage to cord jackets.
Section 1926.416(e)(1) [of the construction regulations] provides that "worn or frayed electrical cords or cables shall not be used." Superficial nicks or abrasions, those that only slightly penetrate the outer jacket of a flexible cord, and do not permit the cord to bend more in that area than in the rest of the cord, do not normally render a cord "worn or frayed." Therefore, there is no need to repair or replace such a cord.
Recommendation against taping
While taping these incidental abrasions and cuts does not necessarily violate any OSHA standard, we recommend that employers not tape this type of damage for two reasons. First, §1926.403(a) requires that "all electrical conductors and equipment shall be approved." This standard precludes the use of approved electrical conductors and equipment if their characteristics are significantly altered. Applying electrical tape that is too thick or applying too much of it could change the cord's original flexibility and lead to internal damage. Second, the depth of the abrasions and cuts cannot be monitored to see if they get worse without removing the tape.
It should also be kept in mind that the heavy duty extension cords commonly used on construction sites are designed to withstand a hostile environment. Damage to an extension cord that is bad enough to consider taping may have caused damage beyond the jacket.
Tape may not be used to repair significant damage to cord jackets
Repair or replacement of a flexible cord (depending on its gauge) is required when the outer jacket is deeply penetrated (enough to cause that part of the cord to bend more than the undamaged part) or penetrated completely, or when the conductors or their insulation inside are damaged.
Two provisions of the standard prohibit the repair of the jacket of a worn or frayed flexible cord with electrical tape. Section 1926.403(a) requires that the cord be approved. The original approval of the cord was based on the types of materials and construction used. As noted above, taping the cord can change the flexibility characteristics of the cord, which in turn can affect the amount of stress in the adjacent areas. This is of particular concern with respect to the grounding wire.
Also, the jacket is designed both to prevent damage to the conductors and insulators inside, and to further insulate the conductors. Taped repairs usually will not duplicate the cord's original characteristics. In most cases neither the jacket's strength nor flexibility characteristics will be restored. Therefore, tape repairs of the jacket may not be used to bring a worn or frayed flexible cord into compliance.
In addition, §1926.405(g)(2)(iii) states that "flexible cords shall be used only in continuous lengths without splice or tap. Hard service flexible cords No. 12 or larger may be repaired if spliced so that the splice retains the insulation, outer sheath properties, and usage characteristics of the cord being spliced." This standard precludes the repair of flexible cords smaller than No. 12.
