Standard Interpretations - Table of Contents Standard Interpretations - Table of Contents
• Standard Number: 1910.305; 1910.305(a)(2)(iii)(G) ; 1910.305(g)(1)(iii)

May 5, 2006

Mr. Robert E. Jones
Senior Nuclear Analyst, Maintenance Technical
Seabrook Station
FPL Energy, LLC.
P.O. Box 300
Seabrook, NH 03874

Dear Mr. Jones:

Thank you for your September 8, 2005, letter requesting clarification of the Occupational Safety and Health Administration (OSHA) standard, 29 CFR 1910.305(g), pertaining to flexible cords and cables. This letter constitutes OSHA's interpretation only of the requirements discussed, and may not be applicable to any questions not delineated within your original correspondence. We apologize for the delay in our response. Your paraphrased scenario, question, and our response are provided below.

Scenario: Seabrook Station is a power generating facility. To support the operation of the plant either on-line or when it is shutdown for maintenance, it is necessary to install temporary power. The temporary power is installed by qualified electricians, and the installations are governed by site administrative procedures. In most cases, the temporary installation is used to supplement the permanent wiring, because the temporary loads will exceed the rating of the installed wiring system. Example applications, for which temporary power is used, are listed below.
  • Lighting when primary power equipment is down for maintenance
  • Supplemental power to offices, cafeteria, shops, and as such, when the primary power sources are down for maintenance
  • Supplemental power to shops and office buildings for monitoring and to robotic equipment (i.e., computers and closed circuit television)
  • Supplemental power to machinery acquired specifically for the plant outage
  • Supplemental power for temporary wiring

The temporary installations discussed above, employ flexible wiring and cables, including, in some cases, extension cords. There are applications in which the flexible cables are run through windows, doors and above ceiling tiles. In such cases, the electrician takes measures to protect cables from accidental damage.

In accordance with 1910.305(a)(2), the wiring methods may be of a class less than would be required for a permanent installation. In addition, the regulation states that all other requirements of the subpart for permanent wiring shall apply for temporary wiring installations.

Question: Does 1910.305(g)(1)(iii) suggest that flexible wiring and cables cannot be run through walls, ceilings, floors, doorways, windows, or similar openings when used in temporary service applications? Or, does this section only prohibit the practice when used as a substitute wiring method in permanent applications?

Response: In accordance with 1910.305(g)(1)(iii), flexible cords may not be used in permanent installations as specified in (A) through (E) below:
(A) As a substitute for the fixed wiring of a structure;
(B) Where run through holes in walls, ceilings, or floors;
(C) Where run through doorways, windows, or similar openings;
(D) Where attached to building surfaces; or
(E) Where concealed behind building walls, ceilings, or floors.
When these cords (including extension cords) are used in temporary wiring installations, 1910.305(a)(2)(iii)(G), allows them to run through doorways or other pinch points, such as windows or other similar openings, provided they are protected from damage. This provision does not, however, except them from the other four prohibitions, (A), (B), (D), and (E) above.

In other words, flexible cords when used in temporary wiring may be run through doorways, windows, or similar openings provided they are protected from damage, but cannot be used as a substitute for the fixed wiring of a structure; run through holes in walls, ceilings, or floors; attached to building surfaces; or concealed behind building walls, ceilings, or floors.

Thank you for your interest in occupational safety and health. We hope you find this information helpful. 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 www.osha.gov. If you have any further questions, please feel free to contact the Office of General Industry Enforcement at 202-693-1850.

Sincerely,



Richard E. Fairfax, Director
Directorate of Enforcement Programs
Standard Interpretations - Table of Contents Standard Interpretations - Table of Contents