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 http://www.osha.gov.

May 27, 2003

Mr. Joe M. Castelli
Corporate Manager of Quality
Ajax TOCCO Magnethermic
1506 Industrial Boulevard
Boaz, AL 35957

Dear Mr. Castelli:

Thank you for your May 1 letter to the Occupational Safety and Health Administration (OSHA) regarding a multi-conductor "Litz" wire that may violate OSHA regulations. 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. Your paraphrased scenario, question, and our response are provided below:

Scenario: "A representative of a company who manufactures multi-conductor "Litz" wire informed us the brand of "Litz" wire we are currently using would probably violate some OSHA regulations. His statement was based on the fact the wire has a PVC insulating jacket and if caught fire would emit toxic fumes. The "Litz" wire is used in high frequency power supplies used for induction heat treating. We use sizes ranging from 4 to 8 AWG at frequencies between 1 and 50 KHz. Actual current through the conductors is typically around 60 Amps."

Question: Based on the information provided, the question is, are we in violation of some OSHA regulation?

Response: The OSHA standards covering electrical hazards associated with the electric equipment, including "Litz" wire described in your letter, are contained in 29 CFR, Subpart S, Sections 29 CFR 1910.302 through 1910.308. Pursuant to 29 CFR ยง1910.303(a), workplace electric conductors and equipment must be approved to be acceptable to OSHA. One way in which an electrical conductor or equipment is "acceptable" to OSHA and approved within the meaning of 29 CFR 1910 Subpart S is if it is accepted, or certified, or listed, or labeled, or otherwise determined to be safe by a nationally recognized testing laboratory (NRTL).

Furthermore, 29 CFR 1910.303(b)(2) requires that listed or labeled equipment shall be used or installed in accordance with any instructions included in the listing or labeling. The definitions for "listed" or "labeled" are stated in Section 29 CFR 1910.399 as follows:

  1. Equipment is "listed" if it is of a kind mentioned in a list that (a) is published by a nationally recognized laboratory, which makes periodic inspection of the production of such equipment, and (b) states such equipment meets nationally recognized standards or has been tested and found safe for use in a specified manner.



  2.  
  3. Equipment is "labeled" if there is attached to it a label, symbol, or other identifying mark of a NRTL (a) which makes periodic inspections of the production of such equipment, and (b) whose labeling indicates compliance with nationally recognized standards or tests to determine safe use in a specified manner.

A current list of NRTLs can be found at the OSHA's website address: http://www.osha.gov/dts/otpca/nrtl/index.html. You may contact them directly to get a list of equipment for which they have given approvals. One major NRTL, Underwriters Laboratories, Inc., can be contacted at:

Underwriter's Laboratories, Inc.
333 Pfingsten Road
Northbrook, IL 60062-2096
Phone (847) 272-8800
Website http://www.ul.com

Thank you for your interest in occupational safety and health. 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 http://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