February 19, 2008

Mr. John D. Weagraff
Manager, Corporate Safety
National Grid
300 Erie Boulevard W.
Syracuse, NY 13202

Dear Mr. Weagraff:

Thank you for your May 10, 2007 letter to the Occupational Safety and Health Administration's (OSHA's) Directorate of Enforcement Programs (DEP). This letter constitutes OSHA's interpretation only of the requirements discussed and may not be applicable to any scenario or questions not delineated within your original correspondence. You had specific questions regarding the Electric power generation, transmission and distribution standard, 29 CFR §1910.269. Your scenario, paraphrased questions, and our replies follow:

Scenario: In-house line-clearance tree-trimming operations currently use insulated fiberglass trimming poles that are clearly labeled Do Not Use as a Hot Stick. During annual testing procedures, many of the tools failed the wet test. Further lab testing proved the tool would pass the dry test, but not the conditioned test portion of the requirements in ASTM F711-02. However, in a clean and dry state, the tool did pass.

Question 1: Pursuant to 1910.269(r)(1)(iv), do line-clearance tree-trimming tools, used as insulating equipment, have to meet or exceed both the wet and dry tests as outlined in ASTM F711-89 or F711-02?

Reply 1: No, although employers routinely do comply with 1910.269(r)(1)(iv) by using tools that satisfy both ASTM tests.

Under 1910.269(r)(1)(iv), "[b]ranches that are contacting exposed energized conductors or equipment or that are within . . . [specified minimum approach] distances ... may be removed only through the use of insulating equipment."¹ To be "insulated" in accordance with 1910.269(r)(1)(iv), a tool must be insulated for "the conditions to which it is normally subjected." [29 CFR 1910.269(x)]. This means that the tool must be able to withstand the relevant voltage in both low-humidity and high-humidity conditions. The test methods in ASTM F711, although not specifically required by 1910.269(r)(1)(iv), expose the tool to test conditions that simulate dry (low-humidity) conditions and high-humidity conditions. The latter, commonly referred to as a "wet test," is intended to determine the tool's ability to withstand the test voltage when the tool has been exposed to high levels of humidity. (Although often referred to as a "wet test," the high-humidity test does not indicate the tool's insulating capabilities when wet. In fact, Section 12.2.4.2(c) of ASTM F711-02 requires the rod or tube to be wiped with a dry cloth before undergoing the test, i.e., the rod or tube is dry when tested.)²

Tests other than those in the ASTM standard could be adequate to satisfy the (r)(1)(iv) requirement as long as they demonstrate that the line-clearance tree-trimming tools in question are capable of withstanding the relevant voltages under high-humidity and low-humidity conditions. Note that under paragraph 1910.269(r)(1)(iv), individual poles need not be tested as long as there is evidence "indicating that tools of a given construction generically meet the test criteria." [59 FR at 4411].

Question 2: If the insulating equipment only meets the test requirements of ASTM F711, Sections 12.2.5A and 12.2.5.1B, does it comply with 1910.269(r)(1)(iv)?

Reply 2: No. The test methods given in ASTM Section 12.2.5 are for routine testing of fiberglass-reinforced plastic rods and tubes and would not ensure that the tools are insulated for the conditions to which they are normally subjected. These tests are appropriate only for tools that are, first, capable of passing the electrical design tests in ASTM Section 12.2.4, described above.

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 may consult OSHA's website at http://www.osha.gov. If you have any further questions, please feel free to contact the OSHA Office of General Industry Enforcement at (202) 693-1850.


Sincerely,



Richard E. Fairfax, Director
Directorate of Enforcement Programs

 

¹   A note following 1910.269(r)(1)(iv) explains that "[a] tool constructed of a material that the employer can demonstrate has insulating qualities meeting paragraph (j)(1) of . . . [1910.269] is considered as insulated . . . if the tool is clean and dry. "Please note that the tool must be clean and dry at the time of use, not at the time of the test. Therefore, tools that are clean, dry, and meet the insulating requirements of 1910.269(j)(1) are considered insulated under (r)(1)(iv).

Paragraph 1910.269(j)(1) states that live-line tool rods, tubes, and poles made of fiberglass-reinforced plastic must be designed and constructed to withstand 100,000 volts per foot of length for 5 minutes, although 1910.269(j)(1)(iii) states that other equivalent tests are acceptable. Moreover, a note following paragraph (j)(1) clarifies that OSHA considers live-line tools using rod and tube to be in compliance if they satisfy ASTM F711-89.  [ back to text ]

²  The importance of the high-humidity test is discussed in the preamble to 1910.269. 59 FR 4320, 4378 (Jan. 31, 1994). [ back to text ]