Standard Interpretations - Table of Contents|
| Standard Number:||1910.269(m) ; 1910.269(n)(2) ; 1910.269(n)(6) ; 1910.269(n)(7)|
December 6, 1999
Mr. John D. Weagraff
Manager OSHA Regulatory
Compliance / Accident Prevention
300 Erie Boulevard West
Syracuse, NY 13202-4250
Dear Mr. Weagraff:
Thank you for your August 9, 1999 letter to the Occupational Safety and Health Administration's (OSHA's) Directorate of Compliance Programs. You have questions regarding the application of personal protective grounds, for the protection of employees, as required in the Electrical Power Generation, Transmission, and Distribution Standard, 29 CFR §1910.269. Your background information, questions, and our responses follow:
Background: Niagara Mohawk has 5kV porcelain enclosed disconnect switches on riser poles, installed throughout its service territory. These are connected to and used to isolate underground cables as per paragraph (m). Internal operating procedures require either the line or load side leads to the disconnect be removed in order for the open disconnect to be an acceptable energy isolating point. This is accomplished using rubber-gloving methods.
When this lead is removed, applying grounds with a live line tool is nearly impossible due to the instability of the lead. The small size of the high seal end, the weight of the ground, and the ground wire conductor, typically #2 or #4/0 copper, make this impractical. Paragraphs (n)(6) and (n)(7) are clear regarding the application of grounds using a tested live line tool, however (n)(2) offers grounding alternatives.
Question #1: Is it acceptable to apply personal protective grounds without a live line tool by hand using rubber glove methods while protecting line personnel with class II rubber gloves and sleeves, flame retardant upper body clothing, UV protective safety glasses with side shields and a face shield without using a live line tool?
Response: No. The preamble summary and explanation section to this rule (Federal Register 59(20), Monday, January 31, 1994, p. 4396), for §1910.269(n)(6) and (n)(7), contains the following justification:
Several commenters were concerned that this language implied that rubber gloves could be used to install and remove grounds. They noted that it is unsafe for an employee to be too close, when connecting or disconnecting a ground, and urged OSHA to eliminate the phrase "or other insulated devices" from the rule. The Agency agrees with these commenters, and has adopted their suggestion in the final rule. OSHA will consider any device that is insulated for the voltage and allows an employee to apply or remove the ground from a safe position, to be a live line tool for the purposes of 1910.269(n)(6) and (n)(7).
This explanation makes it clear that an insulating tool is necessary to maintain an employee at a safe distance when installing or removing grounds. The use of electrical protective equipment alone may expose employees to serious unexpected conductor energization hazards from the associated electric arcing and severe heat. Rubber insulating gloves would not adequately protect employees against these hazards, whereas a live line tool will maintain employee exposures at a safe distance.
Please note that the preamble also clarifies that a traditional live-line tool, or hot stick, is not the only acceptable tool that an employee can use to perform this task. OSHA is aware of some utilities that are using specially designed tools that will provide the needed insulation and distance for the employee to apply the type of small sized grounds to which your letter refers.
Question #2: Considering the background information described above, does 1910.269(n)(2) allow the application of protective grounds without a live line tool after all three of the requirements (n)(2)(i-iii) are met? The grounds are placed to add additional employee protection.
Response: No. As noted in §1910.269(m), lines and equipment must be treated as energized until they are deenergized, tested, and grounded. Grounding may only be omitted, as permitted by paragraph (n)(2), when the installation of a ground is impractical or if the conditions would introduce a more serious hazard than working without grounds. The exception applies to the ability to install a ground and not to the ability to use a particular grounding method.
Question #3: In order to treat the lines as de-energized, and work without grounds, three conditions must be met (n)(2)(i), (ii), (iii). Under (n)(2)(i), it requires the provisions of paragraph (m) be followed. Please clarify if the requirement of (m)(3)(vi) relates to the requirement set forth in (n)(2)(i).
Response: Before lines or equipment are treated as deenergized, paragraph (m)(3)(vi) requires the lines or equipment to be deenergized, tested, and "grounded in accordance with paragraph (n)."1 If paragraph (n) requires a line or equipment to be grounded, as in the case described in your letter, then it must be grounded before it can be considered deenergized. If paragraph (n) does not require a ground to be installed, then the line or equipment may be considered as deenergized after it is tested and the deenergized state is verified.
Thank you for your interest in occupational safety and health. We hope that you find this information helpful. Please be aware that OSHA's enforcement guidance is subject to periodic review and clarification, amplification or correction. Such guidance could also be affected by subsequent rule making. In the future, should you wish to verify that the guidance provided herein remains current, you may wish to 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 Compliance Assistance at (202) 693-1850.
Richard E. Fairfax, Director
Directorate of Compliance Programs
Footnote (1) For example, customer-owned generators may pose the hazard of electrical backfeed, and the hazard of capacitive voltage build-up on underground cables should always be considered. This residual energy must be deenergized in accordance with paragraph (m)(3), including the isolation of and bleeding off of the cable voltage in accordance with (m)(3)(ii). [Back to text]
|Standard Interpretations - Table of Contents|
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