Permanently labeled locks for electrical lockout

August 17, 2026

Shane Child
[Recipient address omitted]

Dear Shane Child:

Thank you for your letter to the Occupational Safety and Health Administration (OSHA), requesting clarification regarding the requirements of OSHA’s selection and use of work practices standard for electrical work and specifically 29 CFR §1910.333(b)(2)(iii). This constitutes OSHA’s interpretation only of the requirements discussed herein and may not be applicable to any questions not delineated within your original correspondence. Your paraphrased background information, question, and response to your question, are below.

Background: 29 CFR §1910.333(b)(2)(iii)(A) states, in relevant part, "A lock and a tag shall be placed on each disconnecting means used to deenergize circuits and equipment on which work is to be performed….” §1910.333(b)(2)(iii)(B) requires that each tag used in a lockout/tagout procedure must “contain a statement prohibiting unauthorized operation of the disconnecting means and removal of the tag."

Question 1: Would a lock bearing a permanently affixed label stating "unauthorized operation of the disconnecting means and unauthorized removal of the lock are prohibited" satisfy the requirements of §1910.333(b)(2)(iii)(A) and (B)?

Response: Yes. The purpose of §1910.333(b)(2)(iii)(B) is to ensure that equipment remains de-energized, preventing accidental re-energization while workers are performing maintenance. §1910.333 does not specify a particular format for the tag, which is consistent with the related control of hazardous energy (lockout/tagout) standard, 29 C.F.R. §1910.147. That standard defines a tagout device as “A prominent warning device, such as a tag and a means of attachment, which can be securely fastened to an energy isolating device in accordance with an established procedure, to indicate that the energy isolating device and the equipment being controlled may not be operated until the tagout device is removed,” indicating that tags need to meet certain requirements but do not need to take any particular form. A lock with a permanently affixed, legible label, stating that "unauthorized operation of the disconnecting means and unauthorized removal of the lock are prohibited," would meet the requirements of the standard at §1910.333(b)(2)(iii)(A) and (B).

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 http://www.osha.gov. If you have any further questions, please feel free to contact the Directorate of Enforcement Programs at (202) 693-2100.

Sincerely,

Erin P. Gilmore, Acting Director
Directorate of Enforcement Programs