October 12, 2023 | Susan Napier-Sewell

Overlooked Electrical Lock/Tag/Verify Step Contributes to Potential Exposure to Hazardous Energy


Workers must have the appropriate electrical and/or Lock/Tag/Verify (LTV) training and the work being performed must be authorized in the scope of their work control before performing electrical work on exposed electrical systems.

On September 4, 2020, a gas flow and pressure controller in a laboratory was having intermittent communication issues, ultimately leading to the electrical work on the exposed electrical systems. A research technician was trying to resolve the issues, with help from the manufacturer, without success. Another identical controller was located in an instrument/power cabinet in the lab. Based on the firmware version and date of manufacture, the controller could serve as a potential replacement so the technician decided to switch controllers to see if that would fix the problem.

The technician externally examined the cabinet rack with the replacement controller for electrical conduits, one of which was traced to a 480V power bus in an adjacent lab. The bus duct disconnect switch was actuated to the “off” position by the technician in accordance with the procedure for breaker operation rated up to 600V. While performing the disconnect, the technician wore a flame-resistant lab coat, hearing protection, safety glasses, and leather gloves.

Following the disconnect, the technician visually confirmed the instrument/power cabinet had no power and opened the back panel to facilitate the change out of the controller. The technician disconnected one 120V power cable and eight 15V DC control cables, removed the controller, and restored electrical power to the cabinet (commonly referred to as a bud rack) after the change out was complete. This action exposed the RT, who was not a qualified electrical worker, to deenergized unguarded 480V circuit parts. Per the Standards Based Management System (SBMS) requirements, to properly access the cabinet in this configuration, the RT would have been required to implement an LTV for the cabinet. Implementing an LTV for this cabinet requires completion of 1) LTV Training, and 2) Qualified Electrical Worker (QEW) Training. The RT did not have the appropriate training nor follow the appropriate SBMS LTV procedures.

A root cause analysis was performed on the electrical work event, and the root causes of this incident were determined to be:

  1. The research technician believed they understood the requirements for performing the task and did not consult work control documents such as the Research Safety Summary (RSS), nor did he consult with Laboratory Space Manager (LSM) or Principal Investigator (PI).
  2. The Electrical Worker Training completed by the research technician did not specifically address electrically safe deenergized conditions, although it did sufficiently address and warn of hazards associated with energized conditions. For most research staff members, working with energized electrical systems > 50 volts is not routine work. Before performing electrical work, research staff must engage their Division Electrical Safety Officer (DESO), the Principal Investigator, and the Lab Space Manager to discuss the scope of their electrical work required. The DESO can evaluate and assure that the staff member has the skill set to complete the job, has been assigned and successfully completed the appropriate electrical training, and is authorized to perform the electrical work under their work control (i.e., RSS). The research staff should remember to consult the RSS to determine if the scope of work has been authorized. Once the DESO has evaluated the applicable electrical training what electrical/LTV training is required, the research staff member should complete the training. It is important that staff understand the scope and limitation of their electrical training.

    Recommended Actions:
    • Review the work control associated with the scope of the electrical work that will be performed to ensure the electrical work is authorized.
    • Ensure research staff in the division know their DESO contact, or how to reach their DESO contact.
    • There must be important collaborative communication during job scoping to mitigate electrical hazards.
    • Ensure a qualified electrical worker who has completed lock/tag/verify training performs lock/tag/verify on the equipment prior to electrical work being performed. In addition, the authorized employee (who performs the service or maintenance work), must also hang their lock on the equipment before performing the work. The authorized employee must have completed lock/tag/verify training and other applicable electrical training before performing the electrical work. Collaborative communication between F&O qualified electricians, DESO, research staff and operations are critical to define and understand work scope and the task being performed. Everyone involved in the job should be aware of the hazards.

    SCOR (Safe Conduct of Research) Principles:
    • A questioning attitude is cultivated.
    • Hazards are identified and evaluated for every task, every time.
    • A healthy respect is maintained for what can go wrong.

Source: OPEXShare, Lesson Learned #37713, Oak Ridge National Laboratory, Sean Hearne, 2021-UTB-ORNL-0017, “Overlooked Electrical Lock/Tag/Verify Step Contributes to a Potential Exposure to Hazardous Energy,” DOE.

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