Toolbox Talk: Section Insulator Splice Failure – Learning from Incident at Substation 5:

    Toolbox Talk: Section Insulator Splice Failure – Learning from Incident at Substation 5:

    Date of Incident: 07/04/2025

    Time: 03:10

    Location: Structure W8011, Wolverhampton Line

    Incident Type: Section Insulator Splice Failure & Overhead Line De-wire

    WHAT HAPPENED?

    During the installation of an Arthur Flury (FG3) twin contact Section Insulator (S.I.), a serious failure occurred:

  • After completing the splicing process and cutting the contact wire, the twin contact wire detached from the splices on the Wolverhampton side.
  • This caused a de-wire of Wire Run 12, posing a significant risk to both equipment and personnel.

    • IMMEDIATE CAUSES IDENTIFIED:

    Initial investigation highlighted several key issues:

  • Incorrect positioning of the contact wire in the grooves of the splice.
  • Premature tightening of lock nuts before securing the bolts.
  • No safety rigs were installed before cutting the contact wire.
  • Possible defective splices on the section insulator.

      • WHY THIS MATTERS:

      This failure could have caused serious injury or a major operational disruption. Understanding and addressing the root causes is crucial for:

    • Preventing future incidents.
    • Maintaining the integrity of our overhead line systems.
    • Protecting everyone working on or near the infrastructure.

      • KEY SAFETY LEARNINGS AND ACTIONS

      1. Follow Installation Sequence Exactly

    • Ensure the contact wire is correctly seated in splice grooves.
    • Bolts must be torqued first to 50 Nm, followed by lock nuts to the same torque.


    2. Always Use Safety Rigs

  • Safety rigs must be installed on both sides of the section insulator before cutting any wires.


    3. Mandatory Checks by Supervisors

    A Field Engineer, Construction Manager, or Supervisor must inspect:

  • The wire seating in splices
  • Torque settings on bolts and lock nuts
  • General condition of splices

    • 4. Re-brief All Staff

  • A safety stand down has been completed. Ensure all team members are familiar with the correct installation process for Arthur Flury FG3 S.I.s.

    • WHAT YOU CAN DO

  • Speak up if anything seems out of order or rushed.
  • Double-check splice installations and torque settings.
  • Never cut contact wire until safety rigs are in place and checks are signed off.
  • Report damaged or questionable components immediately.

    • DISCUSSION POINTS

  • Have you experienced any issues with section insulator installations?
  • Do you know the correct torque values and procedure for installing these splices?
  • Are safety rigs always being used on your team before cutting contact wires?

    • FINAL REMINDER

    This incident was preventable. By sticking to safe systems of work, following procedure, and not rushing under pressure, we all go home safely.

    STAY ALERT. STAY SAFE. SPEAK UP.

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