Safety Reminders After Three Minor Shock Events in Last Month

Safety Reminders After Three Minor Shock Events in Last Month


There have been three minor electrical shock events at Jefferson Lab over the last month.  Fortunately, no one was injured.  In each case, work was stopped and proper mitigations were put in place, supervisors were notified, workers reported to Occupational Medicine for evaluation, and investigations into the events and potential extent of conditions were initiated.

The three events are summarized here for your information:

  • A worker in the Low Energy Recirculator Facility (LERF) was in the process of removing a DC output conductor from a power supply cabinet.  Lock, Tag, & Try was applied per the equipment procedure.  The worker received an electrical shock when their elbow brushed against the grounded cabinet frame.
  • A worker in Hall B was using a heat gun while applying heat-shrink tubing.  The heat gun was plugged into a permanent outlet near the wire racks in Hall B.  The worker inadvertently touched the metallic end of the heat gun while it was powered on and experienced a shock up to his elbow that was in contact with the grounded equipment rack.
  • A worker in Hall A was using a portable bandsaw that was plugged into an electrical outlet on a JLG-manlift when he felt a slight shock in his forearm.

Although not considered contributing causes to these events, here are some electrical safety reminders to keep in mind while preparing for and conducting work:

  • Check tools and cords before use; look for possible frayed or taped cords, damaged plug ends, missing plug prongs, and cracked casings on tool bodies. Tag a tool out of service if it is damaged.
  • Incorporate GFCI (ground fault circuit interruption) protection when using electric hand tools.
  • Place the GFCI closest to the point where the power is received.
  • Test the GFCI protection before use: Press the test button on the front of the outlet (Power to the outlet should now be removed).  Now, press the reset button on the front of the outlet (Power to the outlet should now be restored). The better tool for testing a GFCI is a portable GFCI plug tester; shown below.

Electrical work concerns or questions may be directed to your supervisor or to Electrical Safety Engineer, Todd Kujawa, at

Thank you for your attention to this important safety reminder.

Mary Logue

Associate Director, ESH&Q Division

Thomas Jefferson National Accelerator Facility

12050 Jefferson Avenue, Suite 602

Newport News, VA 23606