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715 Electrical Safety for Technicians and Supervisors
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Case Study

A 29-year-old male maintenance worker was found at 3:45 a.m. lying on his back and convulsing. Beside him were an overturned cart and an electrical welding machine, both lying in a pool of water on the concrete floor. Arcing was visible between the welding machine and the floor. The worker was transported to the closest hospital, where he was pronounced dead.

An examination of the welding machine showed that there were exposed conductors in the machine's cables. There were numerous cuts and scrapes in the cables' insulation. On other parts of the machine, insulation was damaged or missing. Also, the machine did not have a ground connection.

Investigators concluded that the maintenance worker was electrocuted when he tried to turn off the welding machine, which was sitting on the cart. The metal frame of the machine had become energized due to the damaged insulation. When he touched the energized frame, he completed the conducting path to the ground. The current traveled through his body to the ground. Since he was probably standing in water, the risk of ground fault was even greater.

You must take steps to decrease such hazards in your workplace:

  • Ground circuits and equipment.
  • Keep all equipment in good operating condition with a preventative maintenance program.
  • Never use electrical equipment or work on circuits in wet areas. If you find water or dampness, notify your supervisor immediately.

Knowledge Check Choose the best answer for the question.

3-5. What is recommended to keep electrical equipment in good working order?