A n employee was climbing a metal ladder to hand an electric drill to the journeyman installer on a scaffold about 5 feet above him. When the victim reached the third rung of the ladde , he received an electrical shock that killed him. An investigation showed that the grounding prong was missing from the extension cord attached to the drill. Also, the cord s green grounding wire was, at times, contacting the energized black wire. Because of this contact with the "hot" wire, the entire length of the grounding wire and the drill s frame became energized. The drill was not double-insulated.
avoid deadly incidents like this one, take these precautions:
Make certain that approved GFCIs or equipment grounding systems are
used at construction sites.
Use equipment that provides a permanent and continuous path to ground. Any fault current will be safely diverted along this path.
Inspect electrical tools and equipment daily and remove damaged or defective equipment from use right away.
❑ Use the right tool correctly—Use tools correctly and for their intended purposes. Follow the safety instructions and operating procedures recommended by the manufacturer. When working on a circuit, use approved tools with insulated handles. However, DO NOT USE THESE TOOLS TO WORK ON ENERGIZED CIRCUITS. ALWAYS SHUT OFF AND DE-ENERGIZE CIRCUITS BEFORE BEGINNING WORK ON THEM.
❚ Use the right tools and equipment.
❚ Do not work on energized circuits.
❑ Protect your tools—Keep tools and cords away from heat, oil, and sharp objects. These hazards can damage insulation. If a tool or cord heats up, stop using it! Report the condition to a supervisor or instructor immediately. If equipment has been repaired, make sure that it has been tested and certified as safe before using it. Never carry a tool by the cord. Disconnect cords by pulling the plug—not the cord!
❑ Use double-insulated tools—Portable electrical tools are classified by the number of insulation barriers between the electrical conductors in the tool and the worker. The NEC permits the use of portable tools only if they have been approved by Underwriter’s Laboratories (UL Listed). Equipment that has two insulation barriers and no exposed metal parts is called double-insulated. When used properly, double- insulated tools provide reliable shock protection without the need for a third ground.
Don’t work on energized circuits like this one! Always follow correct lock-out/tag-out procedures.