Two workers were installing shutters on the windows of a building. One was about six feet (two meters) above the ground on a scaffold. The other began to climb a metal ladder so he could hand an electric drill to his co-worker, but reaching the third rung, he received a fatal electrical shock.

Investigators found the drill and extension cord were defective. The third prong, required for grounding, was missing from the extension cord. The frame of the drill was not double-insulated. A conductor on the grounding wire was making occasional contact with the energizing wire. This contact caused the grounding wire and the drill’s frame to become energized.

Another dangerous work practice contributed to this fatality: using a metal ladder for electrical work.

Pre-inspection of all tools should be a routine procedure. Make sure your workers examine power tools for damage and defects. These include frayed cords, loose or bent plugs, missing third prongs, damaged insulation and other problems that could lead to electric shock. An electrical power tool must either be grounded with a three-prong plug or double-insulated.

Once a tool has been determined to be defective it must be removed from service. Workers should be instructed how to tag a tool to remove it from service, where to deliver it for repair by a qualified person and how to obtain a replacement.

Are non-metal ladders available to your workers for any electrical work they may be required to do, even changing a lightbulb? Many large construction companies have quit using metal ladders to avoid this hazard.