Case Study
A 29-year-old male welder was assigned to work on an outdoor concrete platform attached to the main factory building. He wheeled a portable arc welder onto the platform. Since there was not an electrical outlet nearby, he used an extension cord to plug in the welder. The male end of the cord had four prongs and the female end was spring-loaded. The worker plugged the male end of the cord into the outlet. He then plugged the portable welder's cord into the female end of the extension cord. At that instant, the metal case around the power cord plug became energized, electrocuting the worker.
An investigation showed that the female end of the extension cord was broken. The spring, cover plate, and part of the casing were missing from the face of the female connector. Also, the grounding prong on the welder's power cord plug was so severely bent that it slipped outside of the connection. Therefore, the arc welder was not grounded. Normally, it would have been impossible to insert the plug incorrectly. But, since the cord's female end was damaged, the "bad" connection was able to occur.
To prevent this from happening to you or one of your co-workers, use these safe practices:
- Thoroughly inspect all electrical equipment before beginning work.
- Do not use extension cords as a substitute for fixed wiring. In this case, a weatherproof receptacle should have been installed on the platform.
- Use connectors that are designed to stand up to the abuse of the job. Connectors designed for light-duty use should not be used in an industrial environment.
Knowledge Check Choose the best answer for the question.
1-2. Do not use extension cords _____.
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