Abstract: A power line crew was locating an electrical fault in an underground power line. A service worker had isolated an underground line that he assumed went to a transformer box. Unfortunately, the service worker had isolated the wrong line. The line that should have been isolated was not marked. The service worker told the power line crew to hook up their portable, van-mounted cable fault locator to the underground line in the transformer box. He also told them that he had isolated the line. The lead power line worker then grounded the line and tested it. He determined that the line was deenergized. However, the fuse in the line was open, so the line was deenergized but not isolated. Believing that he had isolated the line, the service worker installed a new fuse to restore power to other customers. In the meantime, the power line crew had connected the cable fault locator to the 7200-volt underground power line. When the service worker replaced the fuse, the fault locator and the van in which it was mounted became energized. One of the members of the power line crew was electrocuted when he closed the van door. The other two employees received electric shocks when the fault locator became energized.