Dead work is vulnerable to unexpected power sources

In an electrical installation at the work location de-energizing is only one part of creating an electrically safe work condition for the duration of the work. Unexpected sources can occur, specially when working on overhead lines. Some activities are sensitive to the unexpected sources and in these cases, depending on the electrical energy available, these sources could cause injury or death. The paper relates about an fatal injury occurred working on a de-energized overhead line. Generally there is uncertainty about exposure to the unexpected sources. When there is suspect on the electrical energy not negligible, it is wise to add temporary protective measures. Many times, it is a decision made in the field and entrusted to the person performing the work. An essential progress of the safety procedures should be to set concrete guiding criteria at the standard level for detecting by conventional tests at least the steady unexpected sources. This integrative rule could be added to the canonical requirements of de-energized work like last one in order of execution. Consequently in the cases of sensitive works this integrative rule could help for decision making on choosing temporary protective measures additional to the dead working procedure or on adopting the live working procedure. © IEEE 2010.