Evaluation of safety grounding practices for maintenance work on de-energized transmission lines

The effectiveness of different personal protective safety grounding configurations for transmission lines was investigated by the Puerto Rico Electric Power Authority with assistance from the US Bureau of Reclamation. Seven different safety-grounding configurations on a 115-kV line at an H-frame wood pole structure were tested by energizing the line and initiating high fault currents in the safety ground cables. The test methods are presented and the grounding configurations rated for effectiveness in controlling worker exposure voltages. The test results have greatly contributed to alerting supervisors, line and ground crew personnel of the electric shock danger associated with certain grounding schemes and are being used to evaluate safety grounding practices for maintenance work on deenergized transmission lines.