Electrocution

Edgardo López, P.E., CFEI

The Assignment: 

EDT was contacted to determine the cause of an electrocution.  The incident involved the electrocution of a pedestrian.

EDT Analysis and Findings: 

A pedestrian was electrocuted when he came in contact with an energized steel guy wire near a sidewalk.  A steel guy wire is used to help hold a power pole in the upright position.  

EDT began the examination of the electrocution with an assessment of the area where the incident took place.  The assessment included the identification of the electrical components on the power pole, the installation methods used to install the components, as well as measurements of the distances and clearances between energized components and distance and clearances between energized and de-energized components.  An independent land surveyor was contracted to measure the distances and clearances of the components on the power pole.  

Police records, including photographs taken at the scene the day of the incident and news reports were requested, gathered, and reviewed. The importance of having this information is it aids in the ability to document the area of the incident as it was when the incident took place.

Electrical utility personnel responsible for the maintenance and operation of the power system in the area were contacted for the purpose of obtaining information related to the incident.   This information included their maintenance and operational practices.  

The land surveyor measurements and the installation of the electrical components in the area of the incident were compared to state and federal applicable codes.  

The measurements taken by the land surveyor, which included the distances of all the components on the power pole as well as the clearances between energized components and between energized and de-energized components, were found to be within the requirements of the codes.  

The EDT investigation established that the power pole and power lines installed in the area of the incident had been changed after the incident.  The most noticeable change was the removal of the guy wire which was no longer installed on the power pole.

Using the police photographs, EDT was able to evaluate the installation of the guy wire at the time of the incident.  EDT was able to determine that the guy wire was not installed as required by the applicable codes. These safeguards would have included the installation of an insulator at the top of the wire or to have the guy wire effectively connected to the ground of the electrical system.  The installation of either of these safeguards would have resulted in the guy wire not becoming energized and would have prevented the electrocution of the pedestrian.  Based on EDT examination it was found that the cause of the pedestrian electrocution was the inappropriate installation of the guy wire.