Methodology and Tools for Forensic Engineering Analysis of Electrical Shocks
Keywords:Electrocution, electrical shock injury, leakage current, resistance, impedance, insulation, stray voltage, electrophysiology, grounded conductor, grounding conductor, electrolyte, ground fault circuit interrupter, GFCI
Forensic engineering analyses of electrical shock incidents are challenging because many factors need to be considered to understand how and why the incident happened. The goal is to determine how and why the victim’s body became part of an electrical circuit that caused the shock injury. To do this, the engineer needs to determine, if possible, all of the connected portions that combined to make the complete circuit at the time of the shock, including the energized and non-energized conductors. Then, failures (defects) of components and violations from standards by parties involved with manufacturing, installing, inspecting, operating, and servicing the electrical circuits/systems involved need to be determined and their relation to the cause (failure-modes) evaluated. There will often be multiple circuits in the vicinity of the shock victim, some of which are pertinent to the shock and others that are not. These circuits need to be analyzed and non-pertinent circuits ruled out. When the pertinent circuit is determined, all the conductive elements and connections that form the (often three-dimensional) circuit should be identified. This paper outlines the scientific methodology and tools, logical decision analyses, and procedures for performing a shock analysis and provides examples based on actual investigations.
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