The Forensic Electrical Engineer is often called upon to determine if electricity was involved in the cause of a fire. Events occur within an overall context, so an electrical engineer must have an excellent working knowledge of all fire causes and origins, similar to that of a Certified Fire Investigator (CFI).
The Electrical Engineer’s certification is Registration as a Licensed Professional Engineer, designated by the initials P.E. after one’s name.
CAUSE & ORIGIN
Determining the origin of a fire is a process similar to that used by a CFI.
The Electrical Engineer is trained to design electrical circuits with an emphasis on all of the ways that electricity can cause excessive heat and arcing, and to understand the way materials react to the heat normally and catastrophically produced, intentionally or as a byproduct of the use of electricity.
Pyrolysis is slow low temperature conversion, normally of wood or plastic, from its useful state to one of elemental carbon or charcoal that can proceed to ignition without open flame, arcing or any other external cause.
Often an electrically-caused fire is accompanied by evidence of arcing, however sometimes circuit components overheat or experience very low energy arcing that merely heat surrounding insulation or tangential wood to the point of ignition. The investigator should immediately recognize that pyrolysis is involved in the cause of the fire.
When lightning-initiated electric current flows through a building’s electrical wiring system, it often requires experience to recognize that the current follows the normal laws of electricity, in spite of the seemingly strange evidence left behind.
Besides fires, there may be arcing damage to heating and plumbing systems, electronic appliances, wall receptacles, and sometimes to the circuit breakers in the service panel.
When arson may be suspected, the Fire Marshal may request a Forensic Electrical Engineer to inspect the facility’s electrical systems to eliminate them as a potential energy source that might have caused the fire in question.
FIRE CAUSE TRAINING
After exposure to fire theory through fire investigation courses, or physics, chemistry and engineering thermodynamics courses, the best way to understand fire cause is to recreate various ignition processes in a scientific environment.
In general, starting wood stove, debris, camp and brush fires can foster the understanding of fire ignition principles.
The engineer should be familiar with the use of torches used for soldering, and the cutting and welding of metals. Finally, an understanding of arc behavior gained through arc-welding proficiency proves valuable.
DIGGING OUT A FIRE
If it is suspected that electricity is involved in the cause of a fire, the Electrical Engineer should work concurrently with the fire investigators and fire sniffing dogs to dig out the fire. The electrical engineer brings his own search criteria to the investigation and will often see indicators that have no relevant meaning to the ordinary investigator.
Fire Cause and Origin
Power Wiring and Circuits
National Electrical Code (NEC)
General Order 95
Electrician Trade Practice
Lock Out / Tag Out
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