Forensic Electrical Engineering Blog #3

Past – Present – Future

3-Blog Series

By Jim Phillips, P.E.

 

Blog #3: Evolution in Forensic Electrical Engineering

There has been much advancement in the field of forensic electrical engineering since the days of Morse, Latimer, Edison and others. A few of the more significant advancements include:

  • Better Understanding of Electric Shock and Arc Flash Hazards
  • Codes and Standards
  • Computer Simulations

Personal injury that is a result of contact or exposure to energized electrical conductors is usually due to electric shock/electrocution and/or burn injury from an arc flash. In the early years of electrical power systems little was known about these hazards other than they can occur. Today, research, testing and new and improved electrical standards have greatly expanded the knowledge of these hazards.

From the early days of electric power, it was understood that electricity could result in injury and death from electrocution. However, there was limited research and data was available at the time to define exactly what happens when someone makes contact with energized conductors. How much current could result in ventricular fibrillation? How much current could lead to respiratory paralysis? To answer these questions and more, Charles Dalziel performed experiments on animals and humans to study the effects of electric shock. Through his extensive research, he published many papers beginning in the 1940’s and his paper “The Effects of Electric Shock on Man” [10 ] is widely cited by the electrical industry. Dalziel’s work has advanced the causes of electrical safety as well as electrical forensic analysis.

The Arc Flash Hazard has also existed since the very first electrical power systems were developed. An arc flash can occur when an energized conductor makes contact with another energized conductor or grounded surface. The thermal energy that can be released may be nothing more than an embarrassing pop, as sparks fly. It can also result in a massive explosion severely injuring or killing those in the vicinity.

Up into the early 1990’s, analysis methods that we have today for the arc flash hazard did not exist.

In the later 1990s, work by people like Doughty, Neal and Floyd, began to greatly improve what is known and provided an empirical method [ 11 ] that could be used to predict the severity of the arc flash.

This work became the catalyst for continued research that ultimately leads to the development of the Standard: IEEE 1584 – IEEE Guide for Performing Arc Flash Hazard Calculations, which was published in 2002. This landmark document provided more comprehensive empirically derived equations that can be used to predict and analyze the severity of the thermal effects of an arc flash. This standard and calculation method is quite important in the forensic investigation of arc flash accidents.

 

Codes and Standards

Codes and standards can also play a very important role in electrical forensic analysis. When an electrical incident occurs, the investigation will often involve reviewing relevant industry codes and standards. Answering questions such as which standard(s) apply and was a specific standard’s requirements correctly applied can be important in determining what happened.

Today unlike the early years, there are many different codes and standards for products, safety, applications, design and analysis. As an example, IEEE 1584 – IEEE Guide for Arc Flash Hazard Calculations can be used to predict the severity of thermal energy that results from an arc flash. NPFA 70E Standard for Electrical Safety in the Workplace can be used to determine if there was a breakdown in electrical safety practices. Another standard, the National Electrical Code can be used as a basis to analyze the electrical design of a system to see if it was in compliance. Hundreds of codes and standards exist today that were not available years ago.

 

Power System Analysis and Software

What if the equipment, component or building no longer exists because of the failure? An investigation of what is left is helpful but only part of the overall investigation. One of the more significant advancements in electrical forensic analysis is the development of new and better power system analysis methods. Using power system analysis and related software can be a valuable tool to not only predict future outcomes but to digitally recreate what may have happened. Advances in algorithms and software can be used by the forensic electrical engineer to simulate events such as whether a protective device failure was the result of too much short circuit current, predict whether power system harmonics are excessive, and even predict the severity of an arc flash. The analysis methods can play a vital role in forensic electrical engineering investigations.

 

Forensic Electrical Engineering – The Future

With the continued advances in smarter electrical systems, real time monitoring and development of more detailed modeling methods, being able to analyze data from electrical events to determine what caused them will continue. From lightning striking bell towers, to patent disputes of emerging 19th century technology to modern day computer simulations of catastrophic events, forensic electrical engineering has come a long way and will continue to evolve.

Electrical standards also continue to evolve and improve with every new edition based on what the industry continues to learn. Getting involved with the standards development process and making positive contributions ultimately can help people in the industry. Most of all, with each forensic electrical engineering case we learn more about what can go wrong. And when we know what can go wrong, changes can be made to help prevent it from happening again.

 

About Jim Phillips: Electrical Power and Arc Flash Training Programs – For over 30 years, Jim Phillips has been helping tens of thousands of people around the world, understand electrical power system design, analysis, arc flash and electrical safety.

Jim is Secretary of IEEE 1584 and International Chairman of IEC TC78 Live Working/Arc Flash. He has developed a reputation for being one of the best trainers in the electric power industry. Learn More

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References:

[ 10 ] Charles F. Dalziel – ‎1956 – ‎Effect of Electric Shock on Man, IRE Transactions on Medical Electronics

PP 44 – 62

[ 11 ] R. L. Doughty, T. E. Neal, and H. L. Floyd, II, “Predicting Incident Energy to Better Manage the Electric Arc Hazard on 600 V Power Distribution Systems,” Record of Conference Papers IEEE IAS 45th Annual Petroleum and Chemical Industry Conference, September 28–30, 1998.