Electrical Arc Injuries: A Complex Multi-Physical Injury Dynamic

Staying up to date with new information and following electrical safety guidelines is crucial to reduce risks and prevent injuries.

By Nallely Ramirez and Suma Gangidi, Contributors

Electricity plays a vital part in our everyday lives, powering everything from our homes to the street lamps to handheld devices we use daily. With evolving technology, electricity has continued to play a growing role in order to meet such demands. However, this inexorable increase in risk gives rise to human risk of electrical power exposure.

With both non-fatal and fatal cases reported every year, electrical injuries are a prevalent issue. One of the hazards that may result in debilitating or fatal injuries is close exposure to high-energy electrical arcs.  Often electrical arcs are called arc flashes because of the intense light emitted. Although the light may cause ocular injury, exposure to the light is not necessary to experience injury.

SAFE DISTANCE GUIDELINES

Considerable effort on the part of engineers and trauma physicians has been invested in determining safe distance guidelines for workers involved in electrical power equipment. In particular, electrical safety committees with the National Fire Protection Agency (NFPA) and Institute of Electrical and Electronics Engineers (IEEE) have published guidelines that can be found in NFPA 70E and IEEE 1584. As a rough approximation, an “arc flash boundary” guideline is based on the incident heat pulse energy level of 1.2 calories per centimeter squared (cal/cm²), which is the threshold for the onset of a second-degree burn.

Although the real partial thickness thermal burn distance boundary is certainly a function of the power delivery capacity of the electrical power source and environmental factors, such as closed vs open space, acoustic energy absorbing surfaces, the specific heat of the air (i.e., humidity), ambient temperature and normal barometric pressure of the site, this guideline is a good one to follow.

ELECTRICAL ARC INJURIES

There are other dimensions of the arc flash injury that are important to consider as well.  The electrical arc is a hot ionized conducting gas that is rapidly expanding. It is possible for a worker to be close enough to an arc flash to experience an electrical shock. This ionized gas, like lightning, can transmit electrical current and cause an electrical shock injury.

As a person approaches through the arc flash boundary, the next risk boundary is referred to as the “Limited Approach Boundary.” At the limited approach boundary, there is the added risk of electrical shock via contact with the active electrical arc.  Another contact possibility is related to the strong magnetic field pulse driven by the rapid transient electrical arc pulse.  Access to the restricted approach area requires the proper equipment and training.

MEDICAL PROBLEMS

Survivors of electrical arc flashes can manifest a range of medical problems from those associated with burns, high-pressure blast injuries and electrical shock.  Level 1 trauma centers are well-equipped to provide the needed emergency care and triage. Occasionally, other medical problems become more noticeable with time. Thus, it is vitally important to adhere to safety standards.

As technology continues to advance and become more ingrained in our everyday lives, we will need more power to generate the electricity needed to handle the demand.  The greater amount of power we work with will lead to greater electrical injury risks and hazards. Especially when discussing magnetic field pulses, the increase in power increases the pulse strength.

While existing precautions have progressed the electrical safety for workers, it is important to address the gaps that exist. With the severity of such injuries being fatal, it is instrumental to continue to learn more about these hazards and take preventative measures. This can be done by staying up to date with new information relating to electrical safety and ensuring the guidelines that do exist are being implemented and followed. ESW

References

  1.  NFPA 70E Standard Development
  2. Lee, R.C. “Injury by Electrical Forces: Pathophysiology, Manifestations and Therapy.” Current Problems in Surgery 34(9): 677-765, 1997.
  3. Lee, RC., Zhong, MH., Shih JX, Chen CT. “Occupational Electrical Injury – Preface” Annals of the New York Academy of Science, Vol. 888, pp. IX-XI, 1999
  4. Bier M, Chen W, Bodnar E, Lee RCBiophysical injury mechanisms associated with lightning injury” NeuroRehabilitation. 20(1):53-62, 2005

The authors, Nallely Ramirez and Suma Gangid, represent the Chicago Electrical Trauma Rehabilitation Institute (CETRI). CETRI is a non-profit organization,  incorporated in 2009 to centralize the administrative operation of an ongoing 20-year multidisciplinary medical service and research collaboration to better understand and treat electrical burns.  Learn more at www.cetri.org.

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