Like so many others before it, this case involved a host of unknowns — starting with an unsuspecting victim walking into what seemed like a typical job-site scenario until a hidden hazard made its abrupt entrance. Getting up and going to work as he’d done every other day of his adult life, the complainant was a hardworking 40-year-old man who did cement work for a living. He had never performed electrical work; his only connection to what happened that day was being in the wrong place at the wrong time.
Setting the stage
On the day of the injury, the worker was tasked with installing a bollard on a construction site. He placed the bollard, filled it with cement, cleaned up the area, and then completed some finishing work, which included a bit of painting.
When he was finished, he walked over to an area where a guardrail stood adjacent to a signpost to do some cleanup. As he leaned over the railing, his stomach came to rest on the guardrail. With his left hand, he pushed against the guardrail to stabilize himself. To gain more stability, he pushed his right hand against the adjacent signpost. It was then that he received the electric shock. Immediately, his right arm snapped back from the point of contact. Although he did not fall to the ground, he recognized this sensation as an electric shock and knew he’d been injured. He had no visible electrical burns on either hand — the only marks were red streaks where his stomach had contacted the guardrail.
For most people, this type of brief electric contact (although annoying and painful) would have had little to no long-term effect. Unfortunately, the complainant in this case was not so lucky. In his testimony, a coworker noted that the victim appeared very tired after the accident and was much less active for the rest of the work day. Per the victim’s testimony, his heart was racing after the initial contact; however, it somewhat normalized as the day progressed.
He went to the emergency room that evening, presenting with muscle cramps; pain in his chest, back, and arm; and a headache. Although his ECG was normal, by the next day, symptoms had expanded to include body aches and muscle spasms on his whole right side. Over the next few months, symptoms grew to include broad neuropathic pain, sensory loss, generalized fatigue, and numbness. After two years, his condition remained stable yet unresolved — with the predominate long-term symptoms being right side neuropathic pain.
After the incident was reported, an inspection of the site revealed that when the guardrail had been placed, a conduit containing power conductors serving a lighting load had been breached. This energized the guardrail to 277V. As a result, touching the guardrail was no different than touching an exposed wire. The nearby signpost provided an excellent return path to ground. Presumably, the victim did not receive a shock when he first contacted the rail because his shoes provided adequate insulation, preventing current flow from his contact with the rail to ground. The victim brought suit against multiple defendants, including the fencing company, the construction company, and the electrical contractor.
Although there was little doubt that the complainant had been shocked, the standard defense position in this and similar cases is that the shock was minimal and that the reported symptomatology was simply not consistent with the shock received. The defense neurologist relied on the absence of burns as indicative of a lack of injury. Furthermore, it was noted that an electromyogram (EMG), a study of the electrical activity in muscles that sometimes registers as abnormal after an electrical contact, had yielded no indications of injury. The defense orthopedic expert offered the opinion that the complainant’s injuries were limited to muscle strain and should have resolved within three months post-incident.
I was brought in as a plaintiff’s expert and asked to analyze the shock received. The testimony of the victim and all physical evidence indicated that the shock received was brief (probably just a fraction of a second) and that the voltage of the shock was 277V with entry at his belly and exit at his right hand. Such a brief shock would tend to impart very little energy. (If that amount of energy was added to a cup of water, for example, it would barely increase in temperature.) Internal thermal injury would not be expected. Assuming an average body resistance of 1,000 ohms (which is a good starting point for analysis and is often used by both plaintiff and defense experts), by applying Ohm’s law, the current flow would have been approximately 277mA. (Note: Body resistance can vary widely with circumstances. As such, current calculations should be approached very cautiously.)
Although the defense experts had substantial credentials, they lacked experience and understanding of the effects of electricity on the human body as broadly reported in current literature. In fact, it has been decades since the lack of external burns has been used to predict a lack of internal injury. Burning takes both time and current density.
Even with shocks that impart significant energy, wet skin or a large entry area can reduce the energy imparted per square inch at the skin surface and thus prevent burning. As such, the defense expert was in error when he used the absence of burns to prove a lack of injury. The absence of subjective diagnostic evidence is also quite common in these cases. Although the mechanism of injury may still be in question, there is no dispute that internal injury can occur without appearing in standard diagnostic testing. My analogy for this situation is like saying no one suffered a broken leg before there were X-rays to prove the bone was broken. We have just not developed the technology yet to accurately image the internal injury from the current.
At the end of the day, the case settled for an undisclosed amount. In looking back at the circumstances surrounding this case, several lessons can be learned.
First, it’s not the last shock we should be concerned about but rather the next one. Too many electrical professionals tell war stories of being shocked in the field and how they lived to tell about it. Because they weren’t injured that particular time, they use that experience as a predictor of injury for the next potential shock. We now know that even minor shocks can cause major internal injury. Any tissue along the pathway of the current can be damaged, and broad path-related symptomatology is known to occur even after low energy shocks like this one.
Second, this case proves the point that vigilance must be a part of any work environment that involves digging and construction, especially when conductive structures are involved. Those who placed the underground conduit so shallow and close to the road should have foreseen the potential for a breach later in the construction process. The bottom line is those who placed the guardrail should have paid much greater attention to where they were digging and what they came into contact with.
Sadly, this is yet another case of a stranger’s path crossing the paths of others in a negative way because proper caution was not used (see Electrical Work Has Far-Reaching Effect). Because the installing party failed to exercise proper diligence and responsibly assure the safety of those around them, one unlucky cement worker will most likely be condemned to suffering chronic pain and inferior quality of life for the rest of his days.
Morse is an academic, researcher, and consultant. He has reviewed hundreds of electrical injury cases. He is a full professor of electrical engineering at the University of San Diego. Find more information on electrical injury at http://www.electricalinjury.com.
SIDEBAR: Electrical Work Has Far-Reaching Effect
After having studied hundreds of electrical contacts that have led to death or debilitating life-altering injuries, with each new case, this author has gained greater clarity on the topic of electrical safety. He repeatedly tells his students that they should never lose sight of the people they will never meet who will come into contact with what they will build. One bad choice, one moment of inattention, or one cut corner can lead to the injury or death of an unsuspecting stranger. It is this type of random crossing of paths that must lead those who work with or near electricity to recognize just how much responsibility they have to so many innocent bystanders.