May 2006 issue
By Michael Morse, Ph.D., University of San Diego

An expectation of low risk leads to a life-altering and career-ending injury for one unsuspecting electrician.

More than one electrician has told me — with almost some form of professional pride — that they have been shocked many times by 120V yet no harm has befallen them. A few old timers even talk of how they commonly test “low-voltage” circuits to see if they are live by touching the leads with the back of their hand. After all, as they are quick to point out, 120V isn’t dangerous — unless you get locked on. If you share this cavalier attitude, this case should make you think differently.

For one 45-year-old electrician, the day began like most work days. As an experienced electrician, he was tasked with making an electrical connection between an outdoor pedestal box and a 120V irrigation system controller.

The pedestal was the demarcation boundary between the legal domain of the electric utility and the property owner. The rear of the pedestal (electric utility side) was wired to a transformer. Two 120V phases and a neutral were connected from the transformer to the pedestal box. Mounted on a cement pad, the pedestal was fairly typical. There was ongoing construction, so the pad and road were on a dry, man-made earthen embankment spanning at least 5 ft above the surrounding unexcavated ground.

Two “car-stop” pipes, called bollards, filled with concrete and painted white and measuring 5 in. in diameter, were imbedded in the earth in front of the box to provide protection for the pedestal from traffic on the road. A ground wire was connected to the pedestal box and also connected to a ground rod that was driven into the earth a short distance from the cement pad. The back of the pedestal was locked with the appropriate electric utility tags.

No meter had yet been installed in the pedestal. As such, the gap between the electric utility’s domain and that of the property owner was not bridged — and the front of the box was not energized.

Upon beginning his work, the electrician touched one hand to the top of the pedestal box and the other to one of the bollards. He immediately noticed a mild electrical buzzing sensation and then broke contact. Asking his assistant to bring him an electrical tester to determine what might be energized, he proceeded to test between the pedestal and the bollard, giving him a clear indication that something was energized. Believing that the pedestal, which was obviously connected to a ground post, was not the source, he assumed the bollard was the culprit, chose not to touch it further, and went about his work.

While crouching down, he reached with his right hand to unlatch the front door on the pedestal while steadying himself with the other hand by grabbing the second bollard, which he quite reasonably assumed would not be energized. Suddenly, he found himself locked into an electrical circuit. Unable to free himself from the latch on the pedestal or let go of the bollard, the electrician fought to break free, using his legs to launch himself back into the middle of the road after 3 sec to 10 sec of electrical exposure.

Although the electrician was able to get up and move about immediately following the incident, his assistant called for an ambulance and notified the electric utility. Soon after, however, the victim began to experience muscle fatigue and shooting pains going down his arms and neck. This progressed to tightness in his shoulders and chest pain. Over time, the symptoms grew to include fatigue, dizziness, tingling, generalized weakness, and a “pin-and-needles” feeling. In the end, he was diagnosed with bilateral carpal tunnel syndrome as well as cervical degenerative disease. He also developed personality changes and experienced mood swings and anxiety.

I was contacted by the plaintiff’s attorney and retained as an expert to reconstruct the incident and explain how such a significant electrical injury could occur from a mere 120V contact that lasted only a few seconds.

In the lawsuit that followed, two major issues were challenged by the defense. First, it argued that the shock could not have occurred as the plaintiff testified, asserting that the plaintiff could not have gotten his hand locked behind the latch on the pedestal. Second, it maintained that the victim’s symptoms were extreme — if not ridiculous — for a mere 120V contact.

I made the group aware that a shock of 120V, especially when sweat is present, could have driven a current approaching or possibly even exceeding 500 mA into the plaintiff’s body. After reviewing a video frame by frame (see Photos) in which the plaintiff demonstrated how he grabbed the latch, it was obvious that he could have easily gotten a finger or two into such a position that the current flow, which vastly exceeded the human let-go current (14 mA for adult males), would have locked him in place until he was able to break free. Under the circumstances, a 3-sec to 10-sec shock was completely reasonable. More importantly, I offered testimony about a little-known primary response to electrical contact in which individuals can suffer a broad array of debilitating symptoms from even a brief contact with 120V. 

Although I could not state which of the plaintiff’s symptoms were primary or secondary, it was obvious from the chronology — coupled with the electrician’s lack of prior medical history — that the plaintiff’s injuries had a clear and absolute causal connection to the electrical injury that he suffered. Although the jury did find partial fault on the part of the plaintiff, it still returned a verdict of $3.3 million on his behalf.

To read the full story, along with  a table showing commonly reported long-term symptoms of diffuse electrical injury, visit http://ecmweb.com/content/dont-discount-danger-120v.