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The Case of the Locked Out Switch that Wasn't

The Case of the Locked Out Switch that Wasn't

Communication breakdown between contractors leads to untimely death of electrician working on "dead" equipment.

When the Maricopa County Sheriff's Department in Phoenix decided to build a new laundry and food prep facility, the scope of work would certainly not be considered out of the ordinary. On this particular project, the electrical portion of the job would require the services of both an electrical contractor and a more specialized high-voltage utility-type contractor.

The main switchboard for this facility was housed in the mechanical building and consisted of a 4,000A distribution center fed from several large transformers on the exterior of the building. These transformers were fed from a disconnect switching mechanism, also located on the grounds. The electrical contractor was responsible for all work inside the building, while the high-voltage contractor handled installation of the transformers, switching equipment, and high-voltage power lines from a utility distribution point located about a mile from the site.

The project was well on its way to completion when the unthinkable occurred. A young electrician working for the electrical contractor was severely shocked, as a result of working on what he thought was “dead” equipment. After the accident, I was retained by the insurance carrier for the general contractor (GC) to ascertain the company's degree of responsibility in this unfortunate death. As part of my forensic investigation, it was important to recreate the circumstances leading up to the incident.

What went right and wrong

It all started when the local electric utility registered a complaint with the electrical contractor, stating that the bare ground wires it had previously installed were done so within the utility's “cable pulling section” of the switchgear cabinet (Photo 1). They wanted the electrical contractor to come back out and relocate them to the ground bus in the adjacent bay (the utility “pull” section for their incoming lines from the transformer banks), as shown in Photo 2. The transformers and disconnect switch, along with the high-voltage power lines, had been installed and tagged out. Although there was no date on the lockout tag, I was told by a project manager for the general contractor that the switch had been installed for several weeks before the incident took place — and that the tag had been installed on it immediately after its installation (Photo 3). At this point, no city inspections had occurred, and no release of service had been issued by the Maricopa County Inspection Office and the City of Phoenix, along with the electric utility (Arizona Power), who had subcontracted the work to the outside high-voltage contractor.

After notifying the general contractor of the situation, the electrical contractor was granted approval to relocate the ground wires as requested. Two journeyman electricians were assigned the task. (It is my understanding that the pair had been performing minor work on the switchgear for a few weeks prior to the day of the incident — inside and outside the switchgear. Apparently, they assumed the gear was still de-energized. In all fairness, this would not be an illogical assumption, considering the fact that electricians are usually kept in the loop when gear goes “hot.”) Both electricians proceeded to open the cabinet doors at each end of the switchgear — each starting at one end of the row of cabinets — to perform the relatively simple task of relocating the wires.

Unbeknownst to them, however, the high-voltage contractor team was simultaneously performing its work a mile from this site. This group's goal for the day was to make the final connections to the energized electric utility power lines. Unfortunately, based on discussions with on-site witnesses, no one from the high-voltage contractor crew gave notice that they were “testing” the lines, nor did they go downstream to assure that all of the downstream disconnects were in fact locked out and properly tagged. This created a dangerous situation for the two electricians working inside the building because once the main disconnect switch feeding the transformer banks was closed, power flowed through the circuit and energized the bus within the cabinet the young electrician was working in.

When he went to lower himself into the pit area in front of the bay, and begin the task of disconnecting the ground wires to relocate them, he leaned against the energized bus bars (Photo 5). As he screamed out in pain, his fellow electrician immediately ran to offer assistance, but quickly realized there was nothing he could do to help. He knew better than to try and pull his injured coworker to safety, which would have placed himself in the path of the lethal current as well. After less than a minute, the upstream protective devices on the electric utility pole (reportedly located nearly a mile away) operated, de-energizing the circuit and bus bars in contact with the electrician.

Tragically, he'd already received extensive second and third degree burns over most of his body. Although paramedics arrived shortly after and transported him to the nearest hospital burn ward, the electrician succumbed to his injuries two days later, mostly as a result of internal burns to his vital organs.

The investigation

Hired by the GC's insurance company to determine liability in this case (Photo 4), I drew several conclusions from my review of the data and circumstances leading up to the accident. Upon review of the GC's policy and procedure manuals, correspondence between the subcontractors and the GC, and analysis of the plans/specifications, I determined that the GC was aware that this corrective operation was to take place and had been assured by the electrical contractor that all necessary precautions had been taken prior to the commencement of work. Therefore, I believed the GC was not responsible for the accident.

The reality is the electrical contractor apparently ignored one of the most important safety rules ever written: “Treat all wires and equipment as if they are hot until proven otherwise.” Had the electricians assured that all lockouts on the feeder system were in fact open and locked out, the accident would not have taken place. They should have placed a “Man Working” tag on all disconnects in the circuit path, notified the high-voltage contractor that they were going to be working in the cable pull section of the switchgear cabinet, and installed temporary grounds from bus to bus and bus to ground. At the very least, if the two electricians had merely installed temporary grounds at their work location, the upstream disconnects and fuses would have tripped or blown in a very short period of time, most likely resulting in a burn injury rather than death.

After relaying my findings to the attorney, I was not called for any further investigation or testimony. The state workers compensation board took over the case and ultimately settled with the surviving family members.

The lesson

During my investigation, I had the opportunity to discuss preventive methods with the GC to avoid this type of accident in the future. I stressed that when a lawsuit is written, everybody is named on the initial suit. This allows for the attorney to be sure that anyone even remotely associated with the project is investigated for potential liability.

I suggested to the GC that he review his safety manuals and procedures with each and every one of his subcontractors and require more thorough communication on any similar work in the future. There's no such thing as too much information or communication when lives are at stake, even on the simplest of jobs.

Nicholas, a forensic electrical expert, is president of JNLV Consulting Co., Inc., in Las Vegas.

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