Once again it is Electrical Safety Month, and NFPA 70E continues to be at the forefront of electrical safety. However, not enough people are properly trained based on the requirements of this standard. Below are several investigations that I conducted over the years: one case where training saved two lives, and several others where a lack of training led to tragedy.
Absence of voltage—a near-miss
Training works! NFPA 70E 120.5 outlines all the steps for the process of establishing and verifying an electrically safe work condition. One of the final steps is to verify the absence of voltage, and here is a prime example of why that is so important.
About 15 years ago, I was conducting a series of NFPA 70E training programs for a large company and running a new group through about every month. During one program, the lead person said the “new” requirement of establishing an electrically safe work condition saved two lives the previous month. I was a bit stunned.
He said they had two contractors in for their annual maintenance of an older open bus. They opened the one and only disconnect and were about to begin, when he said the words from my training class echoed in his mind as he yelled out, “STOP! Wait a minute. You and I know we’ve done this many times before but we have a new practice. Wait until I get my meter and test the bus that we already know is dead.” After testing, he was horrified to find it was still energized. Looking at the switch that was in the “off” position, he opened it to find it had failed in the closed position.
Missed sources—permanent injury
An electrician was adding a new circuit to the A-side of a 4,160V double-ended substation. He opened and locked out the A-side main and the tie circuit breaker and began his work. On Friday, he went home for the weekend. When he returned on Monday, he saw his locks still in place and picked up where he left off. Except, boom! He was severely injured in an arc flash.
He failed to review the electrical drawing on a table nearby. The drawings clearly indicated a back-tie that could connect the A-side from a different source. He also failed to recognize this was a “complex” lockout/tagout with many requirements. Over the weekend, the operations crew closed the back-tie since it was not locked out, energizing the bus. The electrician also failed to re-verify the absence of voltage when he returned. It came down to a failure in training.
Back in the early 1990s, I had an industrial facility as a client and got to know their maintenance person rather well. One day, I received a call that he was involved in an “electrical explosion” (the term “arc flash” had not yet been introduced). He had third-degree burns over a large part of his body and ultimately succumbed to his injuries.
The facility had been experiencing low-voltage conditions, so he was conducting voltage measurements on the 480V system to determine whether transformer taps should be changed. One location was a dry-type transformer, from which he removed the cover (bad idea) to take measurements on the 480V side. However, it was a 4,160V-to-480V transformer, and he connected the meter to the 4,160V side. Today, NFPA 70E 110.4 requires that test instruments have a proper rating and only qualified persons perform such tasks. Back then, however, most were unaware of NFPA 70E and electrical safety training was minimal at best.
Change in scope—fatality
A data technician was conducting an energy audit, which required downloading energy usage data from data ports located on the outside of several rooftop air handlers. One unit did not have an external port, so he opened the access cover to see if it was mounted inside. It was. He crawled in about chest-deep to connect his laptop and grabbed a component to better position himself. Unfortunately, the component was energized, and he died from electrocution.
The root cause was a lack of basic electrical safety training as an unqualified worker. He did not recognize that a change in scope—crawling inside the equipment—was not part of his job. Recognizing a scope change like this is difficult because of the philosophy that we must complete the job. However, this culture is slowly changing and people are recognizing that if something changes and is no longer familiar, it is prudent to stop and ask how to proceed.
Although electrical safety continues to improve, accidents and fatalities still occur. Ensure employees are trained and receive refresher training on a regular basis—or I may have another investigation.