Don’t Do This: Lessons Learned in the Field
I was so excited when I became a journeyman lineman in the early 1970s. In those days, there was no such thing as a journeyman ticket – a union member or business agent would let you know that you had arrived. Seniority alone was the driver.
I was a union lineman in IBEW 84/896 located in Macon, Georgia. As there was no junior apprenticeship development program at the time, the senior linemen on the crews taught young apprentices. Apprentice school consisted of a two-week class to determine if an apprentice could climb a 40-foot pole well enough to become a journeyman. There was also a small segment of the class dedicated to building transformer banks and framing poles. That was it. The real learning began after being promoted to journeyman.
I was fortunate to learn from excellent, experienced senior linemen. Most had 10 years of crew experience or more, and I was privileged to work with them for the first five or six years I was on a line crew. Back then, we had six-man crews: three linemen, an apprentice, a winch truck operator and a foreman who was part of management (i.e., not a working foreman). The foreman was in charge, and he doled out a lot of advice to younger crew members as their on-the-job training was advancing.
Don’t Do This: Scenario 1
All of this was well and good until a task came along that no one on our crew had much experience with. For example, on one occasion, a customer simply could not find time for a scheduled outage that would allow us to relocate a bank of transformers feeding the building. So, the crew members put their heads together and devised a plan to parallel the YY bank with another bank. We set a pole and built a bank of 100-kVA transformers about 75 feet away. After the new bank was completed, we closed the switches, heated up the bank, and checked the voltage and phasing to ensure everything was correct with the existing bank. Everything looked good.
Next, we pulled a piece of 4/0 quadruplex from the new bank to the existing bank pole to connect the service from the new bank to the existing quadruplex. We then energized the existing bank, cutting the existing service in the clear. We had successfully completed a similar task at other locations in downtown Macon when converting the system from 4 kV to 12 kV – but this time we overlooked one step. Once the voltage and phasing checks had been completed, a lineman at the new bank pole opened the cutouts and de-energized the bank. At the same time, the old bank was still energized and serving the customer. While I was on the existing bank pole, I was instructed to recheck the markings on the quadruplex, confirm everything was correct, and make the connection from the new service to the existing service. The weatherproof jacket was removed, and we used H-frame compression connectors.
The problem was that when I connected the new and old services, a flash occurred that nearly scared me to death. I thought I had made a phasing mistake, but it turns out that none of us on the crew had realized that heating up the transformer from the secondary coil side was just like picking up a large load. That’s why the flash occurred, not because of a fault. Afterward, our resident engineer asked us why we didn’t have the transformers energized on the new bank. It was because we’d energized the new bank to parallel and had never had problems with that in the past.
So, another lesson was learned, even by the senior linemen on the crew. We had never asked about or verified the task we were to perform, and we had assumed everything would be fine using the procedure we chose. Had we asked for clarification, we could have avoided the incident altogether. Luckily, in the end, there was no injury to anyone other than some embarrassment.
Don’t Do This: Scenario 2
The next real-life “don’t do this” scenario I want to share with you involved a crew building a two-transformer open delta UD bank. We were continually building these banks to feed sewerage lift points in subdivisions that did not have three-phase primaries when they were designed and cable was installed. After load surveys were conducted, engineers decided that splitting the loads of the total number of houses into two different phases would be adequate and not cause a load imbalance on the overhead system that fed underground.
Keep in mind that because of terrain and land elevation, gravity flow of sewage is not always possible. Inevitably, some of it must be pumped uphill. When we were building these types of banks, a three-phase lift pump would typically be needed on the backside of the subdivision.
A two-transformer open delta bank must be built with only two phases available. I’ve never personally had a problem installing one, but in this cautionary tale, a crew learned a valuable lesson after one of their crew members was nearly killed by an energized bank. The crew had been instructed to build a two-transformer open delta bank – although they’d never installed one before. The incident report stated that the crew was following the company specifications book as required. To use the entire coil for the high leg on delta service, the neutral spade in the power transformer of the two-transformer bank had to be isolated. Next, the specifications book stated that the transformer tank ground must stay in place after removing the neutral strap from the transformer bushing. The crew missed that step.
As a result of the tank not having the concentric neutral or neutral bus attached to the system neutral, the internal high-side coil needed to be connected to the system neutral by the tank ground. That means the tank had primary voltage potential given that the high-side primary-side coil was internally attached to the tank. When elbows and bushings energized the transformer, the tank was also energized. Unfortunately, one of the crew members contacted the power transformer and the lighting transformer. He didn’t sustain any severe injuries, but again, lessons were learned. First, if you’re unsure, stop the work you’re doing and ask for clarification. And second, be sure to test and verify that all connections have been made per your company’s specification requirements.
Conclusion
I feel that stories like these are worth passing along to new lineworkers who are learning the trade as I did many years ago. You can read about other events I’ve witnessed – and the lessons learned from them – in my book, “Legends of an Ole’ Lineman.”
About the Author: Danny Raines, CUSP, is an author, an OSHA-authorized trainer, and a transmission and distribution safety consultant who retired from Georgia Power after 40 years of service and now operates Raines Utility Safety Solutions LLC.
Learn more from Danny Raines on the Utility Safety Podcast series. Listen now at https://utilitysafety.podbean.com!
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