Came across an interesting safety article today and was drawn to the story of Jim White's experience back in the day when he went out to test a 4160 volt transformer that was having problems for a customer. I shared a similar experience with a fellow technician about 10 years ago at a large college university while performing maintenance at night.
Me and this technician were tasked with performing maintenance on 15kv switches at different locations on campus, fed from a substation breaker. We isolated all secondary 480v equipment, installed a lock on the racked out 15 kV breaker, and went to very first 15kv switch to perform work. Keep in mind this was back in the day, before our company had any kind of official safety program.
We took the back cover off and my fellow technician went to install grounds. I said "wait let's test it before we put grounds on." He said "we isolated and lock out everything." I said "yeah I know but let's test babe!" Well to both of our surprise the 15 kV switch was still energized it was being back fed from a Pringle switch on the 480v secondary that was stuck in the closed position after we had opened it!!
After we cleaned the mess out of our pants it took us some time to find the bad secondary switch that was hung up. We found it and the night went on without any more surprises. There was clear Assumption that we were safe!! I like that quote. It's not Dead till you Prove it's Dead!!! Be safe and have a good day.