The same thing happened to me. I was lucky. In my first year of apprenticeship here, we had a problem with a manual three phase circuit breaker. It was for our concrete mixing plant. I thin the fuses were about 800 Amp. The CB was loose, and a connection had gotten hot, melted the plastic and was not making good connection. My Meister, (Master Electrician) Was a young buck. He had worked for the power company, and gone from there to the large company where I was apprenticed. We needed to change the CB, and he did not want to shut off power to half the town of Weismain, to do it. He would have to shut off the power to the company HQ, and the Big Bosses house. So he brought in some insulated tools, and said "We would change the CB under power." We meant me. No one else wanted to do it, as they knew and UNDERSTOOD, what was going on here. And I had never turned down a job. Working on a crane, 60 meters tall or higher? Working on the side of a building, 40-50 meters high? Working on indoor cranes, walking around 30-meters above the plant? No problem. Guy was always ready. Scared? You bet. But if the Meister was with me, well, if he would, I would. I pulled the CB down, took out the fuses. Then we went to the back side of the transformer house, and He gave me the ratchet, and told me to loosen the attaching bolts/nuts and the he would take the CB out of its frame, put the new one in, and I would tighten it back up, with the insulated ratchet. No safety gear other then then rubber gloves and insulated tools. The part of my schooling that would have educated me to how wrong this all was, came in the second year of the course. When everyone moved away from me, or flat out walked out, it began to dawn on me. I started to sweat like a pig on the way to the butcher's. I took it slow, and everything went as planned. I tightened the last bolt/nut, on the CB, and was pulling the ratchet and extension out of the back side of the CB. Now, the socket, was the only part of the gear NOT insulated. I almost had it clear of everything, when the socket hung on something, and fell off the extension. I watched it bounce on the L1 rail. The rail was 4 inches wide, 1.5 inch thick and 2-3 meters long. It hit the rail, and fell down in between the L2 and L3 rails. If you have never seen an electric arc, of this magnitude, there is no real way to describe it. Its a thing of beauty. So bright, so clear, so intense, that only maybe a nuke burst would top it. But the most scary thing is the sound. Its like nothing you should ever hear in your life. It sounds like a child who has screamed because his legs have just been crushed, or maybe had his hand ripped off. A sound to chill your bones. The vaporized metal dust, (Plasma) hit me in the face and upper chest. The only thing that saved my eyes is that I wear thick glasses, and have always liked big wide lenses. Of course I had a killer sunburn. And my skin felt like sand paper. Oh, yeah, I was blind. All I could see, with eyes open or closed, was an Incredible Orange Red. Just that. I froze in place, as I still had the ratchet and extension in my hands. The only thing going through my head was DO NOT MOVE. The silence was Incredible. The Meister said, "Guy, are you all right?" I said, "Jürgen, when I can see, I am going to fu****g kill you." He left. My mentor came in, eased me back, and guided me outside. I sat down. Pants wet. I waited a long time. The first respondier's showed up and took me away. Did nice things to me and my eyes. My glasses could have been used to file steel bars. I could not see well until the next day, and my eyes hurt a while. Every time I have gone into a transformer/sub station since then, and it took a long time before I could, the whole stupid episode plays in my head, and not just once.