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Submitted By - Lightning Strike

I am a Line foreman for a utility in Washington state it was a summer evening and we were expecting showers with possibility of thunder and lightning. We took a strike to a double circuit 13.2 kv line getting several calls in the area. One customer called in he and a neighbor were fed off a 3 phase delta bank and there was a irrigation pump off the bank single phase load to the residences. We had one cutout open , we checked the arresters and pots for flash over nothing visible. The cutout door appeared to be melted not blown. We decided to close it in. The door fell open moments later. No bang, just fell open. We inspected the secondary runs and isolated them from the bank. Closed in again, the door fell open. We decided we possible had a bad xfmer, went to the shop to get a new xfmer and installed it. There were 2 Journeymen Lineman in the bucket when they closed in at the end of a short switch stick. Then all hell broke loose, we had a ball of fire that went phase to phase shooting fire out the xfmer vents like a flame thrower showering slag on the linemen and sent the monster galloping down the line doing the Jacobs ladder effect for 2 spans before it broke at a 3 phase gang switch. I have never seen anything like it in my years, no one was hurt, and we still talk about it
today. What was determined after meggarring was that we did originally have a bad pot, but the new xfmer we installed was bad from the factory. We don't test all our xfmers before they go into the field. Needless to say we end up going back in and completely rebuilt the bank that night. The next time your closing in on that new shiny xfmer out of the shop think about the night we got a lemon and lucky that no one was hurt.