I have seen sparks as very green tips of juiciest leaves spark on wires as wind blows , and even can keep a nice straight line across trees as it does. 1x I was subbing a job in a yard with tree row under wires. Home owner tried to talk a worker into cutting simple sapling down. I said NO and so homeowner upset. Yelled down back and forth, pointed out sparking, revised would be cutting into watery layer with metal saw. Also they were my saws and I would choose not to be on site. Advised them free service tho, just need to call electric. Called boss later, he wanted to know why I was talking to his customer....
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A couple of weeks later he calls back customer was upset, nobody called and the row of trees burnt down. Seems him and them wanted to know what I did to cause this, then what I didn't do to include not calling electric company myself. There would be no need to tell anyone else, besides electric to come out and work on his customer's trees. Did not have much to talk to him about after that He even said gave my number to electric, but they never called as I waited to see what was next...
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In some training there was story of guy wires fell on. Taking legs I think, but lived. Another thing tho boiled out his sweat glands. Decade or so back when storms fed into massive summer blackouts, he overheated/bod could not cool self and died the rest of the way then.