Lightning works in mysterious ways

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goldstar

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New Jersey
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Electrical Contractor
Went to look at some storm & lightning damage yesterday at a friends house. He said he was just about to walk out the front door to mail some letters when lightning hit the tree about 20' in front of his house. It struck the top of the tree, came down the sides in 4 locations in a striated pattern and blew off the bark about 50 feet away. It burrowed a hole in the soil at the base of the tree, traveled under the driveway and hit a sprinkler control wire, traveled into the house, blew a hole in the sprinkler cable, toasted the sprinkler control unit, blew the transformer apart, blew the plug for the sewer ejector motor completely out of the receptacle and toasted the receptacle. There was no other damage.

I told my friend, I know you're feeling unlucky right now but if I were you I'd go out and buy a lottery ticket. A) you're alive to tell the story and B) there wasn't extensive damage.







 
Wow. Did you happen to take photos of the cord and receptacle? Would like to see those as well. It is amazing how it travels, and how some things suffer catastrophic damage, yet others remain unharmed. Thanks for sharing.
 
Wow. Did you happen to take photos of the cord and receptacle? Would like to see those as well. It is amazing how it travels, and how some things suffer catastrophic damage, yet others remain unharmed. Thanks for sharing.
Sorry Sparks, I didn't take a photo of the receptacle. It was in a 4" square box with a Mulberry raised cover. There were char marks around the sides of the receptacle. The back of the receptacle blew apart. The Xfmr for the sprinkler control blew apart and parts were scattered across the utility room. There was a sub-panel about 5' away where the circuit was fed from and the breaker did its job.
 
Looks like it jumped to the copper line rather than the conduit. Might tell him to keep a close watch for water leaks in the near future. Had a strike go to the water system among other things and it actually stressed the solder joints and they began to fail as water pressure surges hit the system.
 
Years ago when I was a contractor in Oklahoma, I was called to a lightning strike at a home.

The lightning hit the upper edge of the roof, came into the house on the cable tv wire (blowing a jagged rip down the wood siding), into the cable box, through the receptacle the cable box was plugged into, and into the panel.

While I was investigating the damage, the lady of the house was trying to make dinner, specifically gravy in a frying pan. She added milk to the pan, and carried the milk back to the refrigerator. When she returned to the pan, the liquid was gone. She repeated the process; same results.

She lifted the pan, and the lightning had come through the electric stove element and blown a quarter size hole through the frying pan.

Unfortunately, this was many years before we all had cameras on our cell phones. For that matter, it was probably 25 years before anyone but the richest folks had cell phones. Because I really wish I had taken pictures.

Lightning can do some really weird stuff.
 
My concern is the hidden damage that can occur when an item is damaged by a lightning surge but doesn't fail but fails at a later date. Using a convenience outlet as an example it a surge breaks down the insulation but not enough to cause a failure at that time and a months down the road the humidity is enough to cause that deteriorated insulation to start to conduct and cause a fire.
 
There was a sub-panel about 5' away where the circuit was fed from and the breaker did its job.

I wouldn't jump to conclusions on that, just because it tripped doesn't mean it did it's job. First of all I don't think it's job has anything to do with lightning protection. Second the small gap in open contacts is nothing for lightning to be able to jump across, or even from the breaker terminal to the panel enclosure or maybe another conductor.

That breaker may not have even tripped because of any current, it could have just tripped from mechanical shock. Most breakers will do this, take a typical plug on breaker just about any brand and tap it on end (especially the output terminal end in most cases) and it will go into the tripped position. Same device that actuates on magnetic trip is what trips it in these cases.
 
I wouldn't jump to conclusions on that, just because it tripped doesn't mean it did it's job. First of all I don't think it's job has anything to do with lightning protection. Second the small gap in open contacts is nothing for lightning to be able to jump across, or even from the breaker terminal to the panel enclosure or maybe another conductor.

That breaker may not have even tripped because of any current, it could have just tripped from mechanical shock. Most breakers will do this, take a typical plug on breaker just about any brand and tap it on end (especially the output terminal end in most cases) and it will go into the tripped position. Same device that actuates on magnetic trip is what trips it in these cases.
Good point. I have to go back there anyway to install surge protectors. I'll open up the breaker panels and check further. I didn't do that initially because there was no damage to the insulation on the wiring when I changed the receptacle.
 
Was doing an inspection one day when I heard, what I thought was a cannon going off, a cannon going off right next to me, made me duck and jump at the same time. It was lighting taking off the top of a palm tree about a half a block down the street.
 
Was doing an inspection one day when I heard, what I thought was a cannon going off, a cannon going off right next to me, made me duck and jump at the same time. It was lighting taking off the top of a palm tree about a half a block down the street.

When I was still a military member we used to train at Ft. Carson CO frequently. Lightning was pretty scary there, and am kind of surprised no one was ever injured or killed by it. Nothing like being out in the open with only shelter being a big conductive mass of aluminum or steel, or a canvas tent, and in early summer you can almost tell the time there by when the daily thundershower starts. I don't recall seeing any trees that looked normal - especially downrange - I think every one of them had been struck by lighting at some time.
 
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