We had a storm to come through my area, though I didn't know it ( sound asleep 3:00 am in the morning). I had 3 calls so far with lightning striking, residences and business'. One house just got a switch plate blown off the wall, and blew a light bulb, tripped some breakers, not so bad. Another business got his computer messed up. I checked all his panels, grounds etc.. Couldn't find anything wrong, except a slightly loose hot wire on the recept. his computer was plugged into. Makes the second time he said his computer has taken a hit. One last year, and now this year. Didn't seem to hurt anything else just his computer. I'm looking to see if Seimans makes a commercial 3 phase surge protector I can put on one of the panels, like Square D does on residential panels. If anyone knows of any, I would appreciate your input. I may just end up getting one of the cheaper lightning arestors that can go on the individual circuit. Supply house told me they cost about $ 50.00 or so. Of course I told him nothing could be guranteed to keep lightning from damaging things. He already has surge protectors etc. ahead of his computer equipment, but didn't seem to help. I had another residential call today from apparantly the same storm. When I went to her house, she proceeded to take me from room to room showing me the damage. Her house has plaster on the walls, with the metal lathe behind it. Somehow the lightning followed the metal lathe and came out numerous places throughout her house. Blew holes in the plaster, smoked up some places around her metal windows, stirred up the "sediment" in her commode, destroyed several mobile phones, cable equipment, door bell transformer, motor in her kitchen hood fan, and more I'm sure, that I'm missing. I checked the service, and found that there was no ground rod or ground wire there at the meter. Looked at the inside panel, which was back to back to the meter, and found the ground wire going into the attic, then back down in the wall of the bathroom ( looked like the wall behind the commode). don't know where it went from there, unless it went under the house to a water pipe, ( hadn't got that far under her house yet). I did have to go under her house to change the transformer for her doorbell, and noticed another ground wire that was attached to the water pipe, that apparantly also originates in the inside panel. I think I did see two ground wires leaving the panel. I am going back to drive her two ground rods at the meter and run the ground wire. I can only assume that the lightning ran along the ground wire, and that the metal lathe was in contact with the ground wire, probably the one going behind the commode and touching water pipes. When I go back, I will try to verify that the water pipes on truly going into the ground and have not been changed over to plastic. I didn't have time to check everything under house, after straining to hook the transformer back up, that was mounted over the gas furnace, in between the water heater and furnace, over a drain line that I was trying not to break; on a cement pad, with about 3 ft. of room, having to work in a "hot box", with a bunch of junk all over the place, and with a barking dog, seemingly wanting to get a hold of me, not to speak of my own "personal" need to get out of there Hope you know what I mean. But other than that, everything went fine Oh I forgot to say about the storage room on the other side of the garage where the panel was, that was "packed" up to the ceiling where the crawl space for the attic was at, that I had to climb over to get up into the attic, ( no way my ladder could have got in there I've told my wife before, that if we could write a book about our experiences in life, that we could sell it and I wouldn't have to be doing these things Oh well, so goes life. Any other theories about the "path that lightning takes"? Thanks, Steve ...If I could only get the time to write that book
[This message has been edited by sparkync (edited 04-14-2005).]
Had a house that didn't get hit by lightning once.
Lightning hit the tree outside their master bedroom.
Their master bathroom had about 70% glass looking outside, the pulse or flash from the tree hit, "spidered" all the mirrors in the bathroom. They had mirrored backsplashes too. Now when I say "spidered" it looked like a spider web in the mirrors, the falsh was so great that it burnt the foil behind the glass of the mirrors, blew out all the GFI's in the house, and took out treadmills, computers tv's and other electronic stuff.
No surge supressors anywhere. Now they do.
Point of the story, lightning doesn't have to directly hit a structure to do damage. The tree was about 10 feet away from the house.
On the guy who got his computer fried twice by lightning, does he have any connection between the computer and phone/cable/DSL lines? If so, I'd suggest checking that these communications lines have proper ground bonding back to the electrical ground system.
If you have two independent ground connections, then a nearby strike can cause current to flow from one ground electrode to the other, though any equipment that is common to both.
I saw an amazing example last year: telephone wire that showed lightning damage between two surface mounted boxes _inside_ a structure. The phone wire came in from a proper lightning arrestor box on the outside of the building, and the arrestor _was_ 'grounded' to a rod. The electrical system of the building had its own _separate_ grounding. There was no lightning damage to the wires outside of the building, nor any damage for several feet inside the building, and then a significant length of burned wire with spikes of copper poking out through the insulation where it had melted and followed the discharge path.
I had a non-hit from a nearby lightning strike once that took out both the amplifier and tweeters of the speakers, even those the entire audio system was unplugged (if I can, I do so during storms just in case since I've witness several incidents in my life of lightning coming in). I guessed the cause of this was due to having "monster cable". But it's not the cable's fault. I originally had the system downstairs and to avoid a shaky front room floor from disturbing the turntable, I put the system in the back room and ran the speaker cables to the front room. I used 75 feet of "monster cable" (was about 6 gauge stranded) to minimize loss and resultant distortion (since speaker impedance varies by frequency, resistive loss in the wire will affect some frequencies more than others). Later when I moved the entire setup to a special listening room upstairs, I didn't want to cut the speaker cable because it cost so much, so I just coiled up the excess in an otherwise empty closet it ran by. I figure that was the bad move as it probably enhanced the effect of the lightning's EM field on the induced voltage. The amplifier power transistors were fried. And the tweaker coils were melted. The crossover, bass speaker, and other electronics survived. It cost about $150 to fix that mistake. It cost another $12 to get some shorter 12 gauge speaker wire to put in place of the "monster cable". Lesson learned.
I went to some of the "search threads" on "lightning strikes" and noticed that it recommended using a good TVSS device at the service and a discharge device at the cable connections, and a quality TVSS at the phone line. Does anyone know of a good web site that has these so I could get a look at them, and other information. Thanks .... Steve
I'm looking to see if Seimans makes a commercial 3 phase surge protector I can put on one of the panels, like Square D does on residential panels. If anyone knows of any, I would appreciate your input.
A series type protector for 200A 208Y/120 circuits. Doesn't just shunt surges to ground, but also contains series inductors to limit letthrough energy at high frequencies.
Substantially more expensive (and more labor to install) than simple MOV modules that fit into the panel, but they seem to work very well. My lab had an ongoing problem with lightning induced surges killing equipment, until several of these units were installed at strategic points in the distribution system.