Connect with us

Need Lightening Protection Experts

Discussion in 'LEDs and Optoelectronics' started by David40, Aug 14, 2009.

Scroll to continue with content
  1. David40

    David40

    4
    0
    Aug 13, 2009
    My home got hit by lightening last Friday and I lost about 7K worth of electronics. I'm trying to determine why it happened and how to protect the equipment in the future. I recently had a Galvalum metal roof put on my house and garage. I thought I would use that to my advantage for lightening protection so I attached some big lugs a various locations and ran large 1/0 copper cables to 8' ground rods. I had already installed various surge protectors on electrical outlet in the house and on the service. Early that evening a storm passed by and just when I thought it was clear, BANG! The TV went off and came back on with just a horizontal white line. I started checking around, and to make long story short, everything that was connected to either the Cable TV / Internet line, the phone line, network cables, or CCTV system was fried. I still have not found the point where the bolt hit but I'm fairly sure it hit the roof. I can't find any burn marks or discoloration anywhere. What I can't understand is why the those heavy ground wires did not direct the entire charge to ground and protect all the electronics?
    I would appreciate it any could direct me to anyone who is an expert in this field or can give me any opinions on what I can do to prevent this from happening again.
    Thanks,
    Sparky! :(
     
  2. amdNRA

    amdNRA

    50
    0
    Sep 3, 2009
    Chances are the lightning bolt may have hit even half a block away but it feels like it just hit your house. The power delivered by lightning is huge. At any rate, it seems like the lightning strike was carried probably by the cable tv/internet into your house. All of these entrance points need to be grounded as well (make sure they are). You could use a power strip designed to clamp down on voltage surges and plug your equipment there. Also, install surge protectors on all the lines that come into the house as well. If practical, disconnect all equipment during a storm. Since normal electrical power surges during a storm, some years ago I built a box with a heavy duty relay and surge protectors that automatically disconnected the power if there was any dropout in the line voltage. It had a button that one pushed to restore power. Basically it all boils down to good grounding techniques and surge suppressors/arresters. Then again, even these measures are no guarantee, as a direct hit will fuse just about everything electronic in the house but at least you'll be grateful you weren't the lightning rod. :D
    Later, Gil. :)
     
  3. David40

    David40

    4
    0
    Aug 13, 2009
    Actually I think it hit pretty close. The tall tree about 12' away from my house is showing signs that it is dying. I think it hit that tree and spread out from there. I would have hoped that my grounded metal roof would act as a shield like the shell of an airplane that get hit all the time without a problem, but apparently not. The woman behind me lost a computer, and the people on the other side of me had all their GFCI's tripped. I appear to be ground zero for the strike. I don't think it was a large bolt because the tree would have been blown to bits if it had been.Guess I'll never know if my metal roof actually attracted the lightening. Since I first wrote I've learned a few things. I did not ground the roof property. They want the rods 24" away from the building and I should have used stand-offs to get the cables out away from the walls. Another thing is to isolate the building grounds from the lightening grounds. I have an old house with ungrounded wiring so I had picked up a ground here and there by running to the nearest water pipe or whatever. I see now that I must run all my building grounds to a single point at the service. Still you are probably correct that nothing will protect against a direct hit.
     
    Last edited: Sep 7, 2009
  4. neon

    neon

    1,325
    0
    Oct 21, 2006
    Must understand this THE SOURCE mils of volts mils of current the ground probably got raised to a couple of 1000 volts acually the house floated with this potential for seconds. solution tie the frame of the house to earth ground with straps so the house will ride with the higher potential and cause minimumn damage.
     
  5. David40

    David40

    4
    0
    Aug 13, 2009
    That sounds interesting but I'm not sure I understand. I have a metal roof but the house itself is all wood frame, so I'm not sure what you mean by grounding the frame of the house. It's an old house so the only original wiring that is grounded is in the kitchen and bath. Any other outlets where I needed a ground I ran a wire to the nearest grounded object like a water pipe. I did ground the roof at four different points with 8' ground rods. Could you clarify?
    Thanks
     
  6. neon

    neon

    1,325
    0
    Oct 21, 2006
    power will seek the lowest PATH to whatever. in your case gnd or earth. so tie a good strap of wire from roof to earth to deep earth like a spike. On the other end it will also atract more strikes to your house remenber lowest PATH. Electrical sub station the gnd is tied to earth gnd for that purposes. your roof sjouln'd conduct that kind of energy so add a very long pole above the roof to provide the path.
     
  7. David40

    David40

    4
    0
    Aug 13, 2009
    Ah, that explains the spikes I see at a nearby power substation. They have these long pointed spikes like tapered flag poles that extend from the ground to about twenty feet in the air, distributed around the equipment.
    Looks like I might have been better off not grounding the roof at all and just added a few of those spikes away from the house?
     
  8. neon

    neon

    1,325
    0
    Oct 21, 2006
    I think you see the light.
     
  9. Pdenny

    Pdenny

    8
    0
    Sep 13, 2009
    Lightning is a strange beast.Based on the amount and type of equiptment, the source was the cable tv.You can add a female inline "F" connector with a grounding screw attachment to the point at which the cable enters the house.Chances are, the cable company may have done this and attachen the ground to a not so grounded point.I saw this on my neighbors house a few years ago.
    I am not a big fan of the cheap surge protectors.Unless you paid more than 150.00 for yours, the cheap units do not have MOVs big enough to suppress the energy from a bolt of lightning.
    Grounding the roof is a great idea and does not mean that lightning will always strike you house.You did well by placing 4 rods at different locations. Most damage from lightning comes from "hit by proxy" (tall trees and power lines) and most direct hits produce housefires and severe damage.
    Over the course of 17 years of consumer repair and have lived in the St Louis area,the damage I have seen has been the results of "hit by proxy" from talking to the owners. One ower told me of the fireball that shot out of the breaker pannel in the basement while she and her familiy road the storm out.
    Good luck
     
Ask a Question
Want to reply to this thread or ask your own question?
You'll need to choose a username for the site, which only take a couple of moments (here). After that, you can post your question and our members will help you out.
Electronics Point Logo
Continue to site
Quote of the day

-