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felonious smile.
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We have installed GFI receoptacle and breakers on behest of a customer last year who insisted they would prevent harmful surges. I gladly took his money at the time. He called the otherday to thank me for ajob welldone. His house had got hit by lightning and nothing electrical toasted, every GFI tripped, one needed to be replaced. I originally entered this situation with extreme skeptism, I think I'm sold now. Are GFI's a proven surge protector?
 

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Anything can happen in a lightning event, I guess. It problably would depend on where the strike hit the house...at the service, or the aluminum siding. or somewhere through wood. If it hit wood the water in it would explode and you could see the damage. If it hit the service head and set up a lot of eddys in the conductors on its way to earth I suppose a GFI could react that fast.
 

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Ax grinder
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A GFCI provides no surge protection.......... the surge of a lightning strike would jump across the fried components and continue to the item plugged into the outlet.
Agreed.

GFCI protection does not protect against surges or lightning.

A GFCI device monitors the current on the ungrounded and grounded conductors of the circuit. If there is more than 4 to 6 milliamps of diffenernce (Leakage current) then the GFCI device will trip.

Chris
 

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I live in Tampa, Florida--- The lightning capital. I have seen many items fried that were plugged into GFCI outlets and on GFCI circuits.
There are approximately 6000 lightning strikes per minute around the world. And you are right. I was talking theoretically, anyway. The poster's experience suggested they may have usefullness, your's suggested not. Who knows in a trade full of theories:thumbsup:
 

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Fried Bologna um um good!
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There are approximately 6000 lightning strikes per minute around the world. And you are right. I was talking theoretically, anyway. The poster's experience suggested they may have usefullness, your's suggested not. Who knows in a trade full of theories:thumbsup:
It's not theory really. It's mother nature. Too many factors determine what gets hit and where it goes when it does. Ive seen some things on a circuit hit that survive and other things on the same circuit die.
 

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This isn't quite the same as a lightning strike, but it still created a surge throughout the system. A couple of fighting seagulls managed to become shorting probes to ground at a pole mounted residential transformer and the resulting blast and feather cloud surged 4 homes served and although the gfci's were tripped, everthing electronic attached in some way to the electrical system fried with them.
 

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felonious smile.
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Discussion Starter #10
I'm still skeptical, however the HO is not. Would I sell them for that purpose? NO. If asked if I can install them for that use? Yes. Supposedly the strike did not hit the structure but landed several feet away.
 

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I'm still skeptical, however the HO is not. Would I sell them for that purpose? NO. If asked if I can install them for that use? Yes. Supposedly the strike did not hit the structure but landed several feet away.
That is the whole deal. The vast majority of strikes are near miss events. If someone asks you to install them for that purpose, again, at least you have some experience with it, but I wouldn't voluntarily tout it as such...or turn the job down.
 

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Ax grinder
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The fact that all the GFCI's tripped is most likely a result of the lightning strike and the fact that they tripped does not indicate that they protected anything from the lightning strike.

Chris
 

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Supposedly the strike did not hit the structure but landed several feet away.
That's the part that jumps out at me.

I've heard of cases where GFCI's tripped when people near them transmitted on a walkie-talkie. So apparently they're unusually sensitive to strong electromagnetic fields. What accompanies a close lighting strike but a big EM field? It might not have had anything at all to do with any voltage surge on the house circuits. Especially considering that the lightning didn't even directly strike anything attached to the house. I'm not an physicist, but I did stay at a Holiday Inn last night.

If asked if I can install them for that use? Yes.
Hell, I'll do anything they want if they write it on the back of a big enough check. I'd even wrap all their devices in red tape, if someone where stupid enough to request it. :whistling2:

-John
 

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Electronic equipment is most often damaged by a surge sending current to the ground connector and this is their Achilles' heal. Not at all unusual to have voltage on the ground at a wall outlet and easy to check.

In Florida or Texas a whole house surge suppressor is a more economical solution. In most areas the problem is one of low voltage sags and line conditioners are needed to protect expensive electronics.
 

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Agreed.

GFCI protection does not protect against surges or lightning.

A GFCI device monitors the current on the ungrounded and grounded conductors of the circuit. If there is more than 4 to 6 milliamps of diffenernce (Leakage current) then the GFCI device will trip.

Chris
Agreed.

GFCI protection does not protect against surges or lightning.

A GFCI device monitors the current on the ungrounded and grounded conductors of the circuit. If there is more than 4 to 6 milliamps of diffenernce (Leakage current) then the GFCI device will trip.

Chris
NEC 2020 code is requiring the AC disconnect for an HVAC system be wired to a GFI breaker back at the panel. If you install a surge protector at the AC disconnect, like millions already have, will the voltage a surge protector dumps to ground trip the GFI breaker back at the panel?
 
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