lightning is so fast that pure resistive rules do not apply anymore. a long thick conductor to an ideal ground has so much inductance that a large voltage still can develop. that is why blitz protection systems use many grounds to widen the trace using an earth mat approach and minimize the inductance.
a faradaic cage approach usually works easier, by having all systems and persons inside the cage to the same potential,even if that could be several thousands of volts above ground during a lightning.
so ideal grounding is not absolutely necessary, only all grounds inside the cage should be thightly together. phone lines are a source of lightning entering the house. I had my router pulverized by lightning ,plus all downstream ethernet connected electronics.
tip: instead of using expensive 35mm2 copper,I used 3x30mm alu strip as ground interconnects. easy to tap an M8 thread and use M8 A2 SS bolts to connect them.
Alu is less prone to be stolen too. in the crisis the townhall lost 40km of streetligthning wire,dug up by crooks. installing led solar lanterns was the green solution.
a faradaic cage approach usually works easier, by having all systems and persons inside the cage to the same potential,even if that could be several thousands of volts above ground during a lightning.
so ideal grounding is not absolutely necessary, only all grounds inside the cage should be thightly together. phone lines are a source of lightning entering the house. I had my router pulverized by lightning ,plus all downstream ethernet connected electronics.
tip: instead of using expensive 35mm2 copper,I used 3x30mm alu strip as ground interconnects. easy to tap an M8 thread and use M8 A2 SS bolts to connect them.
Alu is less prone to be stolen too. in the crisis the townhall lost 40km of streetligthning wire,dug up by crooks. installing led solar lanterns was the green solution.
I remember when I was about 5 years old and saw a lightning strike in a big oak in the end of a field.
Then there came a ballightning rolling down the field. It was about 2 meters in diameter and speed was as fast as the cars drove, so approximatley 50-60 km/h then.
When it was 30-40 meters away it just dissapeared.
I can remember it very clear even thou it was 40 years ago.
Figge
Then there came a ballightning rolling down the field. It was about 2 meters in diameter and speed was as fast as the cars drove, so approximatley 50-60 km/h then.
When it was 30-40 meters away it just dissapeared.
I can remember it very clear even thou it was 40 years ago.
Figge
whats above the chain? Is it attic space or a second story, a flat roof or a pitched roof? Whats under the floor below the chain?
its the attic , its a complex pitched roof, I will try to see if there is a damage on the asphalt shingles, but I doubt it.
another detail, we modified something to the roof... now it makes more sense..
we installed ridge vents, we are the only one with ridge vents.... one is near the electric wires there... so the lightning could completely bypass the roof sheetings and get easily through that long gap directly to the chandelier ground connection, I guess some of the current could easily jump a few feet near me to bypass the inductive loop of the ground wires (it has to come down to the electrical switch in the middle of the house.
its at the far end of the attic access, so it is unlikely that I can see anything, but I will open the trap and try to see...
everything is underground in the area, overhead wires are 500 meters away, we have to rule out this, this is only related to that chain up there as you well explained.
its the attic , its a complex pitched roof, I will try to see if there is a damage on the asphalt shingles, but I doubt it.
another detail, we modified something to the roof... now it makes more sense..
we installed ridge vents, we are the only one with ridge vents.... one is near the electric wires there... so the lightning could completely bypass the roof sheetings and get easily through that long gap directly to the chandelier ground connection, I guess some of the current could easily jump a few feet near me to bypass the inductive loop of the ground wires (it has to come down to the electrical switch in the middle of the house.
its at the far end of the attic access, so it is unlikely that I can see anything, but I will open the trap and try to see...
everything is underground in the area, overhead wires are 500 meters away, we have to rule out this, this is only related to that chain up there as you well explained.
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My neighbor heard the thunder as never before, the explanation why we didn't hear it is that when the first contact was made we both lost consciousness for that short instant.
The ridge vent would be the modification to the roof (last summer) that gave a straight and easy wet path for the lightning to the top of the chandelier in the attic.
The ridge vent would be the modification to the roof (last summer) that gave a straight and easy wet path for the lightning to the top of the chandelier in the attic.
A common cause of ball lightning getting into houses was a strike on a chimney at the beginning of a storm before the brick work has got wet.
The lightning will find its way down the smoke from the fire and conduct down the soot and throw the fire out of the grate.
Raw coal is no longer commonly used for heating these days.
The lightning will find its way down the smoke from the fire and conduct down the soot and throw the fire out of the grate.
Raw coal is no longer commonly used for heating these days.
Most of this just isn't correct, as kindly put as I can put it.
You might indeed have been a current path.
Essentially the building is not much of a barrier to a lightning discharge, but provides considerably more protection than sitting outside in a storm.
Your theory about how it entered the house is pure conjecture (that's OK) it's also quite possible and likely it never entered the house at all and what you experienced was a shock generated in your house wiring by the large EMP event outside your house.
PRR has touched on the fact as have I that lightning is a high dvdt event, this means that the inductance and resistance of a ground conductor will have a voltage drop across it due to the current flowing through it, if every other ground is referenced to that ground they too will rise to varying degrees. (They can also all have induced voltages on them)
Note that this is true of anything referenced to that or other ground points and can obviously include AC wiring in addition to the safety ground, cable and telco grounds - all of which may be at different potentials during the strike event.
There is no evidence at all that there is anything wrong with the wiring in your house, you just happened to be in the wrong spot at an unfortunate moment.
I doubt you blacked out unless you found yourself on the floor afterwards.
I suggested a solution in my previous post which is to get air terminals (lightning rods) installed on your house.
There isn't much you can do unless you install an air terminal system on your house. I am sympathetic, after two near misses (within 5 meters / 15 feet) of the house I thought about going this route. It makes the strike much safer in the event that it happens, but despite assurances the probability of a strike is not increased I am not sure about that. Two houses in my neighborhood have been struck, one sustained minor damage (exploding chimney and minor fire quickly extinguished by a burst water pipe the lightning used to find ground), the other had a major fire and six months of reconstruction after the insurance settled.
I had lightning damage to some components in my stereo system last summer due to a nearby strike that apparently induced a large common mode voltage in some of the wiring of my house. I have hardened against such events, but there is no protection against a direct strike for anything that is plugged in. (At that moment in time "ground" is a meaningless concept as far as the house wiring is concerned)
Thank you for those inputs.
So before a storm, plug off electronics devices, phones, tv antenna and ethernet makes sense.
And EPM is not like a water wave but follows paths like the ionisated channels in air or some ground conductors according their potential. Better to reduce risks by closing the windows, fire place and being far from doors wheter closed or not?...like saig grand parents.
Despite a close house lightening in the garden or through the air terminal creating an epm, plugged off electronic devives will not receive induced current? Whatever the distance of their non plugged wire from the wall plugs ?
Am I understood you correctly? Lightening fuses at the genral switch interuptor would not suffice?
So before a storm, plug off electronics devices, phones, tv antenna and ethernet makes sense.
And EPM is not like a water wave but follows paths like the ionisated channels in air or some ground conductors according their potential. Better to reduce risks by closing the windows, fire place and being far from doors wheter closed or not?...like saig grand parents.
Despite a close house lightening in the garden or through the air terminal creating an epm, plugged off electronic devives will not receive induced current? Whatever the distance of their non plugged wire from the wall plugs ?
Am I understood you correctly? Lightening fuses at the genral switch interuptor would not suffice?
I note gabdx, that you still assume that lightning entered your house. I'm more in favour of kevinkr's suggestion that it likely never entered your house at all.
Here's some supporting information which I've adapted from the following source: What Is Ground Potential Rise - E&S Grounding Solutions
"Ground Potential Rise (GPR) occurs when large amounts of electricity enter the earth. This is typically caused when lightning strikes occur. When a current of large magnitude enters the earth, the surrounding soil will rise in elecrical potential.
Soil resistivity will allow an electrical potential gradient to occur along the path of the current in the soil. The resulting potential differences will cause currents to flow into any and all nearby grounded conductive bodies, including concrete, pipes, copper wires and people."
I would get rid of that chandelier and chain!
Here's some supporting information which I've adapted from the following source: What Is Ground Potential Rise - E&S Grounding Solutions
"Ground Potential Rise (GPR) occurs when large amounts of electricity enter the earth. This is typically caused when lightning strikes occur. When a current of large magnitude enters the earth, the surrounding soil will rise in elecrical potential.
Soil resistivity will allow an electrical potential gradient to occur along the path of the current in the soil. The resulting potential differences will cause currents to flow into any and all nearby grounded conductive bodies, including concrete, pipes, copper wires and people."
I would get rid of that chandelier and chain!
A set of varistors at the main panel will help except in the case of a direct strike and then there is comparatively little other than luck, where the energy goes is hard to predict, hopefully through a safe path directly to ground and not through your electronics.
Unplugged devices are generally safe from the GPR phenomena Galu mentioned provided they are not connected to anything that is still connected to the mains.
I unplug stuff if I know a bad storm is coming, has arrived if safe to do so and when I go away. I have also invested in a bunch of zero surge brand 120V mains surge suppressors which are effective against most surges but would provide virtually no protection in the event of a direct hit on the house.
Internet is distributed over fast WIFI and the modem is protected by an APC UPS which has a suppressor on the incoming cable. Everything is grounded to house ground and the cable is bonded to the water pipe system in the house. Protection against transients is good, protection against a direct hit isn't and I haven't attempted to harden to that level.
Good idea to plug the router on an APC. I assume for whom having copper phone cable that feed the router from the Internet provider, switching to fiber is a good idea if it's possible in your area.,Or unplug the phone line too I guess !
(My dac is feeded by a NAS which is feeded through ethernet cable from the Internet Provider router... Oups, I will deplug all those devices when storms come !)
(My dac is feeded by a NAS which is feeded through ethernet cable from the Internet Provider router... Oups, I will deplug all those devices when storms come !)
Our internet service comes over coaxial cable to a lightning arrestor (haha, right) then to the APC and finally to the modem/router/wap. The cloud server is connected by ethernet to the modem and is powered by the same APC UPS. Anything the APC can handle should be fine, a direct strike won't be, but at what point do you say enough is enough..
I own all of the hardware and replacing all of it would be under $700 so I no worry..
An added bonus is during a power failure our internet generally stays up. (We don't have many.)
I own all of the hardware and replacing all of it would be under $700 so I no worry..
An added bonus is during a power failure our internet generally stays up. (We don't have many.)
There are reasons that communication antennas are dc-shorted. I disconnected a 80 Mhz GP, before the thunderstorm I thougt, but iduction had already started to load up so when I pulled the plug I got a real beating landing on the floor... Antenna was at 15m hight.
I was well grounded holding one hand to the 19" rack and the plug in the other.
Nowdays I check weather and work with dc-shorted dipoles.
Figge
I was well grounded holding one hand to the 19" rack and the plug in the other.
Nowdays I check weather and work with dc-shorted dipoles.
Figge
Getting rid of the chain may not help in the case of ground rise or a strike to house wiring. in general There is still a pair of wires for the light that will likely follow the strike potential close enough. You would need to get rid of the suspended light.
For residential in the US with a neutral wire, the neutral and ground will be bonded at the panel.
I think grounding the gutters may be a good idea. Having assorted grounded things likely improves you chances of not getting hit.
I actually am happy to have a large power line about 50 feet from the front of my house. Also there a few large trees within 100 feet that also help.
For residential in the US with a neutral wire, the neutral and ground will be bonded at the panel.
I think grounding the gutters may be a good idea. Having assorted grounded things likely improves you chances of not getting hit.
I actually am happy to have a large power line about 50 feet from the front of my house. Also there a few large trees within 100 feet that also help.
HI carter, I will remove (i keep saying it the whole thing, the chain is very heavy and in steel, it supports the thing, the whole thing is heavy.
I checked the house ground before, it is attached to the gaz pipe, it is effective, and conform to code, there is an alternative ground on the water pipe, not connected, I was tempted to connect it too.
Thanks for the idea of grounding the gutters, its an easy job, just a rod, 2 wires, I hope lightning would choose this, or induction whatever
the whole thing, the chain is very heavy and in steel, it supports the thing, the whole thing is heavy. I checked the house ground before, it is attached to the gaz pipe, it is effective, and conform to code, there is an alternative ground on the water pipe, not connected, I was tempted to connect it too.
Thanks for the idea of grounding the gutters, its an easy job, just a rod, 2 wires, I hope lightning would choose this, or induction whatever
Seems like we have two leading but different contenders for explaining the source of the shock. Direct lightning versus induced voltage in the house wiring from the very high field?
Seems the OP was in the path of a discharge that jumped an air gap of some 60cm. If air dielectric is 3MV/m thats about 2,000,000V I guess? Can induced voltages get that high? Im no EE but found two papers that indicated induced voltages in houses without external above ground power lines are under 10kV. That seems to favour the direct lightning theory rather strongly. Furthermore the OP lists home conditions that provide an internal lightning "rod" to just about the table.
We are speculating but the lack of internal house wiring damage and appliance damage argues against induced currents and implies a primary lightning event ?
Brain cells fire off with a potential change of just 25millivolts. Being in the path of maybe 2MV would easily lead to consciousness alternating phenomena. I dont think the OP said he had a generalised seizure or overt loss of consciousness or concussion. Seems he was aware of some phenomena internally generated from induced neuronal depolarisation. That would easily block normal sensory processing like hearing.
This is very interesting and explains why a flash and bang weren't observed.
It would be great to get some CCTV
Looks like your living in a high lightning zone. I wonder why? Could it be underground earthing from metal water main pipes. underground streams or high iron deposits?
Thanks for sharing your tips for prevention of stereo gear damage form lightning.
Is pulling the power plugs out of the wall the best safety tip?
What about induced voltages along lengthy speaker cables?
Electricians having a grade for cabling plants have certainly an strong experience about that like for instance oil, gazoline treatment plants.
Have read somewhere there are different Earth rods qualty, some better than others. The longer and thichier the better, chrome platted copper rod being better, rare and expensive.
But I have no idea if true or not. Maybe worth it in areas like Kevinkr's ...
Are we ok on the fact than an EPM creates more induced current through the soil as explained but also can travel through ionatised air channels, so not a perfect sphere wave like the one created when a stone launched in the water?
In case of guters earthed, current may travel through the soil towards the other main instalation Earth rod? But indeed better than risking fire on the roof?
No ideal situation lightenings are a b...h!
Have read somewhere there are different Earth rods qualty, some better than others. The longer and thichier the better, chrome platted copper rod being better, rare and expensive.
But I have no idea if true or not. Maybe worth it in areas like Kevinkr's ...
Are we ok on the fact than an EPM creates more induced current through the soil as explained but also can travel through ionatised air channels, so not a perfect sphere wave like the one created when a stone launched in the water?
In case of guters earthed, current may travel through the soil towards the other main instalation Earth rod? But indeed better than risking fire on the roof?
No ideal situation lightenings are a b...h!
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