A couple days ago I asked about a Lightning Master. When I got back to my post I was a little surprised at the heated discussion that followed. Anyway I read all the posts and there are some distinct opinions out there to say the least. One thing did seem to be in agreement however. Everyone seems to think (for the most part) that the jury is still out on the best course of action. Now I would like to make an observation as simple as it may be. I grew up on a farm in Maine. We had lightning rods on the barn and house. Most of the other old places around us did too. The lightning rods were connected to ground rods with large mesh copper cables. One day we had a real rip snorter of a thunder shower. All of a sudden it sounded like a cannon went off and every one hit the floor. After it was all over there was a big hole in the side of the barn about 35 feet from the nearest lightning rod. All the new houses built around here these days hardly ever have lightning rods on them but they are not hit any more than houses used to get hit. You can get hit by lightning or a meteor. You can be attacked by a rabid animal or a shark. You can get hit by a car walking down the street. A plane could crash into your house right now while you are reading this. The chances of some things happening to you are a little greater than others. But they are all not very common so if you really can’t do to much about it why bother to spend your time worrying about it. While we spend time worrying life passes us by.
- Status
Richard, you are right of course....
after all I have read on the subject, both here and in various sailing mags, I have come to realize that there is no tried and true solution to lightning (maybe a good prayer in a thunderstorm). The best solution I think I will incorporate is a simple set of jumper cables hooked to my stantion and thrown over the side, however, my hope is not to get caught out there (you know how that goes though)...
after all I have read on the subject, both here and in various sailing mags, I have come to realize that there is no tried and true solution to lightning (maybe a good prayer in a thunderstorm). The best solution I think I will incorporate is a simple set of jumper cables hooked to my stantion and thrown over the side, however, my hope is not to get caught out there (you know how that goes though)...
Cars are "Safer"
Experts have always said an automobile is one of the safest places to be during an electrical storm. The metal body of the car works like a Farraday Cage, conducting any lightning energy to ground through the (grounded) tires. In this case, the tires do not act as insulators. There is a potential hazard in taking refuge in a car - ie: gas tank explosion. A secondary charge could ignite fuel fumes in a nearly empty fuel tank. Keep your fuel tank full, and you should be safe(er).
Experts have always said an automobile is one of the safest places to be during an electrical storm. The metal body of the car works like a Farraday Cage, conducting any lightning energy to ground through the (grounded) tires. In this case, the tires do not act as insulators. There is a potential hazard in taking refuge in a car - ie: gas tank explosion. A secondary charge could ignite fuel fumes in a nearly empty fuel tank. Keep your fuel tank full, and you should be safe(er).
Come On Gord
Keep your tank full in order to avoid an explosion in your fuel tank?? This, indeed, may be true, but how many people die each year because they don't keep their fuel tank full? You might be increasing your chances of getting killed. The decision to go into the filling station may subject you to oncoming traffic and the act of filling the station might subject you to a static electricity accident. There are many freakish ways you can get killed. Why don't we armor plate the windshield because of the chance of running into the back of a truck with a two by four sticking out the back? I bet the chances of getting killed are just as great. Why don't we put a big V-shaped guard across the front of the car to deflect everying?
Keep your tank full in order to avoid an explosion in your fuel tank?? This, indeed, may be true, but how many people die each year because they don't keep their fuel tank full? You might be increasing your chances of getting killed. The decision to go into the filling station may subject you to oncoming traffic and the act of filling the station might subject you to a static electricity accident. There are many freakish ways you can get killed. Why don't we armor plate the windshield because of the chance of running into the back of a truck with a two by four sticking out the back? I bet the chances of getting killed are just as great. Why don't we put a big V-shaped guard across the front of the car to deflect everying?
I deserved that, Dan
I was offering additional comment on Fred's statement regarding the safety of cars in lightning. Your point (Dan) is well taken - life is a fatal disease. BTW: Shut your cell phone off, when re-fuelling. Sorry, couldn't resist expounding further (I'm a pedant - it's what I do). Thanks for bringing things back into a realistic perspective, Gord PS:I said PEDANT - not pedarist!!!
I was offering additional comment on Fred's statement regarding the safety of cars in lightning. Your point (Dan) is well taken - life is a fatal disease. BTW: Shut your cell phone off, when re-fuelling. Sorry, couldn't resist expounding further (I'm a pedant - it's what I do). Thanks for bringing things back into a realistic perspective, Gord PS:I said PEDANT - not pedarist!!!
Gord-You are Hopeless
First you apologize and then you negate it by using words I don't understand. By the way, I could not find "pedarist" in my dictionary.
First you apologize and then you negate it by using words I don't understand. By the way, I could not find "pedarist" in my dictionary.
insulators
quote:In this case, the tires do not act as insulators. Tires and fiberglass have a fairly good dielectric value and therefore are insulators and probable account for a great reduction in the hit ratios that cars and fiberglass runabouts enjoy. Certainly however, cars and runabouts get hit. Tire dielectric values will be less when wet skined and the same is true for fiberglass. Plus... dielectrics are subject to laws of physics. Its value must be able to overcome the capacitive charge potentials and if a lightning strike has hit the car and charged its frame to millions of volts, the dielectric properties would almost certainly be inadequate. However, the dielectric properties likely play huge in keeping the car from being hit. Lightning is basically seeking ground, the car on its rubber tires is not at ground potential. Someone standing nearby, a tree, a water tower, a communications tower or a grounded sailboat mast are all at ground potential yet closer to the cloud than the ground. One of the interesting concepts about lightning is that it has traveled so far and so fast that its hard to imagine that it can then be selective about where it hits. This often results in a fatalistic view or temptation to think that the path is just random... and it certainly could at times be so. What we think we know however is that most often the point of discharge is predetermined by the conditions that precede the strike. When the potentials are built, leaders from the cloud draw streamers from ground upward to meet and when the do... the ion trail of the streamer at low resistance provides the pathway and defines where the hit will discharge. The important point here is the streamer starting point. It will be a ground point and most likely an elevated one. This applies to the sailboat in the following way... if the mast is ungrounded... will it supply the streamer? Thomson says yes. That it will draw electric ground potential through the air from the water surface to the base of the mast and raise the ground potential at the top of the mast to that of the water surface. This was his way of explaining why ungrounded mast are hit...that they are both capable of providing a streamer. In reality, I think he was needing to explain why mast that he thought were ungrounded were hit and thus developed that theory. I simply question that most of those "hit mast" that surveyors reported didn't have LPS systems were probably grounded by other means and thus capable of supporting a streamer because they were grounded. I am not saying that an ungrounded mast is incapable of being hit. I am saying that I think a lot of mast have been hit that were thought to be ungrounded but in fact were and the point may be relevant to the strike ratio between the two.
quote:In this case, the tires do not act as insulators. Tires and fiberglass have a fairly good dielectric value and therefore are insulators and probable account for a great reduction in the hit ratios that cars and fiberglass runabouts enjoy. Certainly however, cars and runabouts get hit. Tire dielectric values will be less when wet skined and the same is true for fiberglass. Plus... dielectrics are subject to laws of physics. Its value must be able to overcome the capacitive charge potentials and if a lightning strike has hit the car and charged its frame to millions of volts, the dielectric properties would almost certainly be inadequate. However, the dielectric properties likely play huge in keeping the car from being hit. Lightning is basically seeking ground, the car on its rubber tires is not at ground potential. Someone standing nearby, a tree, a water tower, a communications tower or a grounded sailboat mast are all at ground potential yet closer to the cloud than the ground. One of the interesting concepts about lightning is that it has traveled so far and so fast that its hard to imagine that it can then be selective about where it hits. This often results in a fatalistic view or temptation to think that the path is just random... and it certainly could at times be so. What we think we know however is that most often the point of discharge is predetermined by the conditions that precede the strike. When the potentials are built, leaders from the cloud draw streamers from ground upward to meet and when the do... the ion trail of the streamer at low resistance provides the pathway and defines where the hit will discharge. The important point here is the streamer starting point. It will be a ground point and most likely an elevated one. This applies to the sailboat in the following way... if the mast is ungrounded... will it supply the streamer? Thomson says yes. That it will draw electric ground potential through the air from the water surface to the base of the mast and raise the ground potential at the top of the mast to that of the water surface. This was his way of explaining why ungrounded mast are hit...that they are both capable of providing a streamer. In reality, I think he was needing to explain why mast that he thought were ungrounded were hit and thus developed that theory. I simply question that most of those "hit mast" that surveyors reported didn't have LPS systems were probably grounded by other means and thus capable of supporting a streamer because they were grounded. I am not saying that an ungrounded mast is incapable of being hit. I am saying that I think a lot of mast have been hit that were thought to be ungrounded but in fact were and the point may be relevant to the strike ratio between the two.
Dan & Arlyn
Arlyn: Your position(s) become clearer, and more sustainable, the more you write. I'm beginning to discover increasing areas of agreement, with you. Dan: Sorry ‘bout that (my spelling error). I’m proud to state, that the word is NOT pert of my every day vocabulary. Pederast:: “One that practices anal intercourse especially with a boy.” Momma told me: “Don’t use a big word, when a diminutive expression will suffice.” Gord
Arlyn: Your position(s) become clearer, and more sustainable, the more you write. I'm beginning to discover increasing areas of agreement, with you. Dan: Sorry ‘bout that (my spelling error). I’m proud to state, that the word is NOT pert of my every day vocabulary. Pederast:: “One that practices anal intercourse especially with a boy.” Momma told me: “Don’t use a big word, when a diminutive expression will suffice.”
GordJust hope you have the shortest mast!
Just hope you have the shortest mast in the group during a lightening storm!!!!!!!!!!
Just hope you have the shortest mast in the group during a lightening storm!!!!!!!!!!
Arlyn, the reason cars are safe to be inside
is not because of the rubber tires (as you note), its because you are essentially in a Farraday cage. -- A (mostly in this case) enclosed metal box where as the lightning can travel on the outside and around it. If you had you arm out the window, when your car was struck you would be 'partially' struck - you'd probably survive though. And yes it has happened. Don't think that cars never get struck, they do, and that 6 inches of rubber your tire is keeping your metal car off the road is doing very little. That lightning has travelled miles to find home (ground) you think 6 inches is going to stop it....LOL One other point, mentioned in many threads before, about protecting something during lightning storm (like electronics). If you can take and put it in a farraday cage there is a very good chance it will be fine after the lightning. Wondering how and what the heck am I going to do about a farraday cage, well your microwave oven would tend to be a decent farraday cage, and maybe your oven being another one (depends). Maybe even use a those all metal Propane grill's completely closed. Now I am not suggesting its realistsic to remove every peice of electronics and place it in there, but its something to thing about and maybe be prudent to put a handheld VHF and maybe a handheld GPS in there, because if you struck its a very good chance you'll lose these items and the backup would be a god send.
is not because of the rubber tires (as you note), its because you are essentially in a Farraday cage. -- A (mostly in this case) enclosed metal box where as the lightning can travel on the outside and around it. If you had you arm out the window, when your car was struck you would be 'partially' struck - you'd probably survive though. And yes it has happened. Don't think that cars never get struck, they do, and that 6 inches of rubber your tire is keeping your metal car off the road is doing very little. That lightning has travelled miles to find home (ground) you think 6 inches is going to stop it....LOL One other point, mentioned in many threads before, about protecting something during lightning storm (like electronics). If you can take and put it in a farraday cage there is a very good chance it will be fine after the lightning. Wondering how and what the heck am I going to do about a farraday cage, well your microwave oven would tend to be a decent farraday cage, and maybe your oven being another one (depends). Maybe even use a those all metal Propane grill's completely closed. Now I am not suggesting its realistsic to remove every peice of electronics and place it in there, but its something to thing about and maybe be prudent to put a handheld VHF and maybe a handheld GPS in there, because if you struck its a very good chance you'll lose these items and the backup would be a god send.
Arlyn, I have to respond to your last few
paragraphs. Starting with: "The important point here is the streamer starting point. It will be a ground point and most likely an elevated one. This applies to the sailboat in the following way... if the mast is ungrounded... will it supply the streamer? Thomson says yes. That it will draw electric ground potential through the air from the water surface to the base of the mast and raise the ground potential at the top of the mast to that of the water surface. " I think "true" ungrounded things DO get hit a bit more than you are conceding to. It happens all the time. The question is "What percentage does "true" ungrounded things get struck vs. Grounded or partially grounded" If you question what I proposed, then please explain to me why this guy on this boat got struck and killed. He doesn't appear to be gounded, but if he had an LPS on his boat, he might be alive today. http://www.lowcountrynow.com/stories/082702/LOClightning.shtml
paragraphs. Starting with: "The important point here is the streamer starting point. It will be a ground point and most likely an elevated one. This applies to the sailboat in the following way... if the mast is ungrounded... will it supply the streamer? Thomson says yes. That it will draw electric ground potential through the air from the water surface to the base of the mast and raise the ground potential at the top of the mast to that of the water surface. " I think "true" ungrounded things DO get hit a bit more than you are conceding to. It happens all the time. The question is "What percentage does "true" ungrounded things get struck vs. Grounded or partially grounded" If you question what I proposed, then please explain to me why this guy on this boat got struck and killed. He doesn't appear to be gounded, but if he had an LPS on his boat, he might be alive today. http://www.lowcountrynow.com/stories/082702/LOClightning.shtml
Dan re meaning of "pedarist"
I was unfamiliar with this word to and checked Google and came up with that it means "someone who has sex with underage boys". I suspect it's probably a newer term coined to befit todays modern way of living along with anything goes and nothing is my fault.
I was unfamiliar with this word to and checked Google and came up with that it means "someone who has sex with underage boys". I suspect it's probably a newer term coined to befit todays modern way of living along with anything goes and nothing is my fault.
Cars and lightning
Tom, what you say about car safety and the farraday cage is true, the point that I was making was about the strike the strike ratio of cars compared to tractors and heavy equipment. Heavy equipment that has a roll cage is also fairly safe because of the cage, but they get hit often is my point. btw... Some of you know that I wrote an essay on this subject a year or so ago and gave three credits. The first was to Tom for causing me to become passionate about the subject. So... if I'm excessively windy on this subject... Tom gets part of the heat. The deal with a farraday cage is that the charge is wont to travel the outside surfaces of conductors... and all within the cage is viewed as within the conductor and safe. I wouldn't think this would restrict RF energy which occurs during a strike from penetrating an open cage. To use the capacitor illustration again, when a potential discharges, the DC current momentum of the discharge will oscilate (reverse direction) a few cycles with each cyle greatly reduced in potential. RF is radiated from conduction lengths withing the wavelength of the RF spectrum... These then have the potential to overload sensitive electronic circuitry happening to have tuned circuits within the RF spectrum. A particular trace on a pc board could receive the RF overload and present it to a sensitive chip or component. Your probably right... about sticking the handheld and hand gps in the oven... Caution: Remove before pre-heating oven Not doubting that ungrounded things get hit or that strikes happen without a preceding a streamer. Thoughts on the story. We weren't told what the hull was made of. The report said she was sitting on a wooden seat. Maybe reading too much between the lines, it could be that the boat was aluminum if the writer felt it was important to identify her seat as wood. He very well could have been grounded with a hand on the gunnel or the wheel could have been grounded by steering linkages to the outboard. Here is what I think the deal is... when something is grounded, ground potential is not only raised to the top of that object but because ground is now closer to the cloud leaders reaching down, the voltage level at the top of the object becomes higher than the water surface simply because of influence... just like a magnet, the closer the ground is to the leaders, the higher the voltage is raised. This then presents a disparity between the top of the mans head and the water surface. His hair has a greater voltage level than the water surface... and it might be that hair standing up acts like an air terminal. We've all heard that if we ever feel our hair bristling...to drop prone imediately... that is the reason. I did read an interesting offering about hiking in mountains... the writer suggested something a bit different... to squat on ones toes in order to reduce height and contact surface with the ground. Prone seems pretty appealing to me... if hit, maybe the path out through an arm will save the path through the heart. Does this P- word have any thing to do with our late friend Tristan? Oh, one more story about a Farraday cage. Two of us were on a 375' cable tv tower one day when a rain shower suddenly popped up. We started down (it takes a while) and were slowed even more due to the paint color changes. Red paint oxidizes like crazy and each of those thirty foot sections were very slippery. Lightning struck the tower and was visibly dancing on the guy wires. Neither of us felt a thing. We were like happy but drenched birds sitting on a high line.
Tom, what you say about car safety and the farraday cage is true, the point that I was making was about the strike the strike ratio of cars compared to tractors and heavy equipment. Heavy equipment that has a roll cage is also fairly safe because of the cage, but they get hit often is my point. btw... Some of you know that I wrote an essay on this subject a year or so ago and gave three credits. The first was to Tom for causing me to become passionate about the subject. So... if I'm excessively windy on this subject... Tom gets part of the heat.
The deal with a farraday cage is that the charge is wont to travel the outside surfaces of conductors... and all within the cage is viewed as within the conductor and safe. I wouldn't think this would restrict RF energy which occurs during a strike from penetrating an open cage. To use the capacitor illustration again, when a potential discharges, the DC current momentum of the discharge will oscilate (reverse direction) a few cycles with each cyle greatly reduced in potential. RF is radiated from conduction lengths withing the wavelength of the RF spectrum... These then have the potential to overload sensitive electronic circuitry happening to have tuned circuits within the RF spectrum. A particular trace on a pc board could receive the RF overload and present it to a sensitive chip or component. Your probably right... about sticking the handheld and hand gps in the oven... Caution: Remove before pre-heating oven Not doubting that ungrounded things get hit or that strikes happen without a preceding a streamer. Thoughts on the story. We weren't told what the hull was made of. The report said she was sitting on a wooden seat. Maybe reading too much between the lines, it could be that the boat was aluminum if the writer felt it was important to identify her seat as wood. He very well could have been grounded with a hand on the gunnel or the wheel could have been grounded by steering linkages to the outboard. Here is what I think the deal is... when something is grounded, ground potential is not only raised to the top of that object but because ground is now closer to the cloud leaders reaching down, the voltage level at the top of the object becomes higher than the water surface simply because of influence... just like a magnet, the closer the ground is to the leaders, the higher the voltage is raised. This then presents a disparity between the top of the mans head and the water surface. His hair has a greater voltage level than the water surface... and it might be that hair standing up acts like an air terminal. We've all heard that if we ever feel our hair bristling...to drop prone imediately... that is the reason. I did read an interesting offering about hiking in mountains... the writer suggested something a bit different... to squat on ones toes in order to reduce height and contact surface with the ground. Prone seems pretty appealing to me... if hit, maybe the path out through an arm will save the path through the heart. Does this P- word have any thing to do with our late friend Tristan? Oh, one more story about a Farraday cage. Two of us were on a 375' cable tv tower one day when a rain shower suddenly popped up. We started down (it takes a while) and were slowed even more due to the paint color changes. Red paint oxidizes like crazy and each of those thirty foot sections were very slippery. Lightning struck the tower and was visibly dancing on the guy wires. Neither of us felt a thing. We were like happy but drenched birds sitting on a high line.- Status