what is the maximum distant coverd by one lightning arrester?
817738
I think you've mis-stated your question.\n\nLIGHTNING ARRESTOR - A protective device that provides a very low resistance path to any voltage above its rated value. \n\nIn effect, a lightning arrestor will protect the phase of the device wiring *and, subsequently the device itself) immediately downstream (away from the strike). A 3-phase machine will require 3 arrestors, one per phase.
564120
Lightning strikes can travel large distances along wires since wires are made to conduct electricity really well.\n\nTherefore, there is an increased danger to using anything plugged into the wall by cords of any type.  This includes the phone, computer (unless on a wireless laptop), or even the sink (water also conducts electricity quite well along pipes).\n\nNow, the danger isn't extreme.  I can't give you specific numbers, but I do not believe that many people are hurt each year by lightning strikes.  Surge protectors do offer electronics some protection from overload... but can't protect you if a large enough surge comes through the line to fry you.  Generally only very nearby strikes are dangerous.\n\nMy own personal advice: don't worry too much about electrocution from thunderstorms when inside unless the storm is abnormally frequent when it comes to lightning.  It's a choice you make.  Even in a "safe room" you are still in some danger of a direct lightning strike.  Life is short and you should live it.\nHOWEVER, that's my opinion, and playing it safe is never bad.  Each strike is a small gamble... and some people do end up losing.\n\nHere's a bit more info on indoor lightning safety from the National Weather Service:\nhttp://www.lightningsafety.noaa.gov/indoors.htm\n\nI wish you well,\nGod bless,\nShane
280756
My grandfather had one of these.\n\nWARNING: THIS DEVICE WILL PRODUCE A LETHAL ELECTRICAL SHOCK HAZARD, KEEP AWAY AT ALL TIMES. USE AT YOUR OWN RISK. I WILL NOT BE HELD LIABLE FOR DEATH, INJURY OR PROPERTY DAMAGE DUE TO MISUSE.\n\nThis is SOOOOO simple. You will need a steel rod sharp at one end and a plastic handle w/attached single insulated wire at the other. You will have to fabricate this. Wire must be 25 feet long and of 12 or 10 AWG. The rod will be 1.5 feet long.\n\nUsing a polarized plug, connect the single insulated wire to the smaller (HOT) of the plug prongs.\n\nDirections for use:\n\nAn area of about 10 feet from rod WILL PRODUCE A LETHAL ELECTRICAL SHOCK HAZARD, KEEP AWAY AT ALL TIMES. USE AT YOUR OWN RISK. UNPLUG THE DEVICE BEFORE APPROACHING IT.\n\nThe ground must be somewhat moist (not wet), best results are in the shade or cloudy day.\n\nFirmly push the rod into the ground at least 20 ft away from any building.\n\nPlug in the polarized plug into a socket for no more than 5-10 minutes at a time (this depends on ground moisture).\n\nAn area of about 10 feet from rod will produce worms in the time specified, if not, try a different location.\n\nClean and oil rod after every use to prevent rust. AVOID GETTING OIL ON THE HANDLE AS OIL IS CONDUCTIVE.
909147
The only situation there is for placing a trap at the far end of an antenna, is if that antenna is part of a multi-band antenna system. For instance, you could put a trap at the end of a 1/4 wave 20m antenna (at about 16 ft), then connect the other side of it to an additional element, for 40m or 80m use.  If the antenna is for 160m, the only reason to have an extension is for BCB or LW coverage.  Is that what you're up to?  By the way, as already mentioned, the trap has to be used at a current peak (voltage node).
1062318
Perhaps the link will help.  At a minimum, you risk voiding your warrant if you use other that the voltage and frequency required on the unit name plates.  At worse you risk injury and a possible fire if you really don't know what you are doing.  Good luck.
125595
Leaving them turned off still won't help, because a lightning strike could still fry them. \n\nYou need them well grounded and in a Faraday cage if you want to avoid ALL pulses, including from lightning strikes.
1187416
false sound moves at 331 m/s or about .20miles / second so 7 seconds between sound and lightning is about 1.4 miles away
934779
Hi Ma...The answer may vary State to State/Privince etc..Even different Municipalities and Cities have their own rules...\n\nThe easiest way is to contact your local City planning dept...\nYou can't go wrong there....Generally the farther away from power poles, the better it is for safetys' sake...\n\nGood luck and please be careful... :)
1076337
Maximum travel distance can never exceed 75 feet in any situation. However, that doesn't mean the fire extinguihsers get to be every 150 feet! It's based on multiple factors:\n\nThe hazard class of the occupancy plays a big role (i.e. a factory that processes paper products is going to be a higher hazard than say a factory that produces metal parts.) These classes are broken down to Light (low hazard), Ordinary (Moderate), or Extra (High) Hazard occupancies.\n\nThe next thing we have to look at is the classification of the extinguisher you are using. It will have a UL rating, something like 4A:60B:C. The number of A units is multiplied by a square footage factor that is based on the occupancy we just talked about.\n\nThe maximum amount of square footage the extinguisher can cover, per units of A in its rating, is 3000, 1500, and 1000 respectively with the lowest square footage being for the high hazard group. Also no extinguisher can ever be allowed to cover more than 11,250 square feet.\n\nLet's run an example...\n\nLet's assume your factory is a moderate hazard and you are ordering 10Lb. ABC Multipurpose fire extinguishers to cover it with a rating of 4A:60B:C. Then each unit can cover roughly 6000 sq.ft. of floor space with travel distances never exceeding 75 feet. \n\nDivide the factory up into 6000 sq.ft. "sections" where each section gets 1 fire extinguisher located somewhere inside that section. Place them where they will be safe from impact, can be seen, will not be blocked, and on paths to an exit whenever possible. Insure travel distance does not exceed 75 feet to any unit from any point in the facility and that's NOT necessarrily measured in a straight line, but along the path someone might have to take to get around equipment and what not. \n\nFinally, you must also be aware that there are specific pieces of equipement that may also need a fire extinguisher of a particular type located within even closer distances, such a flammable dip tanks, industrial tow motor recharging areas, flammable storage areas, etc., etc.\n\nNFPA 10 is the National Standard on placement of fire extinguishers. Almost every state in the nation adopts it as code. This guide has really good illustrations and discussed various examples to handle almost every conceiveable layout. I highly recommend getting a copy and referring to it.\n\nAlso, involve your local fire prevention officer (or fire marshal) and/or your insurance company. They may have additional items for you to consider and they will probably be more than willing to help.
211344
Its in Wikipedia, the free encyclopedia, just type the "Faraday cage" in yahoo search you will find the 75% for your answer and rest you do your home work.
108122
http://science.howstuffworks.com/lightning.htm
27336
In addition, you will have to raise the transceivers above the obstructions.  These signals are notorious for being "line of sight", and are easily obstructed.\n\nThe easiest way is to get a mast and mount it on the roof.  If that is not possible, look for a HAM radio antenna tower.  You can stack them as high as you need in order to get above the obstructions.\n\nIt does not take much to block these signals.  Even rain can prevent them from going through.  Ask anybody who uses DirecTV or Dish Network about that.
923031
very, i lost everything in my computer once because of lightning. if you're sure to unplug your computer whenever theres a storm coming, you should be alright
918837
In theory there is no upper bound except those imposed by real-world engineering constraints.\n\nThe Russians popped an underground event in Siberia that was a bit over 50 megatons.  It *moved* the entire  Siberian techtonic plate something like a centimeter and they decided that was probably as big as they needed to test ☺\n\nSay you detonated something in the 10 megaton range at an altitude of about 5 miles.  Pretty much everything within about a 3 mile radius of 'ground zero' is going to be, literally, vaporized.  In fact, the top 30 or 40 feet of ground zero is going to be vaporized, leaving a sort of round 'dish' shaped depression a mile or so across in the ground.  Inside this radius, the 'dish' will be coated with a 'slag' formed as melted soil and rock cools.  Depending on the minerals in the area, some of these slags are quite colerful and would make excellent souvenirs.  (Just avoid the ones that glow in the dark ☺)  Everything out to about 10 miles or so will be knocked flat and/or incinerated (total destruction on the surface) by the heat and shock wave.  The structural damage begins to fall off after that, but significant damage to structures would still occur at ranges of 20 or more miles.  People directly exposed to the event would be killed (instantly) by the radiation at distances of up to about 10 miles.  After that, survival probabilities would increase logarithmically out to about 30 to 35 miles.  Life expectency (which would be zero out to ranges up to about 10 miles)  would go up along a logarithmic curve out to a range of about 100 miles or so, at which point the mean expected lifetime (post event) would be about the same as it was before the event.  One exception would be optical effects.  Anyone looking in the general direction of the event would probably be blinded out to a range of 30 to 40 miles.\n\n\nDoug
774921
What they do is that they run along the field with a conducter connected to voltage meter.  Lol.  Just kidding.  They set up "antenna like " conducters in a field that is most frequently hit by lightning, and all of these conducters are connected  to voltage meter.
1182365
Using your 800 miles per hour, we can reduce that to 0.22 miles per second.\n\nThis works out to approximately 1 mile per 5 seconds.  This explains the two previous answers which are correct.\n\nSimply count the seconds from when you see the lightning until you hear the thunder.  Then divide that count by 5, and thats how many miles away from the lightning you are (approximately).\n\nThe speed of sound varies considerable because of temperature and wind.  And, your count isn't that accurate either, but its good enough for an approximation.
283845
Clearing a few things up:\nlightning can go from cloud to ground, ground to cloud, or cloud to cloud.\nThe charge buildup that causes the lightning is focused in the cloud and on the ground.  But the lightning doesn't go from one to the other and just stop.  The difference in charge becomes large enough to cause a "jump" between the air and ground (or whatever the source/target).  This is like an arc in an electrical current... the voltage builds up to a point where the inhibition of the atmosphere (or wire covering) aren't enough to contain it, cuasing the ions to jump from the one place to the other.  As an aside, lightning is caused by opposite charges building up.  Typical lightning is negative (negative charge flowing to positive charge).  Less common is positive lightning, which is much more powerful/damaging.  The -/+ ions flow to the opposite charge.  Lightning starts wth a stepped leader of particles "reaching out" from the source AND target until a path of low enough resistance is found at which time the lightning strikes.  The path is set and large amounts of ions flow along the path until the charge difference/voltage decreases to a point at which the resistance restrains the flow again.\nThe lightning doesn't stop at the ground when coming from the cloud... it keeps spreading out until the charge difference is neutralized/the energy dissipated.  This can lead to lightning ions travelling large distances into the ground (or along underground phone lines and such).\n\nTired of me talking?  Looking for a point?\nThe point is that you can be hit in the sky!  Partciles of air aren't directly grounded either, but the lightning goes through them.  Humans are less resistant than air (that's why being the tallest object in a thunderstorm is dangerous), so in theory you are the easier path.  And just because you aren't grounded doesn't mean you don't get burned as the lightning passes through you (just as it would if you were grounded).\n\nDoubt the danger is rediculously extreme, but its a threat.