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How to Protect a Network Against Lightning?
RichiH asks: "The monsoon, started about a month early in India this year. While it is not sure if that is due to global warming or not, there are more pressing issues for the IT world at hand. Until about the end of July, there will be major thunderstorms in this area. How do you protect a network that is spread over 100 square kilometres in a land where the concept of a lightening arrestor is next to unknown? The network in question consists of about 2500 boxes of various kinds which are connected using 10BASE2 (aka BNC), 10BASE-T (aka RJ45) and 10BASE5 (aka thicknet), where only the last one may be new to some readers. The big question is: how can you protect yourself against these storms in a way that is both fast to implement and does not require laying of new lines?"
Two words, lightning rod.
During monsoon season, outsource your IT operations to the United States.
-- We live in a world where lemonade is artificial and soap has real lemon.
Preferably Florida, they know lightning there.
;)
Sure your bandwidth is lower (in general), but you can't induce a current along a 2.5GHz wireless link...
--
"we live in a post-ideological world..." - Billy Bragg.
U P S
You're in India, you say?
Actually, the safest way to protect your equipment against lightning strikes is wire a lightning rod directly into your network's central switch. The extra voltage and current from the lighting will safely disperse through all the attached systems, and you may even notice an increase in performance!
Don't let anyone tell you otherwise.
This space intentionally left blank.
euh... shouldn't you have thought of that before?
Like, you know, at the time of installing the network?
just asking, what do I know about stuff like this...
There is just not enough detail in your post to give any more specific advise. But a quick way to isolate one segment of the network from another would be with a pair of wireless bridges (i.e. 802.11 "access points"). Maybe outside your budget, but they can be had for $100 each. Just make sure they have a bridging mode.
" The big question is: how can you protect yourself against these storms in a way that is both fast to implement and does not require laying of new lines?"
802.11 + a Pringles can!
"Derp de derp."
How to pray
A few years ago my friend and I decided to set up a network between our houses. We ran about 200 feet of 10BASE2 along a fence and used an old 486 DX33 box on each end as transparent bridges between the cable and out LAN segments. Every once in a while we'd get a close lightning strike in the summer and it would fry one of the combo cards we used. Fortunately, they were old Linksys NE2000 compatable ISA cards I picked up used for about $2 each. I'd go through about 1 or 2 every year. I tried using a spark gap type arrestor, but it wasn't enough, besides a few bucks a year was worth it.
IIRC Protection from Lightning is a 4th level Cleric spell!
Geeks these days...
I watched C-beams glitter in the dark near the Tannhauser gate.
"How to protect your electronic devices against lightnings. A research paper by Angus Ingrid, University of Technology Berlin".
Here is an extract from the concluding part:
"After carefull research we are now convinced that the solution to the problem was: roof."
Prevention (of a lightning strike) is impossible, or at least too expensive to ...) that it destroys whenever it hits. For starters, you need to split
be practical. What you want is to minimize the amount of stuff (equipment,
data,
your network into segements in such a way that data can travel between the
segments but lightning won't. Wireless is one option, but I think there are
other ways to accomplish this. Some UPSes have data line protection...
Then there's data. One word: backups.
Cut that out, or I will ship you to Norilsk in a box.
People have suggested wireless, but another option that isn't an issue for power surges is fiber optic connections. You probably won't run them to each computer, but with some strategic placement, you can at least electronically isolate different portions of the network.
That's a good idea regardless of lightning, simply because ground isn't quite the same from building to building. (Or sometimes even from outlet to outlet.)
You're looking for something called a "lightning arrestor", and Google will turn up several links for that.
.5 meters apart (two rods at the end of each grounding path), then run wires from that to the grounding screw that's on the chassis of most computer equipment. If the computer has a 3-prong plug, and one of them is a ground, then you can just use the grounding system of the electrical system. Sometimes you can substitute the piping in the building for the copper rods driven in to the earth, but it's not as sure a method as using a real grounding system. A qualified electrician should be able to help you out.
Basically, you drive a bunch of 2-meter copper rods in to the earth at various places, at least
But the thing everyone forgets is that they only do the power connections. ANY wire is a possible conduit for a lightning strike. You need something like this http://www.ba-electronics.com/a28.htm on your network runs. Some people use fiber instead of copper as a method for breaking the path.
Overall, you want to get the lightning from where it hits the building (lightning rods) to conduct down an exterior path of wires to a grounding system. Should any stray voltage get in to the electrical system, or jump to telecommunications equipment (you did remember to ground the phone lines, right?), you want another grounding path to direct that extra voltage away.
There's also something I saw once that the electrician called a "lightning bottle". It was a single coil-like item that was placed inside the main circuit box, and diverted high-voltage connections to ground. I don't know if that was the slang version of the name, or the real name. Someone else here might be able to help.
Lighting is powerful stuff, it can travel through miles of air, which has a resistance that's probably in the teraohms. There's not much you can ever do in the event of a direct hit. But you can minimize the damage caused by lesser nearby strikes by using surge protected patch panels. Make sure they're connected to a good low resistance earth ground. I've seen them often in networking catalogs. Things like NICs and hubs will often act as a fuseable link, opening up or shorting to ground and preventing the damage from spreading very far.
As a said, in a direct strike, you're pretty much screwed no matter what. Indirect strikes can induce very high voltages, since they give off a pretty good EMP. It's extra-important to surge-protect the long runs of cable. You don't need to lay new cable, just install surge protectors at both ends of the run.
Buy cheap networking equipment, and keep money to replace it on hand.
-73, de n1ywb
www.n1ywb.com
...we're in the middle of a gigantic snowstorm. With thundersnow, yet, which is kind of unusual. I heard the forecast and thought "Hmmm, OK, a few flakes maybe!" (it was something like 24 C yesterday). Today? 10 cm of snow followed by a predicted 10mm of rain tonight, more of the same tomorrow. Looking outside my office window, I'm thinking we've had more than 10 cm already. It's been coming down so thick that driving visibility is severely curtailed.
Still, it's kind of neat to have one of these storms in May. Although if one more person comes into the office singing "It's Beginning To Look A Lot Like Christmas" I'm going to jam the "Department of Redundancy Department" sign down their throat.
Cheers!
Corruptissima re publica plurimae leges.
The amateur radio folks deal with lightning all the time, and they can be a great resource. I'd suggest http://www.arrl.org/ as a starting point.
Who moderated this informative? The individual is trying to be funny. As for the question. There's two ways, Containment, and isolation. Someone suggested wireless links. That will break some of the paths, but not others. The other is containment. Minimize the number of paths that lightening or a power surge can take. For example a whole house surge protector instead of a whole lot of little ones. A big surge protector at the demarcation point for the phone lines instead of a lot of smaller ones. There is one thing you do have to watch out for and that's long wire runs, be it power, or ethernet. Put inductors around the power lines, and minimize the runs. And yes I recommend a lightening rod as a part of containment. They aren't expensive, and an individual can easily install them. And last make certain you have a backup plan when something gets through, because it will sooner or later, despite your best efforts.
Take a look at APC's rackmount "ProtectNet" stuff.
A 1U rack mount chassis with 24 slots (you can protect up to 16 data lines) is $30. Then you can buy different plug-in modules for different devices. They have them for 10/100BaseT, regular Telco phone lines, T1/ISDN/etc, RS232, etc.
Get one of these for $18 per Cat5 you want to protect.
Keep in mind that nothing is going to protect against a direct lightning strike, but these are good filters for surges that can come from an indirect hit.
Actually I did forget one more (silly me). Make certain you have a good ground over your entire electrical system (no ground loops). Check and make certain there's no corrosion at the clamp point with the ground rod (there are coatings you can use). Make certain the equipment is in good working order.
Fault detectors (GFCI) will help as well, but don't become overly reliant on them.
I know a lot of Slashdot readers are pretty young, but wow... 10BASE5 (thicknet) being new or unheard of... makes me feel OLD (and I'm only 30!)
ahh yes my friend you see it very simple really when you think about it. you could outsource to somewhere like Florida or Boston.
/. what's next on this goddamn forum?
come on
"excuse me but we in bangladesh were wondering if you could ever so kindly sho us how to do a hip replacement?
THE best way to avoid equipment damage during a lightning storm is to unplug your equipment. From mains and network. If your mains is lightning-safe, you could leave that on. Getting that many people to unplug units is practically an impossibility, I know, but crucial network nodes could be unplugged at the highest risk times. Factoring in some redundancy could be a good idea so if one router gets smoked, there is another somewhere else (geographically) to lower the odds of a complete system down.
But he eventually bought a locally made UPS. He said it was noisy, making hissing and spitting noises. But it worked great.
Well, that was twenty years ago.
In urban areas at least, is the Indian electrical grid now able to provide clean power? I am guessing it can. Maybe your local geeks can provide you with better advice than slashdot?
Just pile human bodies over top of all the physical lines. They attract lightning and absorb all the damage. Besides, if Indians are willing to work under inhumane conditions in call centers for pennies an hour, they'd probably be willing to do this for a few cents more, right?
Moderator hint: a comment is neither "Flamebait" nor "Troll" if it is true.
You can get arrestors for 10base2 and 10base5. These should be installed on every building, near the electrical service panel (entrance) and tied to the building electrical ground stake. I think you still have those with ring-mains. Use as short and as fat a wire as possible -- impedence matters.
10baseT and 100baseTX should never be run inter-building and arrestors for it are hard to find. Beware the cute little cubes in userspace -- they have a long ground return path which presents high impedence, forcing more of the surge through active components.
Make sure all your computers have three-prong plugs.
How about using a copper-fiber ethernet bridge at the points where you want to isolate? I suppose the cost might be problematic, but it shouldn't be terribly difficult to find.
Fiber.... Get a two fiber to 10baseT, 10Base5, 10Basew2, 100BaseT or 1000BaseT transeivers. Lightining doesn't really impact fiber. Then use fiber for the long haul...
OR
you can buy 4 Fiber transeivers and a two, 1 meter fiber patch cords and put 2 transeivers on either end and use it kind of like a optical isolator. then if lightining hits the transport copper you, at most lose 2 transeivers, and the networks on either end are ok. Then all you should have to do is replace the 2 transeivers on either end.
--Ted
--Hired Net Grunt
Let's kill two birds with one stone.
AC (Alternating Current) isn't the same thing as RF (Radio Frequency). Two the levels are so low that it's effectively irrelivent. Now if the RF energy was ionizing the air, you might have a path, but even TV stations don't do that.
Poster two
"All except for that great big metal and plastic rod sticking up that we call an antenna..."
Not all antennas "stick up", and there are ways to minamize the effects of "sticking up". Remember lightening rods, and antennas work because of the point at the end, not the fact that they're rods.
poster three
"Okay, correct me if I'm wrong, but this sounds like a horrible solution. Haven't you ever seen your tv blip or heard your radio go staticy during lightning? Lightning acts like a very large spark-gap transmitter. As we all know, spark-gap transmitters throw out nasty RF over several freqencies, and I don't think they discriminate against 2.5GHz."
One problem with your statement. Most natural phenomenon doesn't broadcast in the Gigahertz range. Two there are ways of dealing with unintentional interference (lightening or otherwise).
Whenever there is a lightning storm get some employees (aim for the expendable ones), to run around the outside of the building while carrying metal baseball bats, lengths of pipe, or wearing tinfoil body suits. I save thousands with this method and also avoind paying out those pesky unemployment benefits!
"Remember lightening rods, and antennas work because of the point at the end, not the fact that they're rods."
Actually I'd better clarify that before someone jumps on me abou it. The way lightening rods work is by providing a lower path of resistance. Remember during a lightening storm there's two pools of charges. The cloud, and the earth, of opposite charge with a high dielectric between them. Trees and lightening rods bring the iwo together and concentrate it (much as a pin concentrates force on a baloon surface). Now if I had a rod antenna with a big ball on the end, it'll work, but not nearly as well as something with a sharp point.
You do realize that what you got hit by could have been caused by induction, and not any kind of plasma transferance?
You will be happy to know that I just called my favorite tech support line and spoke to someone in India. I had trouble understanding everything he said, but I did catch his name: "Jimmy."
Jimmy worked with me for about 30 minutes on the question of protecting computers from lightning and then passed the call on to his supervisor, "Susan", who also had a very thick accent. According to what I was told by Susan and Jimmy, all one has to do in the case of a lightning strike is type about 40 commands starting with "ipconfig" and ending with "path." If there is no response to any of the commands, the answer is to unplug the computer, wait two minutes, and then plug it back in again.
Surprisingly, that's the same answer I've received from them for everything from a dead cable modem connection to RAM parity errors...
Then they start to scratch their heads when they realise that they can't protect their networks from the natural weather and decide to ask slashdot.
Dumbasses.
You can hope the lightning won't strike, but beyond that any commercial lightning protection available will not save any electronic equipment from a lightning strike. Lightning is just way too fast for the electronics in the circuit to respond... litterally the electronics get burned before it can even think about overcurrent. Maybe, if you are really, really lucky, just your power supplies burn out.
Every PC, every switch, every printer, every server.
We installed 3 printers, 6 PC's, and 1 server at a client. The next day, the pole outside got hit by lighting. The electricty burned the CAT 5 in the walls and smoked all the PC's and printers. The server survived, all it needed was a new NIC.
Insurance paid us to do the job all over again...
Two words, lightning rod.
Actually, among people who care about these sorts of things [and there are precious few in this business who give a damn], lightning rods, and, more generally, good grounding, are enormously controversial.
Classically, the thinking was that a well grounded lightning rod served to divert voltage surges away from the interior of your structure and down to the groundwater, or, more specifically, to the ionized particles suspended in moist soil. [Oh, and, by the way, once the surge makes it to "groundwater," there's no guarantee it'll stay there; it's entirely possible that it'll decide it doesn't like groundwater and find an alternate route back into your structure. These phenomena generally fall under the title of "grounding loops."]
However, there's a new school of thought which holds that a well-grounded lightning rod serves to ATTRACT voltage surges, and could cause a voltage surge to get nearer to your structure than would otherwise be the case. If you follow that approach, you want safety in numbers: You hope that there are enough targets out there that are well enough grounded that the voltage surge will be diverted towards them, rather than towards you.
If you're interested in residential and light-commercial products, I can highly recommend the surge protectors of Panamax; in particulary, we've had a lot of luck with their Max 8 Coax product shielding broadband over coaxial cable:
The Panamax products tend to work interior to a building. [By the way, as far as interior wiring is concerned, did you know that in three-color wiring, the white wire and the bare wire are connected to the same mount in your circuit breaker box? I.e., once you get inside a building, white and ground are one & the same.] For products exterior to a building, I'd take a look at Citel, of Miami, FL [especially their P8AX series for coaxial cable lines, although they have myriad products for POTS and CAT5, as well]:the white wire and the bare wire are connected to the same mount in your circuit breaker box
A few years ago, there was a change in the code, which now requires white and ground to be anchored to two different mounts, but in almost all existing construction, that won't be the case.
Tell your bosses to either learn about and purchase protection equipment, or don't and learn about lightning damage, then buy new equipment and THEN buy protection equipment.
Arresters typically come with insurance; if the protection fails to protect, they pay you. If this fails to catch your PHBs's attention, start wearing a scuba diving outfit to work and tell them that the rubber is to prevent you from getting killed by the lightning, and oh, by the way, would they mind very much if you took out life insurance policies on them?
"I may be synthetic, but I'm not stupid." -- Bishop 341-B
Yes fiber is NOT an end-all solution, but using fiber will isolate network segments from lightning strikes. If a bolt hits a computer here, it doesn't fry a computer 10 miles away. Nonetheless, the original poster doesn't have the luxury of replacing all his copper with fiber.
It's assumed that the equipment is connected to surge protectors on the power line; I believe the original poster was wanting to protect the network cabling from lightning strike.
By far, the most important thing to do is grounding (or "earthing" if you're in the UK). Have the chassis of your equipment connect to a good earth ground. Have the shield of your cable connect to a good earth ground. And by all means, make sure your surge suppressor is plugged into a good earth ground!
The purpose of the ground is twofold: 1) drains the buildup of static electric charge; and 2) provides a path of least resistance to ground (instead of through your sensitive equimpent) in the event of a direct lightning strike or a short to powerline.
The purpose of a lightning rod is not necessarily to "attract" lightning, but to drain the electric charge from the air. You want your lightning rod NEAR the equipment or structure you are trying to protect. To place it far away expecting it to "attract" lightning will leave you disappointed. Occasionally lightning DOES hit a rod; in this case, had the rod NOT been there, it would have hit the equipment it was placed to protect.
I've seen it over and over and over again, a surge protection device that's connected to an outlet without a ground prong. Let me say it in big, bold letters so it gets into your skull: AN UNGROUNDED SURGE PROTECTOR IS NO PROTECTION AT ALL. It's a bit like a condom with a hole in it. When the surge comes, it blows up all over the place.
Give me my freedom, and I'll take care of my own security, thank you.
Thomas Edison was a Genius!! Lighting through air. So much better than lighting through wood.
I recommend the new low-power LED lighting. It's expensive, but it's mega-awesome.
With interbuilding cables, only earth-ground one end of the shield. Earth potential can vary by several hundred volts between buildings, even without the storms. If you ground both ends, you are creating a dangerous high voltage ground loop.
Fiber is definitly one of the best solutions for eliminating ground loops on inter-building runs.
I once worked for a telcomms comapny which amongst other things made most of the surge arresotrs used in Italian exchanges.
What I learned is that despite the fact that there are very many different solutions around, the simple and very effective solution uses a gas discharge device in paralell with a transorb (bi-directional zener). The transorb is very fast and has a high voltage, it briefly protects the line before the gas discharge device cuts in after a few milliseconds. The gas discharge device can pass high currents because once arced the voltage falls sharply, reducing the dissipation.
Varistor and other solutions are of little use for protecting data lines against lightning. Varistors are a good and economical solution for mains surge protectors.
When protection devices cut in, you will have big currents flowing, which in turn can generate large voltages if earthing is no good. The isolation built into ethernet standards is caple of withstanding bad earths, RS422/485, and worse 232, is not. Fit isolationg adptors to any serial connections which are not on the same electrical circuit.
Finally, a little home made device which will not recover, but will protect equipment against the biggest surges which could otherwise overload surge arrestors. Break open the cable and pass all conductors and screen through robust but small fuses. The fuses should be suspended just above a very good earth (2/3 mm from a girder that runs into the ground for instance). The wiring and fuses should be kept really short and close together. An easy way to realize this in pratice is PCB mount fuse holders mounted thougth holes drilled in a plastic board. Mount the board on your 'girder' or whatever and adjust the height so the lugs are 2/3 mm abover the surface.
And if you thought that was boring you obviously havn't read my Journal ;-)
Yeah, I'm in Winnipeg. Close enough for Canada. ;-)
;-)
Just listened to CBC on the way home from work - we have about 20 cm on the ground now, another 20 by tomorrow. Branches all over the place, power out, TransCanada closed... crazy, man, crazy.
Of course the farmers are loving it, and I can't blame them. About time we got some moisture into the ground. Lots of nitrogen, too. I can't complain. Besides, it gives me an excuse to stay in tonight and watch Calgary kick ass!
Corruptissima re publica plurimae leges.
Physical weight has nothing to do with it.
How Lightening rods work [PDF]
Then I can have my job back.
"It is times like this when /. needs a "-1 Wrong" moderation."
I notice your still at "0"
"RF EM waves produce AC in conductors. The grandparent was effectively correct."
He wasn't talking about RF producing AC in conductors.
[parent poster]
"Rf is basically AC current going thru the air."
Which it is NOT. It's an electromagnetic field.
"Many natural phenomena broadcast in the GHz range. The Sun is one such example. Lightning will also cause microwave interference, but not a lot."
Which is why I said most. The sun is rather irrelevent to our discussion unless your talking about a satellite.
"The shape of a lightning rod is irrelevant."
Not quite. YOU may actually want to read the PDF link I posted to another guy.
I sell and install radio equipment that is installed on towers that range in height from 40 to 1400 feet. The taller ones are guarenteed to get direct hits from lightning ~every~ thunderstorm. The key to preventing damage is grounding. It doesn't matter what kind of lightning protection you have if your site grounding is not up to par. In a commercial building situation, the power entrance to the building must have adequate grounding. Isolation transformers are a great help as well. Lightning can also enter buildings via phone and network cables so make sure the telco demarc is properly grounded.
:)
When I say properly grounded I mean #2 wire or better not a piece of cat 5 with all the wires stripped back and twisted together. The telco ground, the power ground and any other grounds must be tied together to prevent ground loops.
Get a master electrician that knows what he is doing to advise you.
On the rf gear I work on I like tripp-lite and polyphasor for protection.
I have seen the tripp-lite IB4 or isotel take such a huge hit that the rocker switch was blown completely across the room and the components inside were reduced to crumbly black bits that fell out the switch hole. I replaced it with another of the same unit and the equipment came right up. Then I gave it back to my salesman for a refund since they have a lifetime warranty!
Anyway spend the money protecting the entrance points from lightning damage. If you are protecting commercial buildings rather than individual computers then get high quality protection systems that give an indication when the protection fails.
It is important to remember that ground rods corrode away and have to be replaced. That lightning protection devices are only good for a couple of light hits or one big one. Then they must be replaced since they don't offer any protection anymore, though they still happily let power through. Lightning protection is a consumable not a one time purchase.
Grounding is primary, protection devices follow.
If you have serious problems, Motorola produces a manual called "R56". Do a site to R56 standards and you will be good to go though you won't have much money left
10Base5 was designed for running between buildings. If at all possible you should use fiber for that job, but if facing the choice of which segment to replace, get rid of all the 10Bast2 and 10(0)BaseT NOW.
Ground loops are a far more likely problem than lightening, and only 10Base5 has any protection for that. (and then only if your transceivers are designed correctly...)
Even still glass fiber is the only way to go. I'm just giving you a priority of replacing things.
I recently built a box and installed a home network down in Venice, FL that has been struck directly by lightning the previous summer.
:-/
the lightning hit the electrical mains (the meter + main breaker on the exterior of the house), which happens to have the POTS POP 6 inches away.
they had to replace nearly every electrical device in their house.
At my own home, i recently discovered that I've been running 15A worth of computer equipment (boxes, monitors, net gear, etc) on an UNGROUNDED line. (house wiring circa 1947, revised in 1970 and 1991) Did i mention i live in florida?
I pestered my dad to install a new (and PROPERLY GROUNDED) 20A line. All i have right now is an extension cord running to an unused 15A grounded outlet
there is one system at the other end of the house that's wired to my switch, i'll have to get a surge box for that sucker. Unfortunatly, my parents are too cheap to spend a few extra $ on a surge system on the house. Personally, I plan on burning a few hundred and setting up my own sub-panel with surge suppression/isolation from the rest of the house's shitty wiring.
Most of the other dwelling around these parts are 2+ stories high, not to mention the power transformer boxes on the utility poles at the front and rear of the house, and a few TV antennas and tall trees. this house may not exactly have a bulls eye on it, but too many of the surroundings do... aiee.
Logistical Chaos Officer http://www.slagg.org - LAN Gaming in Sarasota FL,USA
For my home network (and wired alarm system), I connected a 130V MOV (metal oxide varister) to each line. The other end of the MOV is connected to a 1 amp fuse. The other end of the fuse is connected to a good ground:
---Ethernet Lead 1 - MOV - 1A Fuse -\
---Ethernet Lead 2 - MOV - 1A Fuse --\
---Ethernet Lead 3 - MOV - 1A Fuse ---\
---Ethernet Lead 4 - MOV - 1A Fuse ----\
---Ethernet Lead 5 - MOV - 1A Fuse ----- Ground
---Ethernet Lead 6 - MOV - 1A Fuse ----/
---Ethernet Lead 7 - MOV - 1A Fuse ---/
---Ethernet Lead 8 - MOV - 1A Fuse --/
MOVs are open until the voltage exceeds the rating (130V in this case), at which point they become a short. So if the potential on the line exceeds 130V, the line is momentarily shorted to ground discharging it. If the current on the line exceeds 1 amp, the fuse will open.
While this wont help you in a direct strike (nothing will), it does prevent charge build-up and induced current (in the giant antenna that is your network wiring) as a result of nearby lightning strikes.
As a side benefit, I no longer get false alarms on my burglar alarm when there's a storm in the area.
After a bad storm, I check the fuses, but none have been blown in the last 15 years.
Can You Say Linux? I Knew That You Could.