A little off-topic - Lightning and Electrical Components
 

Hey there, I've been curious about this for a while and I know you guys in this community are probably pretty qualified to answer this question. I'm not sure if this is the right sub-forum, if not, I'd be happy to move it to somewhere more fitting (Electrical seemed the most relevant).

I'm wondering about lightning strikes, as to why people (At least some people who I know) are so concerned about surges and power outages damaging electrical components. Specifically (And I think this is due to the misconceptions that a lot of people have about computers - imagine 'ohhh, shiny'), people seem to think that computers can be seriously damaged by lightning strikes.

Now, my natural instinct is to say that this is not accurate, plainly because of all the measures we have in place to prevent such things from happening (Eg. Breakers, Surge protectors in transformers, surge protectors in power bars, fuses in appliances, etc.), but is my instinct not correct in this situation? And if so, what are the actual chances that such damage can occur? (For example, is a surge to the power brick on my laptop capable of affecting the laptop itself because the laptop is capable of powering itself with it's battery)

If my instinct is correct, I'd love to understand what exactly goes on in the electrical components (Eg. Surge protectors, breakers) to stop surges from damaging components.

I'm not a huge electrical guy, so layman's terms are appreciated :)

Thanks,
Joel

Re: A little off-topic - Lightning and Electrical Components
 

The odds are low...but the risk is real. Lighting packs a real wallop. Search google images for computer lightning damage.

Re: A little off-topic - Lightning and Electrical Components
 

It is late and my brain isn't functioning 100%, but yes surges from lightning strikes can and will damage electrical components, especially semi-conductors. Just a few pictures below I found from the internet show some possible damage in a computer.




While you are correct in that there are a lot of protections in place in the electrical system to prevent damage, transients (short lived changes essentially) due to power outages/surges, lightning, electrostatic discharge (ESD), etc. can be very difficult to protect against in all situations.

Most components have an absolute maximum rated voltage that can be applied to it. Exceed this and you may have a latent issue that will show up years down the line, or immediate destruction. Lighting for example will introduce an extremely large transient that will destroy pretty much any component not specifically designed to suppress lightning. Transient voltage suppressors/protectors are generally used for protecting against ESD and lightning up to a rated level (standardized) and generally use the properties of various electrical components to create a low resistance path away from the sensitive electronics.

The wikipedia page on Surge protectors is actually not too bad and provides a starting off point I suppose. Of course I'm assuming some basic knowledge of electricity here.

Feel free to ask any questions or whatever, even over PM! I'm probably halfway incoherent since it is past my bed time, but I'll be happy to respond tomorrow.

Re: A little off-topic - Lightning and Electrical Components
 

I agree. The odds are low. Damage is very real. Not sure about scrambling to unplug every computer. I dealt with lots of computer damage in the 90's from strikes coming from phone lines but it's different with network connections now. All devices are susceptible, but I'm not sure it's as important. I still remember a instructor stating that there is no certain protection from a lightning strike. I protect the really important things by pulling plugs. I can do without for a few minutes while the storm passes.

Re: A little off-topic - Lightning and Electrical Components
 

Lightning suppression can do only so much. We're talking about mega-voltage and amps of current moving around really sensitive electronics.

Today's digital electronics operate with very low-voltage/low-power, primarily to preserve battery life and reduce thermal issues. There are devices in the cRIO operating on 1.2V power supplies whose can fail with transient voltage spikes less than fractions of a volt for less than milliseconds. Radiation coming through the Earth's atmosphere and magnetic field can upset circuits and wreck havoc with programs if not corrected. Small voltage spikes can literally cook IC circuits causing permanent damage.

When circuit boards are being assembled and handled with such parts, serious precautions are taken to avoid ESD damage: controlled humidity, conductive bags, containers, benches, floors and garments, wrist straps, air ionizers, etc.

Having proper grounding and adequate transient protection on power inputs (or better, UPS systems) is essential for protecting against lightning. But you can kill your electronics pretty easily with a static spark in the winter too.

Re: A little off-topic - Lightning and Electrical Components
 

Due to advertising, most failures get blamed on a surge. All appliances contain protection superior to what might be attached to its power cord. A destructive surge, large enough to overwhelm that protection, occurs maybe once every seven years. So any failure gets hyped as if surge damage.

Most failures are manufacturing defects. One example were electrolytic capacitors made with counterfeit electrolyete. Most other failures are speculted into "it must be a surge".

Your telco's CO, radio stations, munitions dumps, etc all suffer direct lightning strikes without damage. The solution has been well understood for over 100 years. But is not promoted by advertising, retail salesmen, and hearsay. So most have never heard of the well proven solution. Most have only heard of another completely different device, also called a surge protector, that does not claim to protect from typically destructive surges. Some numbers follow.

A destructive surges is a microsecond event. A connection from the cloud to distant earthborned charges. First that current exists at the exact same time everywhere in that path. Then much later, something in that path fails. To be damaged, an appliance must have one incoming surge wire. And other completely different outgoing wire. That is electricity. It does not enter an appliance, do damage and just stop as so many are told to believe.

Fuses, circuit breakers, a UPS, or anything else that might stop a surge take milliseconds to respond. Surges are done in microseconds. Nothing stops a surge. As in nothing. Nothing inside the house absorbs a surge. Surges are hundreds of thousands of joules. View numbers on the most popular protectors or UPS. They only claim to absorb hundreds of joules. A surge easily blows through such devices. Protection is always about where energy is absorbed. Destructively inside a building. Or harmlessly outside.

Electronics atop the Empire State Building may suffer 23 direct strikes annually without damage. The number was 40 for the WTC. Routine is to suffer a direct strike without damage. But that means relearning a concept originally taught in elementary school science. Franklin's lightning rod.

Lightning seeks earth ground. A best electrical connection was via wooden church steeples. Yes, wood is an electrical conductor. But not a very good conductor. So lightning, maybe 20,000 amps, will create a high voltage in that wood. From high school physics. 20,000 amps times a high voltage is high energy. High energy dissipates in wood resulting in steeple damage.

Franklin simply put a lightning rod on that steeple. Does the rod do protection? Of course not. The rod is only a connecting device to earth. 20,000 amps will create a near zero voltage due to a connection (a wire) to earth ground. 20,000 amps times a near zero voltage is near zero energy. Near zero energy dissipates on that connection. Hundreds of thosuands of joules dissipate harmlessly in earth. Most important is the earth ground and its connection - not the rod.

A lighting strike to AC wires far down the street is a direct strike to all household appliances. The incoming path IF that surge is permitted to go hunting for earth inside the building. Nothing will stop that destructive hunt if a surge is inside. As in nothing.

Informed consumers and all faciliitles that cannot have damage, instead, earth a 'whole house' protector. With a connection that is low impedance (ie 'less than 10 feet') to earth. Wall receptacle safety ground obviously is not an earth ground (excessive impedance, much more than 10 feet, etc). A surge connected to earth via a wire (cable TV, satellite dish) or connected via a 'whole house' protector (AC electric, telephone) need not enter a building. A surge connected to earth before entering does not hunt for earth destructively via household appliances.

Protection was always about energy not even inside. But advertising says a 2 centimeter part inside a magic box will stop or absorb that energy.

Nothing inside will stop, block, or absorb a destructive surge. Once inside, that surge will find earth destructively via appliances. A minimal 'whole house' protector is rated to connect 50,000 amps harmlessly to earth. Then no surge is inside. Even that protector remains functional after a direct lightning strike - as numbers confirm. Protection has been performed that way in every facility that cannot have damage - even 100 years ago.

Protecting the building is about earthing lightning rods. Protecting appliances is about earth incoming utility wires; either with a hardwire or with one 'whole house' protector.

Earthing (not a protector) is the most important component of any protection system. A lightning rod is only as good as its earth ground. A protector is only as effective as its earth ground. Most educated by advertising do not even understand why the art of protection and most all attention should be refocused on earthing. Do not even know the best protector costs about $1 per protected appliance.

Re: A little off-topic - Lightning and Electrical Components
 

One correction:

Surge protectors can absorb hundreds of joules... but redirect much more.

By the way, do you happen to be the westom at LinuxQuestions.org?

Re: A little off-topic - Lightning and Electrical Components
 

If a 100 amp surge is incoming to the protector, then where is the outgoing path? The critically important term was low impedance (ie 'less than 10 feet', no sharp wire bends, etc). A 'whole house' protector has that. A completely different device adjacent to an appliance: where does that current go? Sometimes destructively to earth via any nearby appliance.

Once that current is inside, it will hunt for earth destructively via appliances. An adjacent protector can only do two things: 1) block that current or 2) absorb that energy. Many have observed appliance damage because an adjacent protector earthed that current destructively through nearby appliances.

Protector adjacent to an appliance can block what three miles of sky could not? Or somehow absorb hundreds of thousands of joules? Protection is always about where energy dissipates. Always.

What happens to a 100 amp surge at a protector and appliance? 50 feet of AC wire might be less than 0.2 ohms resistance to the breaker box. But the relevant term is repeated often: 'low impedance'. That same wire may be 120 ohms impedance. 100 amps times 120 ohms means a protector and appliance is at something less than 12,000 volts. Why would a surge find other paths to earth destructively via nearby appliances? 12,000 volts. Excessive impedance.

The adajcent protector can only block that current or absorb that energy. Otherwise it an only divert that surge detructively via appliances. Fortunately, most surges that destroy grossly undersized protectors are too tiny to harm adjacent appliances.

Low impedance is why a 'whole house' protector makes a 'less than 10 foot' connection to earth. No sharp wire bends. Ground wire not inside metallic conduit. Ground wire separated from all other wires. That ground connection - not the protector - is most important for protection.

That adjacent protector only says it will absorb how many joules? Where is any number for protection? Does not exist. They need you to believe it somehow stops or absorbs surges. Otherwise it can only divert that surge detructively into any nearby appliance. Only item that does protection - single point earth ground. Only effective protetors connect short to and can divert energy harmlessly to earth. Protection is always about where hundreds of thousands of joules dissipate. Always.

Re: A little off-topic - Lightning and Electrical Components
 

An old saying in the ham radio community is "the only thing predictable about lightning is it is unpredictable". While broadcast stations with tall towers do have protection to try and prevent damage that doesn't always work. Lightning has a few particular issues that make damage control difficult. We are talking kiloamps with rise times in the few microseconds and millions of volts. Mechanical devices like breakers and fuses will not respond to that kind event. Should a strike occur near your device, the resulting pulse can jump across the protecting device and still take out a lot of stuff. The pictures above are nothing, they were likely caused by a component failure or power supply fault. A lightning strike would have left a burned hole in the board.
Remember Ohm's Law. Calculate out the voltage developed across one ohm at 40,000 amps. So a bolt strikes your phone line in the backyard, roars up the line to your house and the first thing it encounters is a lighting block that has one side tied to a #10 wire that ties to you cold water supply pipe. The #10 is .001 ohms per foot and is ten feet long, the copper supply pipe is .0001 ohms per foot and is 20 feet long before it touches earth outside your house and then it reaches dry ground. Assuming that the arrestor doesn't disintegrate and ignoring that the water in the pipe turns to steam instantaneously and that the #10 wire doesn't vaporize, several thousand volts will be developed across the wire and pipe. Once outside, the ground dissipates the current but there will be a potential spread across your front lawn. If you are standing out there with your legs spread out, there could be a difference in potential between your two feet of several thousand volts.
I have seen lightning bypass the protectors and travel on the outside of a coaxial line and then jump into a transmitter and take out the final amp. I have seen lightning come down a tower that is grounded, jump six feet to a house, strike the water pipes and blow all the fixtures in the house as the water turns to steam at high pressure. I have been asked to repair TVs, computers, and VCRs that were taken out in a nearby strike. Some only needed a fuse, others, there was nothing left of the boards near the power cord. Just charred circuits and a lot of residue on the case where the components that blew up were left. Even on Sears, when it gets struck by lightning (several times a year, 50-100) the current travels through the building, down the 120 stories to the ground and then presumably to the Chicago River a half block away. If you look at the video I linked a few weeks ago, the lightning protection is not visible because the entire structure is the protection. Everything you see is bonded to building steel.

Re: A little off-topic - Lightning and Electrical Components
 

If you want to completely protect electronic equipment from lightning, unplug it and put the device in the middle of the room, as far away from anything conductive as you can. This is probably only necessary when there are clouds in the sky.

Re: A little off-topic - Lightning and Electrical Components
 

Launching it into space would be a much more complete solution, provided you shield it from cosmic rays and solar winds. Also, it is best to implement the protection if clouds are anywhere in the area since lightning doesn't always travel straight down.

However, if you read on in that Wikipedia article I linked to, the idea of using lasers and rockets to trigger the lightning along a known path sounds interesting.

Re: A little off-topic - Lightning and Electrical Components
 

A lot of awesome responses, I learnt a lot! Thank you guys.

Re: A little off-topic - Lightning and Electrical Components
 

Particularly this rocket. :cool:

On the subject of lots of electronics, take a look at this Emirates A380 getting struck. Pretty neat looking, and obviously the airplane is designed to keep these strikes from disabling any systems.

Re: A little off-topic - Lightning and Electrical Components
 

Re: A little off-topic - Lightning and Electrical Components
 

Interesting story on planes. As I was talking to Dean at the Einstein weekend, he mentioned his plane was struck recently, taking off a small section of the wing tip.

Re: A little off-topic - Lightning and Electrical Components
 

Having worked for a 'large defense contractor' who designs commercial and military aircraft engine controls, and having performing EMI, fire, and lightning testing, I can tell you the qualification requirements for just the engine controller itself are...tough. Then again, if the the engine control fails, well physics takes over in its inexorable fashion even if the rest of plane is working just fine :)

For an example, you can look at the MIL-STD lightning test for aircraft:
http://www.everyspec.com/MIL-STD/MIL...TD-1757A_4242/.

During this test, the 'lightning simulator' must be capable of delivering up to 1.5 MILLION volts at a peak 200,000A (average 2000A). This is applied both as an air discharge like a normal lightning bolt, as well as a direct discharge as if the item under test was part of the conduction path from a different object that was struck. Scary stuff ::safety:: Even crazier is the thought of a lightning strike hitting the fuel tanks of an airplane (this gets tested!)

In terms of your home protection, here's some examples of what typically protects your telephone lines: http://bourns.com/data/global/pdfs/b...duct_guide.pdf The little gray 'telephone' box found outside your house would contain those protective devices.

The protection on a circuit card is typically "secondary protection" if it exists at all, but a properly designed protection scheme on a card can protect against 1500V/100A microsecond-type surges repeatedly. Not the same class at all as a direct lightning strike, but if lightning strikes the back of your computer there isn't much that you can really do at that point :D

Re: A little off-topic - Lightning and Electrical Components
 

Nowadays, like various other posters said, the risk is miniscule, because of all the protection devices we have. However, we have the devices because, at one point, a lot of computers got damaged by electrical storms. Now, they don't. As long as a person has their computer connected to a surge protector, it will be protected against surges, and there is no reason to worry.

Re: A little off-topic - Lightning and Electrical Components
 

Best protection is not on the power cord. That protection is inside appliances. For example, 1970, 120 volt electronics would withstand 600 volts without damage. Today, that same number is thousands of volts.

Or view datasheets. For example, this interface semiconductor from Maxim will protect up to 15,000 volts as defined per IEC 61000-4-2:
http://datasheets.maxim-ic.com/en/ds...7E-MAX491E.pdf

Today's more robust computers routinely make a 2000 or 15,000 volt transient irrelevant. A consumer's concern is an anomaly, maybe once every seven years, that can overwhelm that protection.

Informed homeowners earth a 'whole house' protector to even make that anomaly irrelevant. Protection that costs about $1 per protected appliance so that even direct lightning strikes to incoming wires need not damage anything. Need not even damage the protector.

Those near zero adjacent protectors with obscene profit margins are not the reason. Better protection is routinely part of every appliance design.

Re: A little off-topic - Lightning and Electrical Components
 

To be a little more precise, there is a difference between surge protection and lightning protection. Surge can occur during a lightning event. However, they are more often caused by electrical distribution and generator issues. Heavy loads by local users can cause brownouts and surges when the load goes off line. Even in Chicago it is not unusual to get small pulses in the 150 v(RMS) range or sustained voltage in the 90-95 range. While most international supplies are designed to handle these transients, they do as much with power supply design and surge protectors.
While a lightning strike could be clamped with one of these devices, a large spike would destroy most of these types used in consumer equipment. True lighting protection make take the form of spark gaps, motorized breakers, event detectors etc. While not usually found in consumer equipment, I have found spark gap (gas discharge) in devices I have worked on. These devices are usually installed where the power wiring enters the equipment or at the power entrance to the building. Antennas (support towers as well) will have some type of spark gap at the base with one side bonded to the grounding system or radials of the antenna. Many transmitters for tall towers, use a device that senses nearby lightning strikes and trips the transmitter to off and removes the output to prevent damage to the transmitter.

Re: A little off-topic - Lightning and Electrical Components
 

I dont know if anyone mentioned this but lightning is also a natural Electo Magnetic Pulse so in theory if any electronics are outside they can be really damaged

Re: A little off-topic - Lightning and Electrical Components
 

The parts Al mentions here are Gas Discharge Tubes similar to the Bourns part in the link I posted, and they are part of an FCC required protection network for your telephone interface box on your home and the Central Office (telephone company). Telephone lines, particularly in rural areas where the lines are long and exposed, are routinely struck and equipment on both ends is expected to survive this. Back when there were wired telephones (or landlines at all at this point :rolleyes: ) a user would probably be disappointed if an incoming surge continued down the wire inside your house to a handset you were holding :ahh:

Those numbers represent an ESD event, NOT a lightning surge. Volts, while important, are not the whole story. Lightning and ESD are very similar in that the duration and edge rate of the voltage event are very short. The big difference is that the current delivered during the event is measured in kiloamps for lightning, and microamps for ESD, so the POWER delivered in those events is significantly different. On a dry day, a 15kV ESD event from scuffling on the carpet and hitting a doorknob can jump ~0.25", and it stings but you're alive. If you got were close enough to a 15kV transmission line to provide a convenient path to ground, where the line is capable of delivering 10s or 100s of amps, you're going to have a bad day!

Let's talk about a recent example of how robust today's electronics are. If you can recall the 2009 game Lunacy, where we routinely were generating static both on our bots and ourselves, the driver stations would often 'flake out' or the ethernet ports would die (electrically, not just mechanically, that was a different issue :rolleyes:) Inside the blue box there was a chip (a PHY, the physical interface to an ethernet cable) which had no external ESD protection circuitry on it. The result? If a static discharge occurred to the cable, or even nearby enough to couple onto the cable, the PHY chip could see voltages that it was incapable of withstanding, and either go into an unknown state or even burn out. Ok, so this was a small yield, custom box that was built for FIRST, but a real commercial product sold to millions of people using a common interface couldn't POSSIBLY have this type of problem, right?

Well, here's a fun story. During some ESD testing, I was zapping a T1 interface board I designed using an ESD gun set to 15kV to ensure that it would operate normally if the service technician decided that static straps were for sissies :) While I'm doing this, one of the engineers on the other side of the lab (~20 ft or so) says "What the heck?". The USB mouse he was using was disconnecting and reconnecting rapidly from the computer, and eventually disassociated completely until unplugged and replugged in. Keep in mind, I'm 20 feet away on a bench that is grounded and has no medium connecting my equipment to his computer or mouse except the air (and some very indirect sneak paths back through the power panel everything eventually ties to). Standard USB mouse, standard PC, doesn't work correctly during an ESD event that isn't even nearby!

Well, there goes 30 minutes of my workday, hopefully some of this was educational then I can charge this to 'Community Service' :cool:

Re: A little off-topic - Lightning and Electrical Components
 

Eric,
One of my professors was a professional witness in just such a suit. The person was using a pay phone with the armored handset and cable when the line was struck by lightning. The resultant arc to their head, took out the hearing on one side.

Re: A little off-topic - Lightning and Electrical Components
 

And, as a result, lighting voltages can be higher if that larger current is all but invited inside. Newer appliances have become even more robust.

A point summarized for layman - the executive summary - all appliances contain some of the best protection found inside a building. And not by using surge protectors. Best protection means a surge current gets earthed outside. Otherwise that current will hunt for destructive paths to earth via appliances.

Why is a minimally sized 'whole house' protector rated at 50,000 amps? Because it must earth even a direct 20,000 amps lightning strike. And remain fictional. If earthed, then superior protection inside all appliances is not overwhelmed.

What was a standard for 120 volt electronics appliances before 1970? Up to 600 volt spikes on AC mains without damage. Today's appliances are required to withstand even higher numbers. Some adjacent strip, rated at near zero joules, does not even claim to increase protection. Sometimes a power strip protector has even compromised protection inside the computer.

Earth a 'whole house' protector so that a rare surge - maybe once every seven years - need not damage anything. Need not overwhelm existing and now even better protection already inside appliances.

Re: A little off-topic - Lightning and Electrical Components
 

BTW,
There is an interesting article in this month's National Geographic on lightning. It covers a man who is using a very high speed camera to catch a lightning bolt in action. It is really a cool camera.

Re: A little off-topic - Lightning and Electrical Components
 

Also interesting is a recent article in Scientific American. Lightning involves quantum physics - in particular electrons and positrons. Lightning is a seriuos source of x-rays and gamma rays. Accidentally discovered by a satellite while doing research on the sun.

One paragraph has me rather confused. One lightning strike to an airplane results in a human's entire lifetime exposure to gamma rays. They did not provide numbers. So I am not sure I got that right.

Re: A little off-topic - Lightning and Electrical Components
 

Al,

A coworker pointed this video out to me today and I think it may be this exact person.

http://apod.nasa.gov/apod/ap120723.html

This is a really cool video. If you watch carefully enough you can see the return stroke (bright flash) initiate from the ground and trace its way through the ionized air up to the clouds.

Re: A little off-topic - Lightning and Electrical Components
 

Understand that you are not actually seeing the electricity flow. That riser is simply the conversion of air to plasma. The actual surge current is in microseconds. Occurs after a conductive path from cloud to earth is slowly constructed.

Re: A little off-topic - Lightning and Electrical Components
 

Kevin,
The article is about a guy named Tim Samaras. His camera weighs in at 1600 lbs and shoots 1,440,000 frames per second using a three sided mirror spinning at 360,000RPM. It has 82 video processing boards and was originally designed to analyze above ground nuclear tests.

Re: A little off-topic - Lightning and Electrical Components
 

Can he shoot balls with that mirror? I guess it would be a little overweight for a FRC bot.

Re: A little off-topic - Lightning and Electrical Components
 

It could but only at the speed of light.