Can lightening travel through house?

[pcdudedude]

If I have my computer completely unplugged. If lightening strikes can it travel out of the outlet, through the air and hit my computer anyway?

 

[StarChief]

Unless the god of thunder Raiden from mortal kombat busts through your window, shouts some gibberish and shoots lightning from his fingertips into your computer, you and your PC will be safe.

 

[mrmike_49]

more likely to hit you - you're a bigger target

 

[p_nut_uk]

Basically no, you would be the unluckiest sod in the world for that to happen.

 

[skit75]

It is possible for components to be effected by the electromagnetic interference that accompanies the strike. Not very likely but I suppose it is possible.

Lightning(electricity) will take the shortest path to ground. It would need a very good(odd) reason to jump out of a socket and have actual voltage hit your machine. There are too many paths of lesser resistance encountered, before it ever gets to this point. The EMI in theory could cause damage but I've never heard of this scenario.

 

[TechyInAZ]

Unless the god of thunder Raiden from mortal kombat busts through your window, shouts some gibberish and shoots lightning from his fingertips into your computer, you and your PC will be safe.

LOL right!

Remember, lightning getting into the ground is it's life's priority. So if it needs to use your PC to get to the ground then yes it will use that path. However coming from a socket it will just go into the ground part of the socket.

This has got to be one of the funniest threads on here.

 

[vrumor]

I think it is far more likely to jump out of the socket and to the foil hat the OP is wearing.

 

[JackNaylorPE]

There's a reason surge protectors exist.... a surge on the line can travel thru a house's entire electric system. It generally doesn't jump out across their air, doesn't need to if it is still plugged in. Unplugging it removes 99% of the risk.

Tree in our yard was struck in the Nor'easter before Sandy..... tree came thru a window next to the PC but didn't damage it.

 

[CompuTronix]

I had a point blank lightning strike occur at home last year. All my electronics were on UPS's and surge protectors, and otherwise well grounded on an electrical service which was bonded to a healthy ground rod. Fortunately I was sleeping at the time and wasn't near my computer, so I didn't witness the actual strike. All I saw was a brilliant flash through my closed eyelids accompanied by an instantaneous loud crash. The time interval between them was zero.

The electrostatic discharge took out a UPS, 2 surge protectors, an antenna, 2 receivers, a phone and it's power supply, a cable box, it's power supply and a section of cable, and a night light plugged into an outlet.

It also took out the motherboard in my PC which was fully connected at the time, but damaged no other parts. It took out the motherboard in a 2nd PC which was completely disconnected but in close proximity to the night light. The motherboard was damaged in a 3rd PC which was also completely disconnected, but a few feet away from the night light outlet. This PC's motherboard ultimately failed a few weeks later.

It just goes to show how unpredictable a lightning strike can be.

CT

 

[skit75]

This is as close as I ever get to these stories and I've been in the electronics field for 20 years. Reading about them on websites and viewing old ESD\EMI scare tactic videos in an effort to foster better practices.

 

[pcdudedude]

I had a point blank lightning strike occur at home last year. All my electronics were on UPS's and surge protectors, and otherwise well grounded on an electrical service which was bonded to a healthy ground rod. Fortunately I was sleeping at the time and wasn't near my computer, so I didn't witness the actual strike. All I saw was a brilliant flash through my closed eyelids accompanied by an instantaneous loud crash. The time interval between them was zero.

The electrostatic discharge took out a UPS, 2 surge protectors, an antenna, 2 receivers, a phone and it's power supply, a cable box, it's power supply and a section of cable, and a night light plugged into an outlet.

It also took out the motherboard in my PC which was fully connected at the time, but damaged no other parts. It took out the motherboard in a 2nd PC which was completely disconnected but in close proximity to the night light. The motherboard was damaged in a 3rd PC which was also completely disconnected, but a few feet away from the night light outlet. This PC's motherboard ultimately failed a few weeks later.

It just goes to show how unpredictable a lightning strike can be.

CT

So it seems like you have first hand experience that proves all these other commenters wrong.

 

[CompuTronix]

Well, Jack's comments had basically substantiated what I've said.

During my career as a medical imaging engineer specializing in MRI and CT scanners, which are all computer driven systems, I've seen a wide variety of damage to sensitive low voltage electronics subsystems caused by power irregularities, including those induced by direct or nearby lightning strikes due to severe weather outbreaks.

Although many of these systems are installed in hospitals with extreme attention to detail including isolation transformers, heavy surge suppressors and UPS systems that fill a power vault, and huge ground rods sunk to China, there's still no assurance that the electronics isn't vulnerable to the most serious power anomalies or lightning strikes.

Consider a CT Scanner Gantry which has an X-Ray Tube that operates at 140,000 volts. It draws current between the cathode and anode, which is similar to a controlled lightning strike that occurs out of design necessities in extremely close proximity to shielded 5 volt logic circuits.

X-Ray Tubes are unpredictable in terms of operational longevity, and will eventually "arc" to ground prior to failure. When this internal "lightning strike" occurs, it often does nothing ... but however well designed the system is, it can corrupt software, kill hard drives, take out circuit boards costing 10's of thousands of dollars, power supplies, high voltage tanks, electromechanical servo circuits, several different micro CPU's, network, control and communications boards, detector boards, the $100K+ X-Ray Tube itself, and God knows what else ... even fans!

Regardless of a service contract, just the OEM cost in parts can be staggering, not to mention the down time and round-the-clock tag-team troubleshooting and repairs to get the system up, aligned, calibrated and running properly.

So can lighting damage your computer ... plugged in or not ... yes it happens. The bottom line? You can never have too much circuit protection. It's rate in "Joules", so protect your jewels!

CT

 

[JackNaylorPE]

There's a lot of interesting conceptions out there .... the mindset comes up often that "you're puter is just fine with a $13 Walmart Power Strip"....anything more is a waste of money. I use a $13 strip on my cable box ... it's not mine

The workstations / kids gaming boxes / peripherals get decent $60 SP's / PS's .... the SOHO when we leave file server gets a 1500 VA sine wave UPS. Everything still gets unplugged in a storm.

And yes, I consider it well worth the investment in a quality UPS on at least the office or home file server .... gotta protect the "family joules"....

One time wife and I were running around the home office yanking plugs for a sudden storm that was rolling in and she was remarking .... if you married you know what I mean by "remarking" .... about why we gotta do this "after spending all that money on protection devices" for "the family joules"

I threw back "what about my "family jewels" ? She grabbed some tin foil outta the trash (someone's lunch sandwich wrap I guess) , threw it to me and said that was "that's all I'm going to spend on those" !

 

[CompuTronix]

One time wife and I were running around the home office yanking plugs for a sudden storm that was rolling in and she was remarking .... if you married you know what I mean by "remarking" .... about why we gotta do this "after spending all that money on protection devices" for "the family joules"

I threw back "what about my "family jewels" ? She grabbed some tin foil outta the trash (someone's lunch sandwich wrap I guess) , threw it to me and said that was "that's all I'm going to spend on those" !

That's great, Jack! Women ... they let you know exactly how much you're valued!

 

[Someone Somewhere]

I believe (don't have too much experience in this area) that your typical surge protector is not going to protect against a direct lightning strike to the building (without a good lightning rod). Almost nothing will.

The point of a surge protector is to clamp the excesses if your neighbour gets hit, or a powerline on the other side of a distribution transformer.

CT's gear got fried by all the energy around in the air - but that probably reduces with the square or cube of distance from the strike.

 

[westom]

So it seems like you have first hand experience that proves all these other commenters wrong.

What some assumed was protection also was not. For example, accurately noted is that earthing is essential to protection. So many have earthing that meets human safety code. That means only one incoming wire connects to earth. And all other wires carry surges directly into and destructively through household appliances - to also connect to earth. That is why he had UPS and other damage.

What is sufficient for human safety (ie National Electrical Code) does not define transistor safety (surge protection). Protection means earthing must exceed code requirements..

That UPS or power strip protector do not claim to protect from destructive surges. Sometimes make damage easier. The reason is obvoius. Protection means a surge connects low impedance (ie less than 10 feet) to earth. Neither that protector nor UPS claim to do that, have an earth ground, or have numbers that claim such protection. Any recommendation without perspective (numbers) is best ignored.

Protection is always about where hundreds of thousands of joules harmlessly dissipate. So one 'whole house' protector, properly earthed, connects direct lightning strikes to earth. Even the protector is not damaged. But again, that means every wire inside every cable connects to what does protection - earth ground. This proven solutioni that costs about $1 per protected appliance also is rated at 50,000 amps. Since a direct ligthning strike may be 20,000 amps, then even the protector is not damaged. Numbers are necessary to have a useful answer.

Best protection for TV cable is a hardwire from that coax to single point earth ground. Best protection does not even have a protector. And makes a low impedance (ie less than 10 feet) connection to earth. The only recommendations for earthing also got it wrong. Every wire (even coax) must connect low impedance (wire has no sharp bends) to single point earth ground. Otherwise the only protection is that superior one inside every appliance. Notice another critically important number - less than 10 feet.

Telephone wire cannot be connect direct to earth. So we do what a hardwire would do better - make that same connection to earth via a 'whole house' protector. All phone installations already have this proven solutioni installed for free.

Unfortunately AC electric - earthed to meet human safety codes - has no earthing for surge protection. So a best connection to earth is incoming on AC electric, through household appliances, and outgoing destructively to earth via phone lines or cable TV. What is damaged? Not the incoming path. Damage is on the outgoing path because the only proven protectoin from direct lightning strikes (and other destructive surges) was not installed.

If any wire inside any cable enters without first connecting to single point earth ground, then all protection is compromised. Protector or UPS adjacent to an appliance can even make damage easier. Those are often grossly undersized to fail. Since failure gets so many to recommend solutions that have no earth ground.

 

[Darkbreeze]

Unless the god of thunder Raiden from mortal kombat busts through your window, shouts some gibberish and shoots lightning from his fingertips into your computer, you and your PC will be safe.

Um, no, that's not true, necessarily. In the case of a direct strike, as indicated by CompuTronix in his post above, things can still get damaged. Consider:

Equipment which is disconnected from wall outlets and phone lines is
relatively immune to lightning damage. However, lighting energy is is not
just delivered by an electric current in the power lines and phone lines.
The path of the lightning current also is surrounded by an extremely
powerful and rapidly changing magnetic field. If metal objects are
immersed in a magnetic field, and if the field strength suddenly changes,
it will "induce" a voltage across the metal objects, and can create a
pulse of electric current through them. If the lightning takes a path
which travels very close to an electronic device, the magnetic field can
create a pulse of voltage and current in the components within the device.
Since these fields become weaker with distance, all this would probably
only happen if lightning struck the building.

If your computer, stereo, etc., has wires attached to it, these wires can
act as an antenna which "gathers" a larger pulse of current from the
lightning's magnetic field. For example, if a stereo amplifier is
disconnected from AC power, but if there are long wires attached to
distant loudspeakers, the long speaker wires can cause trouble. They can
pick up the lightning's magnetic "signal", and this signal may pack enough
power that it can damage the output transistors in the amplifier even if
the amplifier is unplugged from AC power.

 

[westom]

Nearby lightning strikes can induce thousands of volts on items designed to maximize that induction - such as a radio antenna. Tiny items, such as NE-2 neon glow lamps, are connected to that antenna lead. A massive 'thousands of volts' drops to tens of volts because its associated induced current is near zero - often less than a milliamp. A tiny current that can barely light that tiny neon glow bulb. But such numbers are ignored by many who recommend without first learning this stuff.

Induced voltage from a nearby strike is massive. But its current is so tiny that all electronics (in cars, in calculators, in a wrist watch, in mobile phones, in every household appliance, in emergency communication radios, in electric clocks, etc) makes that transient irrelevant.

Essential for separating popular urban myth from reality is numbers. Recommendations based in reality (including from this poster who was doing this stuff for decades) come with numbers.

If fields from lightning were so destructive, then lightning struck airplanes would crash. Aluminum does not protect from massive magnetic fields. But solutions, doing what the NE-2 neon glow lamp does, means massive lightning fields create no problem. Protection from induced fields is standard in all electronic designs. That fear of massive fields is always made subjectively - without numbers. Subjective claims are akin to junk science reasoning. Unfortunately many recommend by ignoring experience from others who actually did this stuff. And by ignoring the so many nearby strikes that routinely did not 'induce' damage.

 

[Darkbreeze]

A massive 'thousands of volts' drops to tens of volts because its associated induced current is near zero - often less than a milliamp. A tiny current that can barely light that tiny neon glow bulb. But such numbers are ignored by many who recommend without first learning this stuff.

Thousands of volts are not required to cause damage to sensitive components. Tens of volts, or less, is more than enough in many cases.

The ICs in computers are particularly sensitive to high voltage because
their transistors contain microscopically thin layers of glass. The glass
is so thin that just a few tens of volts can cause a small spark to jump
through the glass. When this happens, a hole is blown through the glass
layer, and the conductive layers on either side of the glass can touch
together. In technical language, the transistor has been "fried".

Also, many types of electronic parts (diodes, transistors, ICs) contain
extremely thin internal wires which connect the silicon components to the
heavier external wires. A large surge of electric current from induced
voltage can vaporize the thin wires in the same way as a fuse is vaporized
by overcurrent.

 

[westom]

If any appliance is damaged by tens of volts, then it does not even meet international design standards that exists long before PCs existed.

An example: this electronics interface chip demonstrates industry standards. Informed poster read numbers from data sheets. What does this Maxim data sheet say?
"+-15kV ESD-Protected"
http://datasheets.maxim-ic.com/en/ds/MAX1487E-MAX491E.pdf

Routine is for interface electronics to withstand 2000 or 15,000 volts without damage. Same IC, not part of the 'system' is not that robust. But again, we are in conflict because I did this stuff and you did not.

Ten volts can damage a semiconductor that is not part of the system. Once part of a system, then the same semiconductor becomes robust - withstanding thousands of volts without damage.

And yes, knowing this stuff is essential to meet international design standards - since electronics must be that robust.

Induces surges are destructive only when speculation (without numbers) assumes it. Damage comes from direct strikes. A lightning strike far down the street can be a direct strike incoming to every household appliance. If any fail, often is it only a few due to protection already inside every appliance. However, even that damage is easily averted for about $1 per protected appliance.

Please do not censor me again because you do not like what 40 years of electrical design experience says. Please learn from numbers and datasheets before denying what was standard even long before PCs existed.

 

[Darkbreeze]

Once again that's not true. Devices may be designed to withstand more than tens of volts, if the voltage is being delivered through normal channels, but if the voltage is induced, components that were beyond the point of any protections in the circuit layout might be very susceptible to very minor voltages.

 

[westom]

The datasheet make obvious that voltage induced on channels intended for single volt signals must not cause damage. Routine protection for ethernet signal connections (ie less than 10 volt signals) means up to 2000 volts on that IC cause no damage. Newer technology semiconductors now withstand up to 15,000 volts without damage. Numbers from manufacturer datasheets that contradict your subjective claims.

All electronics already have robust protection. A homeowner's concern is a rare transient (maybe once every seven years) that might overwhelm protection already inside all appliances. This type of surge must dissipate outside - and must not be inside the building.

Facilities that cannot have damage spend less money on a proven and more robust 'whole house' solution. So that protection already inside appliances is not overwhelmed. A homeowner can do this for about $1 per protected appliance using a protector designed to not even fail on direct lightning strikes. These are provide by other companies of integrity.

 

[Darkbreeze]

To answer your question OP, yes, it's possible for damage to occur to items that are not directly connected to the outlet in the case of a direct lightning strike, but the chances of it, especially on a modern, properly grounded system, are minimal. It can, and has been shown to cause damage to some of the more sensitive hardware on occasion though. But in most cases, it's the fire from the lightning strike you'd need to worry about more though. Doesn't matter if your hardware survives the strike, if the house burns down.

JK, kinda.

 

[turkey3_scratch]

If I'm correct, lightning actually travels from the ground up.

 

[westom]

If I'm correct, lightning actually travels from the ground up.

You have confused the construction of a plasma path with the actual surge current. That construction can take milliseconds. The resulting surge is done in microseconds.

During a surge, current is everywhere in that path simultaneously. If that current is not inside a house, then that current is not incoming and outgoing via some appliance - no damage and no fire.

Best protection means lightning need not enter a building. If anything needs protection, then everything needs protection. One 'whole house' protector is properly earthed to protect everything without even disconnecting. So that lightning need not travel through a house. So that protection already inside every appliance is not overwhelmed.