What happened here? ( Electrical Storm Question)

Factual Questions
1

I love tropical thunder storms! I watch in awe the torrential rain and fierce lightning strikes. I love nature’s firework display.

I was watching one such storm a few days back from my 40th Storey apartment balcony. As the storm moved closer the rain started coming onto the balcony so I went back inside my apartment.

A few minutes later all power was lost in my apartment followed in less than half a second by the loudest thunder “crack” I had ever heard. (I didn’t see a lightning flash maybe it occurred on the other side of my building.)

Almost Immediately the power came back on TV, laptop, Aircon everything!

Now normally if I lose power momentarily things like the TV restart but in standby mode. If I get a power surge am supposing all the circuit breakers would have tripped.

What happened to my power?

2

You should note that a balcony provides very little protection against lightning. The chance of getting struck is admittedly rather small, but there is a chance that you could be struck and killed while watching a storm from your balcony.

Power companies have breakers just like your home or apartment has breakers, only the power company’s breakers are obviously a lot bigger. In your home or apartment, if a breaker trips, you have to reset it yourself. That’s no big deal for someone in a home, but if you are the power company and the breaker is located 15 miles away, it’s a bit more of an issue. Since most power faults are transitory (a lightning strike, or a tree limb blowing against a power line in high winds, that sort of thing) the power company uses automatic reclosers to reset their protection devices. Reclosers are programmable, but most power companies set them up to turn the power back on one or two times very quickly (within a second or two), then if that doesn’t work they try again maybe a minute or two later, and if that doesn’t work they give up completely and it takes someone from the power company to go out and reset it.

So, what happened here was lighting tripped the power company’s protective device on the line, and the recloser turned the power back on.

Most devices can withstand a momentary power loss. Your typical electronic device has capacitors in it which filter off variations in the incoming power and will provide power to the device for a small amount of time if the incoming power goes away. Exactly how long this “small amount of time” is varies from device to device. It might be a tenth of a second or it might be a second or two. It all depends on how the folks designing it made its power supply. Many devices will ride out a quick glitch in the power like what you experienced.

Not necessarily.

There are different types of breakers and protective devices.

Your typical Joe Average breaker is an overcurrent breaker. It trips when you get too much current flowing. This is good for stopping your house from burning down if there’s a dead short somewhere, but they typically trip at something like 15 or 20 amps, and it takes much less current than that to kill a person. This type of breaker also won’t trip just because there is an overvoltage surge. It will only trip if that surge happens to result in a fault which draws enough current to make the breaker trip. You can blow up your TV and computer and all sorts of things without tripping this type of breaker.

A GFCI (ground fault circuit interrupter) is designed to protect you. This measures the current flowing out one wire and back through the other. If they don’t match, the device assumes that the current has found an alternate path to ground (quite possibly through you) and shuts off the power. A GFCI might get tripped by a surge but might not. It’s not designed to protect against that.

An AFCI (arc fault circuit interrupter) is designed to stop your house from burning down from something like a faulty extension cord. This trips when it detects an arc on the circuit, even though there may not be enough current flowing through the fault to trip the overcurrent breaker. AFCIs aren’t designed to protect against lightning, but often the surge from a lightning strike looks enough like an electrical arc to it that the AFCI will trip.

There are also different types of surge suppressors that you can buy. These are not typically included in your house wiring, although they do make whole house surge suppressors. An apartment building isn’t likely to have them installed. Surge suppressors are not all created equal. Some can block much more of a surge than others, but to be fair, there really isn’t anything that can protect you from a very close lightning strike. There’s just too much energy in lightning. Many power strips have surge suppressors in them, but not all do, and in many (especially the cheaper ones) the surge suppressors aren’t very good.

3

the surge caused by the lightning may never have reached you.

as engineer_comp_geek explained the power utility breakers would have tripped due to the surge. any surge that got through might have been absorbed by those located just downstream of those breakers. in a city there are lots of users in a small area so a surge on the grid may not travel far.

surge suppressors in power strips do get used up, they can accept a certain total amount of surge before they no longer function (you may have power on the strip but no more surge protection). some will have an indicator if the surge function is still working. there are different methods and quality so this is going to vary between units.

to be safe some people unplug all valuable devices from the grids (power, telephone, cable tv) when large thunder storms are close (use your storm/backup tv and phones). if you use an external antenna you would disconnect from that too (except your storm/backup tv and radio). city people do tend to be less cautious because surges in the grids often don’t travel far so not many people are affected and external antenna devices are less common.

4

I must admit am a bit blase about electrical storms (apart from my fascination with the display). But my building is not the tallest in the area ( Less than a kilometre from me is a construction of what will be the tallest building in Manila … and guess who has bought off plan an apartment on the very top 68th storey!

But back to the original…engineer_comp_geek Thanks that would explain some things. The speed of light being so so much faster than the speed of sound would explain why I had the micro second transient blackout and then only after that heard the thunder clap ( and damn it was some loud crack) But I know that every week when the condo association does the emergency gen set tests, that when the generator kicks in, gets up to speed and synchs to a dead board, I get all my power back but stuff like TV and other stuff ( computer voltage stabilisers) come back on standby mode.

This one was a new experience for me.

5

With an emergency generator (1) they do not sync. In a newer ATS (automatic transfer switch) A small switch is pushed for 1 to 2 seconds. This starts the engine and a timer. When the generator is up to voltage the emergency circuit utility main is opened then the emergency power is closed. At least a second between the two.

Now if you have more than one generator it gets more complicated, and if it is a full building load system even more so.

6

That explains what happened to the breakers. Now appreciate why lightning struck what it did. The cloud must connect to earthborne charges. A shortest path to those charges (maybe miles away) is down from the cloud, through something to earth, and then through earth to those charges.

Tallest items are not necessary the electrically shortest path.

For example, one path is high voltage wires highest on utility poles. A better path to earth might be through appliances in your building. Or via the protection that all utilities provide in that distribution transformer.

Either lightning creates a short circuit from high voltage, through the transfomer to 120/240 volt lines. Or lightning connects harmlessly to earth via a ground wire from that transformer. Either way, electricity will continue to flow during that microseconds surge. And when AC power continues to flow (shorted) on that path.

So view what engineer_comp_geek has posted. Lightning flows to earth and is done long before any circuit breaker even starts to trip. But a circuit breaker must trip to disconnect utility AC electricity (called follow-through current) from that same (fault) path to earth. And so a circuit breaker trips - then resets. The fault (ie an electrical conductor called plasma) is given time to clear. Then AC power is restores. When restored, AC power no long takes a short circuit to earth. Instead it flow normally (again) into your condo.

Now if that utility transformer is not earthed and if you have not earthed a ‘whole house’ protector, then one destructive path to earth can be via your appliances. That is what every effective protector does. Either a surge is connected as short as possible to earth. Or a protector is ineffective. Ineffective as in power strip protectors that do not even claim surge protection in numeric specs.

Protection is always about where hundreds of thousands of joules dissipate. Surges (ie lightning) are absorbed harmlessly in earth. Lights out says some kind of fault (short) created by a surge is cleared by circuit breakers long after the surge ended.

7

Not very many people do unplug all their electrical devices or much simpler, to just switch off the main circuit breakers in the power panel. Short automatically reset outages are a nuisance, but can be damaging to refrigerators and air conditioners that are running (compressor running) at time of outage. There needs to be a bleed down time before the unit restarts and the unit will draw a large amount of current trying to start. This can weaken a circuit breaker and or damage the unit.
Another less common occurrence with a power failure is a low voltage problem. I am not informed as to what causes these but we see them from time to time. These low voltage failures do most of the damage to household electronics and other electrical appliances.
We do not recognize these problem as readily today as in the past because of the green lighting so many of us use. These florescent green lights will not light up at all so we do not know that its a low power condition like with the old incandescent light bulb that would just be dim alerting use to this low voltage condition. All our appliances are trying to run on this low voltage, high amperage (unless they have safety circuits for protection.

8

Because storms so routinely cause damage, the telco in every town powers off all phone service with each thunderstorm. If storms are a threat to household appliances (typically once every seven years), then the telco has even more damage (typically 100 surges with each storm).

Well, recommendations without numbers are bogus. The reason why some disconnect appliances with every storm: they were told what to think and never once demanded numbers. So, how often do you disconnect every bathroom GFCI, smoke detector, furnace, air conditioner, stove, and digital clock with each thunderstorm? The informed homeowner never does. The informed homeowner does not have destructive energy inside his house hunting for earth destructively via the TV and dish washer. That always means a ‘whole house’ protector. And every protector connected short (ie ‘less than 10 feet’) to that single point earth ground. Ground that both meets and exceed post 1990 National Electrical Code. Upgrading that means no changes to any interior wires (even if the house only has 1930 wires). Upgrading a completely different ground - earth ground.

Low voltage is harmful to appliances such as refrigerators and the furnace. Low voltage is never harmful to any electronics. Why do you sometimes even design circuit inside electronics to create low voltages? Because lower voltages, in some cases, is even better for electronics.

All appliances (motorized and electronic) contain serious protection. Informed homeowners are only concerned about electrical anomalies that overwhelm protection inside each appliance. For motorized appliances, that is the slowly rising voltage that occurs when power is restored. For all appliances, that is massive energy that occurs only for microseconds, that can blow across even open circuit breakers, and that do not cause damage if connected to earth BEFORE entering a building. Microseconds - anther in a long list of reasons why ‘magic box’ that would stop or absorb a surge is also called a scam.

Early 20th Century Ham radio operators would disconnect their equipment. Even put the antenna lead inside a mason jar. And still suffer damage. Nothing stops a surge. Damage even 100 years ago was averted when the antenna lead was connected to earth. A fact that should have been obvious in elementary school science when they taught Franklin and his lightning rods. A fact that is hardest to learn once someone has been educated by retail advertising selling ‘magic box’ solutions.

We run everything during every thunderstorm. May have even had direct lightning strikes. And would not know. Effective protection for every household appliance - including every GCI on the kitchen counter - means earthing a ‘whole house’ protector. Then direct lightning strikes are earthed without anyone even knowing a surge existed. Any protector that failed did no surge protection. Even the ‘whole house’ protector is not damaged by direct lightning strikes - if a homeowner learns from 100 years of well proven science.

9

What? Never heard of such a thing. What about all the people who were talking on the phone – wouldn’t they get cut off if the telco powered down? And it would be common enough that you’d hear about it. And you don’t.

In fact, phone usage often peaks during storms, because people are calling others to see if they are OK. Or just get on the phone because they are stuck inside and need something to do.

10

You got a cite for that? I’ve been on the phone during thunderstorms and that has never happened to me. I recall having heard a short click that seemed to coincide with a lightning strike on occasion, but never an outage.

11

No, they don’t. I’ve designed backup power systems for central offices. There’s a reason your telephone works during a power outage. (In face, they’re much more robust in handling the secondary effects of lighting strikes than anyone’s home could ever hope to be…)

They don’t shut them off during a thunderstorm, hurricanes, tornados, or earthquakes. If you think about it, there’s a good reason why…

But talking on a hard-wired phone during a thunderstorm? That’s just nuts!

12

And so you now know (or should have concluded) that those other posts about disconnecting are based in myths and hearsay. Why does your telco suffer 100 surges with each thunderstorm and no damage? How do they do this without disconnecting? Because disconnecting for protection is the myth promoted by junk science and retail myths.

Obviously disconnecting is insufficient and therefore futile. Because ‘as posted’ is what every facility does when surges are frequent and damage must never happen. Including every telephone CO in every town.
> Effective protection for every household appliance - including every GCI on the kitchen counter - means
> earthing a ‘whole house’ protector. Then direct lightning strikes are earthed without anyone even knowing
> a surge existed. Any protector that failed did no surge protection. Even the ‘whole house’ protector is
> not damaged by direct lightning strikes - if a homeowner learns from 100 years of well proven science.

Obviously your telco does not disconnect with each approaching storm. So how often is your town without phone service for four days while they replace their surge damaged computers? They don’t because they do not use disconnecting and because they use protection defined effective even 100 years ago.

13

Which is why so many operators, with headsets attached to incoming wires, were killed by lightning strikes to their heads? Death did not happen for one simple reason. Same solutions that should exist in every home today (and usually is not) existed in every telephone switching center even 100 years ago.

Protection from direct lightning for every home is simple. So that a homeowner would not know a surge even existed. So that even the protector remains functional. Most do not have that protection. And would not install it due to so many myths that promote ineffective and high profit ‘plug-in’ protectors.

Defined was how Ham radio operators stopped lightning damage in the early 20th Century. One starts by learning why effective protectors always have a short (ie ‘less than 10 foot’) connection to earth. And touch such protectors even in Lowes or Home Depot for less than $50.

14

It seems to me you should try switching power off and on very quickly for an appliance of your choice to see if it restarts or enters sleep mode. People have suggested automatically resetting breakers, but that doesn’t explain why your appliances restarted instead of entering sleep mode.

15

This is not true. Most electronic devices are designed to operate over a very specific voltage range. Operating under that range can cause the device to malfunction and possibly suffer damage. I used to work in a building that suffered brownouts quite often, and we lost a lot of electronic equipment due to undervoltages.

This is also not true. Consumer goods rarely have any serious protection circuitry on their power input.

Even the best surge protectors you can buy cannot protect you from a direct lightning strike. There’s just way too much energy in a lightning bolt.

Whole house surge protectors are a good idea. Most people don’t install them I think because a lot of folks aren’t even aware that they exist. Cost is also an issue. Those little surge protectors you get in power strips often aren’t very good, especially the cheaper ones. They’ll give you some protection against a surge or a spike, but not much.

16

Power supplies inside of devices have filtering circuitry which take the incoming power and convert it to a relatively clean, uninterrupted power source for the device. These filtering circuits include capacitors which supply energy for a short time if the power cuts out. Remember, when you convert AC to DC for an electronic device, the power in an AC line cuts off 120 times a second, so you have to have capacitors in there to provide power when the AC cycle is at or near zero.

How big those capacitors are and how long they’ll provide power depends on what the designer of the circuit decided to put in there. With some devices, those capacitors will drain completely in a very short amount of time (say, a tenth of a second, for example), where in other devices they will be able to hold up the power for much longer (maybe one or two seconds). If you have a short power glitch, like the one the OP described, these capacitors will not have fully drained and the device will continue to function normally. If the power is out long enough for the capacitors to drain, then the device will go into sleep mode.

So, if the power goes out and very quickly comes back on again, some devices will ride it out with no problem and some will go into sleep mode. It all depends on how quickly the power comes back on and how much energy storage is in the device’s power supply circuitry.

17 
 An engineer provides hard facts, underlying science, technical reasons, and manufacturer spec numbers with conclusions.  Otherwise it is only an ‘imperial decree’.    So, provided are numbers you forgot to provide.

Direct lightning strikes are routinely earthed without damage. Only those using feelings (no numbers) would deny that. 23 direct lightning strikes annually to equipment atop the Empire State Building without damage. 40 direct strikes to the WTC. You somehow know “Even the best surge protectors … cannot protect … from a direct lightning strike.” Nonsense. You are reciting hearsay from English majors and retail salesman who with high school education. Protection is routine in every telephone CO with every thunderstorm. Why do direct lightning strikes no destroy their computers?

Read manufacture spec numbers from ‘whole house’ protectors. A direct lightning strike is typically 20,000 amps. A minimal ‘whole house’ protectors starts at 50,000 amps. Anyone can go to Lowes or Home Depot. Read numbers on a Cutler-Hammer’s ‘whole house’ protector. Protects from direct lightning strikes without damage. Costs about $1 per protected appliance. The superior solution is also the least expensive. But again, more numbers.

Low voltage on electronics is destructive because you observed? Nonsense. As taught even in primary school. Observation alone is junk science. Observation also “proved” a myth called spontaneous regeneration. Where are your hard facts and numbers?

As an engineer, you list each part destroyed by low voltage. You did not because you could not. You posted an ‘imperial decree’ because you only “observed”. Required numbers are from manufacturer datasheets. For example, the original 4000 series digital ICs for 5 volt operation could operate without damage at any voltage from 20 volts to -0.5 volts. The datasheet:
Texas Instruments 108514, DS datasheet pdf
Or SN74HCxx series digital electronics. Acceptable voltage is anywhere from -0.5 to 7 volts:
Texas Instruments 0jlueuzgy7xfh1cxw8ucuasqi1yy datasheet pdf

Why are low voltages not destructive according to the manufacturers? Well, consulted international design standards even from 1970. The entire low voltage section includes this phrase in all capital letters. “No Damage Region”. Standard even in 1970. Either the appliance works fine. Or it simply shuts off. “No Damage Region”.

Voltages so low that incandescent bulbs are at 50% intensity – and all electronics must work normally. One part of the design process is to learn how much lower that voltage goes before the appliance simply powers off – always without damage. Often, that voltage means a light bulb dims to 40% intensity. Electronics works normally – all internal DC voltages are rock solid - when bulbs dim that low. Or electronics simply power off. Those are the numbers. What honest posts must always include.

Low voltage does not harm electronics. Low voltage is potentially harmful to motorized appliances. Direct lightning strikes are routinely earthed without damage even to the protector. Plug-in protectors do not even claim protection in their numeric specs. Plug-in protectors even have a history of sometimes making appliance damage easier. And even have a fire risk. In every case, facts provided with the reasons why. Imperial decrees are how Limbaugh types insult the informed and educated. Please stop doing that. It is not nice, honest, or socially acceptable.

18

I did not forget anything. I provided information that I thought was relevant to the discussion. If I thought numbers would have been useful, I would have included them. Saying that I “forgot” comes off as a bit insulting. You may wish to choose your words a bit more carefully in the future, unless you truly meant the insult.

Are you claiming that the same sort of lighting systems employed in skyscrapers are available at Lowes and Home Depot? If so, please provide part numbers and manufacturers. I’d be interested in seeing that. The discussion here was about residential lightning protection.

And once again, claiming that I am using only “feelings” or that I am reciting “hearsay from English majors” comes off as more than a bit insulting. You may want to refrain from this sort of thing in the future.

I looked up the Cutler-Hammer surge protector you mentioned. On Lowe’s web site it only listed the maximum amperage. Lightning may be 50,000 amps (and can actually be higher), but it’s also several million volts. Looking at the amps alone isn’t what you want to do. 50,000 amps at 120 volts is a lot different than 50,000 amps at 2 million volts.

What you want to look at is the joule rating, not the amp rating. Lowes didn’t list the joule rating of the Cutler-Hammer, and I couldn’t find it through google either. I found a unit that was similarly rated for 50,000 amps and it had a joule rating of 1,000 joules. The highest joule rating I could find was a unit made by Sears, which was rated for 2,500 joules.

So, how many joules in a lightning bolt? Oh, about a billion. Do you see the problem here?

Once again, you come off with a tone that is extremely insulting and is based on erroneous assumptions about my thought process. Did you really intend to be that insulting and condescending?

Could not? Of course I can. Undervoltage on a computer hard drive can cause the platter to spin too slowly, resulting in a lack of sufficient air pressure to keep the head floating above the platter. This will cause the head to scrape across the drive surface, ruining it. Do you still claim that low voltage is completely harmless?

Need another example? Transistors are most efficient when they are completely on or completely off. In between (in the “forward active region”) they generate more heat. If you have a device that expects transistors to be completely on or off and you apply a low voltage that results in the transistors staying in their forward active region, they may overheat and become damaged.

Voltage regulation circuits which use a zener reference may not have enough voltage applied to them to reach the zener voltage. This will cause the voltage to be far out of regulation and could cause equipment to malfunction and break.

Low voltage could cause a relay to chatter excessively. Whatever is controlled by that relay may not be designed to tolerate its supply current being switched on and off rapidly and may fail.

Motors that aren’t driven by a high enough voltage may not spin, and their coils may overheat as a result.

I can provide many more examples as well, but I think that’s more than enough to prove the point.

With your condescending tone and attitude, I think you would be wise to reconsider what you think is socially acceptable. Just my 2 cents.

19

Let’s get one thing perfectly clear here. First, your title claims to be some kind of engineer. If true, then you always post supporting facts and numbers with each claim. You did not. When it comes to being condescending, you started it with ‘imperial decrees’. That insults me and any other educated people. I am assuming you did not understand that you were being condescending. Apparently you did not learn that recommendations must always include the reasons why. Otherwise the recommendation is akin to a scam.

I hope we can put an end to these sort of insults. Simply saying why - so that the opst can be based in honesty.

Now, back to science. Having now posted your reasons why says why you do not get it. For example, a million volts is everywhere in a connection from cloud the earth? That violates how electricity works. There can be a million volts between point A and B. That means that same million volts does not exist between B and C. Voltage only exists between two points. But in myths, that same million volts is in every location A B C D, etc. Your description of lightning explains why you do not understand how protection works.

You also do not understand joules. How do hundreds of joules in a protector absorb surges that are hundreds of thousands of joules. How does a power strip protector stop what three miles of sky could not? It does not claim any protection in its numeric specs - what the informed look at - the numbers. Joules - IOW where hundreds of thousands of joules dissipate. That is what you should be discussing.

Return to science we all learned in primary school. Lightning seeks earth ground. So lightning took a best path to earth via something more conductive than air. A wooden church steeple. Yes, wood is an electrical conductor.

But wood is not a very good electrical conductor. 20,000 amps through wood creates a very high voltage. 20,000 amps times a very high voltage is high power. Church steeple is destroyed. Excessive joules absorbed by wood.

Franklin put a lightning rod on the church steeple. Does a lightning rod provide protection? Of course not. A lightning rod simply connects to what does all protection - earth ground. Some foolishly argue pointed verse blunt rods. Trivial and irrelevant. What makes a lightning rod effective? Better earthing. What does the protection? What everyone forgets because they cannot see it? Earthing electrodes. How to make a lightning rod more effective? Enhance its earthing.

Now, the same 20,000 amps has a conductive wire and ground rods. 20,000 amps through wire and earth ground rod creates only a tiny voltage. 20,000 amps times a tiny voltage is tiny power. Near zero joules absorbed by the rod, wire, and church. No damage.

Protection is always about where energy dissipates. Always.

What is the connection from cloud to earth? Lightning to utility wires down the street is a direct strike to every household appliance. Damage occurs when a homeowner all but invites lightning inside. Once that energy is inside, then nothing can stop a destructive hunt for earth. Nothing can stop the hunt.

Protection means that energy does not enter. Lightning that finds earth via 2 x 4s causes house damage. Protection means a lightning rod. Lightning that finds earth via a computer, dishwasher, or furnace causes appliance damage. Protection means every incoming wire connects directly to earth at the service entrance. A short (ie ‘less than 10 feet’) connection via a ‘whole house’ protector.

Return to Franklin’s lightning rod. Where are those millions of volts? Where are those hundreds of thousands of joules? In the sky. In earth. Not in Franklin’s lightning system. Where are hundreds of thousand of joules when a ‘whole house’ protector connects 20,000 amps to earth? In the sky. In the earth. Not in the protector. And not destructively inside a house.

Recommended with prejudice and decades of experience is earthing and a ‘whole house’ protector. What is found in every building that can never suffer damage. As any honest post does, also said is why - with numbers. Provided is what everyone learned in elementary school science. And what you should know before recommending any protection system.

Responsible homeowners know that every wire inside every incoming cable must connect short (ie ‘less than 10 feet’) to earth before entering a building. Low impedance is a critically important number.

The concepts were taught in junior high science. To have knowledge means a hypothesis based in well proven science (with numbers). And then experimental evidence (more than just observation). Without both, knowledge does not exist. Without numbers, well, that is the definition of junk science. Knowledge from observation is classic junk science.

Well, 911 emergency operators do not remove their headsets and leave the room with each thunderstorm. Orange County FL was suffering lightning damage. So what was done to eliminate damage and danger? Orange County upgraded what does protection: earth ground. We know direct lightning strikes without damage is routine. But only when humans learn from their mistakes. And fix the earthing:
http://www.psihq.com/AllCopper.htm
Routine is it have direct lighting strikes without anyone even knowing the surge existed. Even a protector must remain undamaged. But that means learning the underlying science and numbers. The always required reasons why – which are provided here.

20

OK. Now this time you are providing reasons for your conclusion. Now let’s learn how all that hardware works. A power supply’s job it is to take a widely varying AC voltage. Convert it to rock solid DC. When your laptop sees voltage so low that light bulbs dim to 40% intensity - all DC voltages are perfect. When the laptop sees 265 volts - all DC voltages remain perfect. Where is this low voltage to chatter relays or crash a drive? Does not exist. Either the power is rock solid perfect. Or the system powers off.

Power supplies create DC voltages by converting AC power to high voltage (>300 volt) DC. Then converting that to high voltage radio waves. And eventually converting radio waves to low voltage DC. What happens when voltage drops too low? Does the transistor fail as you have speculated? Of course not. The transistors either create radio waves. Or the transistors remain off - no current - no damage. But again, either output voltage is rock solid perfect. Or the system powers off.

What does a disk drive see when power goes off. DC voltages slowly diminish. Voltages that are too low. So what does a disk drive computer do? Low voltage tells it to stop writing and to go into a power off condition. No damage. Either voltage is in spec. Or the disk drive assumes power has been turned off. Shuts down without damage. That is how disk drives worked even in the 1960s (even when disk drives used motor oil to move the heads).

How do all computers power off? All electronics go into brownout - low voltage - conditions. Eventually power drops to zero. No problem. Low voltage does not damage electronic hardware.

Voltage monitors and watchdog timers. More circuits to make voltage variations (and other problems) irrelevant. Read about them elsewhere. More solutions that make low voltages irrelevant. More solutions completely unknown to those so many others. Facts so that you can see through their lies and myths about low voltage damage.

Your reason for damage from low voltage this time says why. You did not know how disk drives and power supplies operate. Additional information provided. Facts that say why low voltages do not damage electronics. Now that you provided your ‘whys’, I can provide missing facts that say why they had you so deceived. And how to ‘don’t be fooled again’.