Helping people with computers... one answer at a time.

Problems with the power to your computer can translate into damage to your computer and data. I'll cover how much protection you might need.

I use a surge suppressor and an uninterruptible power supply (battery backup). I live in the southeastern US, and we're prone to summer thunder storms. My wife works for the State, and they never unplug their computers. I shut down and unplug everything from the wall socket when we have a close storm. What would your recommendation be? Or is that an unanswerable question unless you're here?

Oh, it may be unanswerable, but I won't let that stop me from taking a whack at it Smile.

I certainly can't give you a blanket yes/no answer, as the specifics of the situation really do play a large role in the solution. But I can tell you what I look at when I decide how far to take it.

Let me start by describing what I do - my situation is different than yours, but I think the process that leads me to my solution is a good example of the kinds of things that need to be taken into account.

I run one of my computers and some equipment through an uninterruptible power supply. I have something like eight computers here, but when the power goes out that UPS powers only the bare minimum needed to keep my network and internet connection up. That means one computer (a Linux box that runs my local DNS), two routers and a wireless access point. That's it.

"Having current and complete backups really are the closest thing to a silver bullet "

I do this to maximize the time that the UPS can keep this equipment running (probably an hour or two). It's designed to allow my laptops - which by definition have their own "battery backup" - to stay running and remain usable on the 'net. All the other machines (my desktop, my NAS, my whatever else) all go dark during a power outage. And they're all connected through inexpensive surge protectors to the wall socket.

It's all about risk management and tradeoffs.

I don't lose power often - perhaps once a year, maybe for an hour or two on average. When the power goes it typically goes down "cleanly" - meaning it's pretty close to turning off a switch.

And yet ... one year a power outage wasn't so clean. The power went down "roughly" (low voltage, high voltage, spikes and dips all before it finally went completely off) and in the process I lost one of my hard disks.

Yet I lost no data.

The tradeoff I made was to use various backup strategies - which would allow me to recover from this and many other types of failures - rather than investing in a larger UPS that might handle more of my machines.

As I said, I lost no data, and simply recovered/replaced the drive.

If my power were more frequently unstable, I might choose a different tradeoff. As it stands, losing a drive to a power hit every two or three years is less costly overall than a bigger UPS - as long as there's no data loss, that is. (And as I said, the tools protecting me from data loss are protecting me from a lot more than just power issues.)

I believe I've made a good tradeoff for my situation. I've thought it through, balancing the likelihood of various problems with the costs and inconveniences of recovering from those problems.

Your situation is different, as I said. You live in a lightning prone area and that means your risk tradeoffs will almost certainly be different than mine. Rather than the power simply going *off*, your risk might be the power suddenly spiking very, very high prior to going off. That is more likely to do damage.

In your shoes, I would at a minimum invest in a good surge protector. I know you said you have one, but I want to be clear it needs to be a good one. Not a cheap one such as those I can get away with here. You need one that's rated to handle things like lightning strikes. When you go searching, focus on objective evaluations and user comments, now liberally available on many online stores. A good surge protector is, in my mind, a 90% solution to your situation. (With one huge exception I'll mention below.)

My personal take is that your UPS may be optional. They can be expensive, and you need to trade that off against the risk of power going off and the risk of data loss happening if the power goes off. Of course the actual frequency of power problems plays a huge part in this decision as well.

In reality, once surges are taken out of the equation simply pulling the plug isn't as huge a risk. Don't get me wrong, it is a risk, and not something you want to have happen frequently, but it typically boils down to a data loss risk as opposed to an equipment damage risk. (And, yes, to cover all my bases equipment damage can of course also happen, but it's even less likely. When you just pull the plug the greater risk is to your data).

What I find interesting in all this is that there's more at stake here than just your computer. For example, you'll find that your telephone landline almost certainly goes through some kind of fuse or surge suppressor already. And of course we've all heard stories of TVs or microwave's being damaged by exceptionally close or direct lightning strikes. And that leads me to the next class of protection...

It's possible that larger installations you're mentioning don't need additional protection as much because they're already protected at some common source. This is well beyond my expertise, but I could theorize that a building or segments of a building are already protected with surge suppressors prior to the wall outlet. Some even have battery or generator backup as well.

Of course, it's also possible that none of that is in place and a good nearby lightning strike will render several electrical devices inoperative. I hope that they have good backups.

Finally, I let my own experience guide me as to what's really necessary. I've never unplugged a device in a thunderstorm, for example. But I might turn off computers not on my UPS if the power seems to be flickering and threatening to go out. But I have experienced so few problems I don't worry much about it.

My guess is that unless you frequently have lightning strikes nearby your home, your UPS and surge suppressor represent a good, solid solution for 99% of what you'll ever encounter. Of course things could happen - there are never any guarantees; it's all about probabilities and risk management.

Which leads me to the final and in my opinion the most important solution of all.

No matter what protection you have in place, backups are critical. If your hardware fails, or even if a minor power glitch causes a disk to become unreadable, a current backup can save you from catastrophic data loss. In fact, the number of scenarios where a backup can save you goes well beyond lightning strikes and power problems. Having current and complete backups really is the closest thing to a silver bullet when it comes to computing.

Article C4332 - June 3, 2010 « »

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Leo Leo A. Notenboom has been playing with computers since he was required to take a programming class in 1976. An 18 year career as a programmer at Microsoft soon followed. After "retiring" in 2001, Leo started Ask Leo! in 2003 as a place for answers to common computer and technical questions. More about Leo.

Not what you needed?

Pat Van Dusseldorp
June 8, 2010 9:31 AM

Living in the country where all power is over aerial lines tends to make us more prone to lightning. Several years ago I had lightning come in over the power. It literally blew apart one of the 600 amp service lines and blew a hole in the other along with many wall outlets and electronic devices. I thankfully had insurance but wanted more protection. The local power company insisted it was not their issue. I was however able to get them to allow my electrician to place a lightning arrestor between the meter and my main service box. I have had no problems since except for brown-outs which can also kill electronics. The power company has replaced the meter three times though.

Patrick Coppage
June 8, 2010 9:47 AM

Several years back a holy bolt struck the house next door. It popped ALL our breakers, toasted the tv, modem and computer and burned out all the light bulbs in use. A simple $39.95 surge protector isn't up to that blast of power.
You'll have to balance what protection you buy against what you stand to loose in worse-case scenerio.

June 8, 2010 10:05 AM

I live in the deep deep South, and am also subject to afternoon thunderstorms with attendant lightning strikes. My procedure when storms are close by is to save and close all apps, and shutdown via Apple menu, switch off the "surge protector", and unplug from same. When I leave home I do the same. When I go to bed I do the same.

It seems to me my computer is as well protected from lightning as I am. However you mention potential data loss as a result of unplugging.

Does anything described in my above stated procedure increase my risk of data loss, and if so why?

I understan the necessity of backup, but I see that as a somewhat separate issue.

Larry, Canton, Ohio
June 8, 2010 10:22 AM

I want to offer a couple addendums to Leo's writhing and the comments. Most surge suppressors use MOV's to do the actual work of controlling the surge. More than 95% of the time when an MOV fails it fails shorted. This means that if you have a suppressor, the last surge it controlled may have failed the MOV and you have no way of knowing it. In a higher lightning area suppressors should be changed routinely.
Secondly unplugging an item does not necessarily protect it. If the lightning strike is close the EMF from the bolt can produce a large current spike in any nearby coil of wire - like a transformer in a PC. I personally had 3 pieces of stereo equipment destroyed that were unplugged when a bolt hit a tree right next to my house.

June 8, 2010 10:34 AM

So much of the hype is nothing more than scare tactics to sell crap that really doesn't work. Remember the craze for awhile about the grounded wrist straps so your body static didn't blow out your entire CPU, RAM, and HD? Those $10 power strips that include a "surge protector" are NOT going to protect against a lightning strike. You're going to pay a healthy price for a REAL surge protector, and then you have to decide whether you're prone enough to such strikes to make it worth the cost. Most people are not that prone to begin with.

Battery backup is even more expensive. It might be a convenience to avoid rebooting in the case of a momentary interruption, it doesn't really do much good in an extended blackout since the battery will run down. Again, the infrequency and inconvenience really don't warrant the tremendous cost for someone who just uses his computer to check email, surf the internet, and play some games.

If money is no object, by all means, spend it on whatever makes you feel comfortable. Those Extended Service Plans they sell in stores when you buy a product are nothing more than a sucker bet, but on rare occasion, they turn out to be good for some individual. It's also what keeps the state lottery alive. (In case you haven't guessed, in 25 years I've used neither nor needed them. One day I MIGHT be wrong.)

Dave Markley
June 8, 2010 10:44 AM

I want to relate a story of what happened to me: A few years ago (I live in Southeast Florida) I lost about $4000 worth of electronics including my oven and refrigerator because of a hurricane, but not how you'd think! Before it hit, a 'feeder band' (Small wind surge before the actual storm) caused a powerline in my backyard to short out and send the full 220 volts through my whole house. All of my electronics were on relatively high-end surge protectors (which completely melted inside) and they all burn't up. Out of a 3-bedroom house, only one microwave, one alarm clock and my stovetop (not even the oven) survived! If a shorting 220 volt line could do this, a lightning strike containing millions of volts certainly can. Definately use a good quality surge protector and battery back-up whenever possible, but in a really bad storm unplug your electronics and don't forget the phone lines.
If you get a decent quality surge protector, make that sure you register it with the manufacturer as most of them will replace the value of what's connected to it if they do fail.

Mike Castro`
June 8, 2010 11:02 AM

I have my own electrinic security business, namely access control. My systems use very long runs of cable which tend to act like huge antennaes when lightning comes around. A mains powered access control system box costing about £900 will be reduced to a very black pile of soot like powder when it is hit by a minor bolt ( around 9000 volts ) and it will leap to the over end of a room when hit by a bigger one. Just being near a hit will fry lots of things. A surge protected fuse board with a telephone line protector will probably, but not always, save your laptop. Its only a few bucks/pounds/euro/yen, why take the chance. Get one with a master socket so everything shuts off when you turn your beloved computer off.

Chris Bryant
June 8, 2010 11:05 AM

I live in Colorado and have been struck twice, and been close 3 times. I have several external backup drives that I never connect to anything unless I am using them. I keep them away from phone and electrical outlets because lightning will "jump" out of an outlet and fry electronics, even if not physically connected.

You should invest in a whole house surge protector that is fuse based. I am a home builder and I use a Maxivolt MV100. It will stop a lightning strike that comes in from the power lines. Understand, that it must be placed between the strike entry point and your computer to stop the surge. If your phone or sat/cable lines come in from the opposite side of the home, and the lightning hits after the surge protector (i.e.: SAT dish), it can ride in on the phone/coax lines, which a surge protector can not stop. You can talk to Maxivolt or a local electrician for better incite into your situation, and you will need a licensed electrician to instal this type of unit. Even the house ground type and location can make a difference during a strike.

Those cheaper surge protectors that Leo discusses, probably are MOV's, which mean that every time they stop a minor surge, they become less able to stop the next one. They wear out, and the cheaper they are, the fewer surges they will stop, until they are completely useless. How do you know when they are used up, you can't.

I too, pull the plug, depending on how high my insurance deductible is and how much time I want to spend buying a new computer. Local electrical codes are designed to keep you alive and in no way guarantee that you will not have damage in the home. Lightning will do anything it darn well pleases, so be prepared.

Also, the more solar and wind (well known as "dirty power" in the industry) that we add to our power grids, the more unstable the power source will be, as it becomes increasingly difficult for electric companies to supply "clean" power. A surge protector can not protect against the coming brown outs, so get a good battery backup as well, IMHO.

June 8, 2010 11:47 AM

Go to Radio Shack and get an 8 foot copper lightening pole. Drive it into the ground and use grounding wire to attach it to your electric access box, cable access box (antenna), and phone access box (use 3 if more convenient). This will divert the high 'voltage' (path of least resistance).
Most surge protectors shut down when they get too much heat, not volts or amps.
A whole house surge protector will not stop internal house surges when 2-3 high power devices decide to turn on at the same time (A/C, Fridge, etc.).

June 8, 2010 12:49 PM

I can tell you from personal experience it an APC saved my system.

Lightening went over my house and struck a tree.
An earth shattering BOOM and my whole house shook.

The only problem I had was some messed up settings like my desktop settings etc...

Chris Bryant
June 8, 2010 1:12 PM

I wouldn't go to the Shack for rods. I would first check with a local electrician. If your house was built in the last 25 to 35 years or so, you should already be grounded correctly, "if" it was built according to code. Those rods help, but are not as good as a uffer ground (steel rebar into the foundation). You should be able to inspect your ground visually, somewhere near the meter box, making sure you have a good connection, etc. Our local codes do not allow copper rods anymore. They are not good during a strike, as I found out a few years ago.

If your power is falling off when appliances come on, which should be extremely rare in a newer home, you have either poor wiring (lines too long, too many outlets or electrical items on one circuit, or more than one large appliance on one circuit, or a poor source of electric coming from the power company. Most power companies are regulated by the PUC to keep the power within a certain range or big fines will come down upon them. Hence, my warning about wind and solar. If dirty power is being generated between their generator and your house, which they have little control over, you will still have problems, no matter what the fines. I lost a control board in my furnace and my electric double oven, (yes, they do use computer boards which are as sensitive as your computer mother board and just as big). But, good luck proving it was the Power Company. If you happen to loose your heat, check the 3amp fuse on your furnace mother board, it won't run without it.

I agree that a whole house unit will not stop internals, but that is not their purpose.

Nathaniel Gildersleeve
June 8, 2010 1:29 PM

You allude to it in the article, but protecting your modem may be important as well. Many surge suppressors have a port to run your phone line through. We had a lightning storm last summer that blew out my computer modem, the modem in my TIVO unit, and the credit card readers in all the local businesses.

Don Hopkins
June 8, 2010 2:55 PM

Both my neighbor and I have at separate times had to replace a motherboard as a result of lightening in the area (not direct hit) arriving via the RJ-45. Since then I have connected to the internet wirelessly through my router. In addition I protect the power with a UPS, although we have not had much of a problem with power.

Ron Sorensen
June 8, 2010 2:58 PM

Lightning is a constant problem here with computers. When there is a lightning storm,I turn off my computers (they have surge protectors) but mainly, I unplug the phone line to my modem. I lost a modem because of lightning once, and the phone line isnt protected. I would suggest unplugging the phone line to a computer during a lightning storm.

Rod Taylor
June 8, 2010 3:19 PM

I lost a modem once due to a lightning strike nearly a mile away. This was in spite of the fact that the phone service is underground.

One thing no one mentioned is having a three wire system, required for all new construction in our state; one wire ‘hot’, one wire for ground, and the third a safety ground. Notice that the power cord for most equipment has three prongs. Defeating the safety ground by using a three-to-two-prong adapter is not a good idea.

An UPS is always a good idea. One bright sunny day right in the middle of income tax preparation the power went off. Suddenly the computer which I was using was the only electronic device in the house working. I had time to save my work and shut it down, thus saving the few hours of time needed to finish the tax return and mail it on time.

Michael Horowitz
June 8, 2010 3:35 PM

@Chris: a good UPS can protect against brown-outs. APC uses the terms boost and trim to refer to boosting levels in a brown-out and trimming back levels that are a bit high but nowhere near a surge.

Also, a good UPS can indeed protect phone lines and coax. Also, Ethernet - I own quite a few that provide Ethernet protection. There are *lots* of models available.

Ilona Stewart
June 8, 2010 6:36 PM

My husband is a long-time electrician; we lost two dial-up modems to lightning but it didn't ruin the computer, as we are on a hill, and our part of Michigan has a low of power failures, and a brown out can burn out ALL your appliances with motors. We unplug our computers for COMPLETE protection.

Jon Frank
June 8, 2010 8:14 PM

In my job as a broadcasting engineer I have seen lighting damage on numerous occasions, but only once was it due to a direct lightning hit on a power line. If lighting strikes within 10 to 20 yards it can induce a massive electrical surges in to power lines, phone lines and TV cable lines that will destroy electronic equipment. Fiber lines are the only ones that are immune to lightning. As a rule, during the summer lightning season we always unplug our computers if lightning is in the area, or if we are going away for the weekend. Although surge protectors are reasonable protection from power company induced problems, a close lighting strike can be so massive that consumer surge protectors can fail to provide adequate protection.

Tony Lewis
June 9, 2010 5:26 AM

There is NO surge protector made that will protect your equipment from a lightning strike close to the house (power lines or phone/modem lines).
A close lightning strike will blow your surge protector AND you computer plugged into it.
If you are in a lightning prone area, BEST protection is shut down AND unplug PC, Modem etc.
Lightning CANNOT damage devices which are unplugged.

Neil C
June 10, 2010 7:28 AM

Leo's advice and all of the comments are right on. In addition, you can also get whole house protectors. In the scheme of things they are not even very expensive. In new contruction you ahould be able to get one for less than $500, although retrofitting is not always possible. Also, many local power companies offer whole house protection. They put a device on your line at the primary entry point. I pay Florida Power and Light $10/ month for this... I still use cheapo wall protectors and Back-up 3-2-1, but Idon't lose any sleep over this very real problem.

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