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Protecting equipment from power outages can be done with a large battery called an Uninterruptible Power Supply.

We recently had a power outage. When the power came back on, my computer has been acting really bad - slow, shutting off and on. I had it on a standard power surge protector (the Home Depot style). There were also several TVs in the neighborhood which stopped working.

A) Is a standard power surge protector good enough?

B) Do you know if the power companies are liable for these power surges in any way? I live in California.

In this excerpt from "Answercast #77, I look at ways to protect computers and other equipment from fluctuations in power supply.

Protecting equipment from power outages

Well, clearly a power surge protector didn't help you in this case.

It's important to realize what a power surge protector does. It protects from exactly what the name implies - a surge of power. If the voltage for example (which would normally be 120 volts here in the United States) happened to shoot up to 160 or 240 or one of the other higher voltages, the surge protector should protect your equipment by shutting down. Basically, the fuse should trip or something else should cause the power to be turned off to your equipment completely and before any damage occurs.

Power fluctuations

The problem is that that is only one type of problem that can happen to your power.

  • The power could go too low.

  • It could go on and off rapidly

That is actually not that uncommon - like in our case here up in Washington. When trees fall on our power lines, the power will flicker. That too can cause problems for your computer (and in some cases) can damage the computer.

Protecting from power disruptions

What you need of course depends exactly on where you live and what kind of power issues you might run into.

Here (as I said, in Washington), the power fluctuations that we've had have yet to cause me any concern for any of my computers. Yes, they'll reboot occasionally if the power flickers substantially, but for the most part, there's been no loss of equipment or damage due to that.

I'm taking a risk (it's a calculated risk) by plugging directly into the power through surge protectors, but still plugging directly into the power supplied by the power company.

If I wanted to protect myself more completely (and this would apply if what you experienced is something that happens often)... is to run your power through what's called an "Uninterruptable Power Supply" or UPS.

Backup power

What a UPS is is basically a big battery. They actually use the same technology that you'll find in an automobile battery - a sealed automobile battery, but usually much smaller. You'll find out that they're very heavy. That's because the batteries themselves contain a fair amount of lead, which is very heavy.

What happens is you plug in the UPS into your power company supplied power, and then you plug your equipment into the UPS. If the power flickers coming in, or if the power goes away, the UPS automatically and almost instantaneously keeps the power running off of the battery - so your equipment actually doesn't notice the flicker. It doesn't notice the power going away.

How long your equipment can keep running off only that UPS battery depends on the size of the battery and how much equipment you're trying to run off of it.

I have a UPS in my home. It is not necessarily to protect any equipment from power surges or power problems. It is to keep my network running for a while in the event of a power outage. If I lose power here (which happens maybe once a year and varies from a few minutes to a at worst a couple of days)... when that happens, my network will keep running. I believe it will run upwards for an hour or two, based on the equipment that I've got plugged into the UPS and the size of the UPS itself.

What that allows me to do, of course, is use my laptops (which are themselves running off their own internal batteries) and continue to connect to the internet long enough to... I don't know get; an important email out; shut down some service that I might otherwise not need; let some people know that we're out of power; whatever.

It gives me an opportunity to clean things up on the internet should I need to.

UPS: Un-interruptible Power Supply

Like I said, an uninterruptible power supply would probably solve the problem that you ran into.

They're not cheap. I think you're talking probably $100 at least for the smallest one. But they can in fact protect your computer from a wide variety of power problems. You might consider them good insurance, especially if you live in a place where this could happen from time to time.

Power company liability

Now, as to the other question, "Is the power company liable?"

I'm not a lawyer; this is not legal advice. I really don't know. That being said, I've never heard of a power company being liable. I would assume that it would depend on exactly why the power went out. If it was intentional or malicious on the power company's case then... maybe.

But for the most part? Like here, if a truck drives into a power station, or a tree falls onto a power line and breaks it? No. The power company is not liable for that and they're not going to be liable for any damage that results. It really is on you to protect your equipment.

(Transcript lightly edited for readability.)

Article C6113 - December 9, 2012 « »

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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.

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3 Comments
Dan
December 11, 2012 9:54 AM

Might be something the home insurance could take care of, but size of deductable might not make it worth it. When we had a lightning strike that took out a lot of my electronics - insurance covered that. Something you would have to ask.

Peter
December 11, 2012 9:03 PM

Hi folks.

Great answer Leo, for beginners. The fact of the matter is that there are two types of problems affecting power. Effects on current (amperage) and effects on voltage (volts). The nature of the problems can be sags (i.e. less than needed) or surges (more than needed). Generally surges are called spikes if they are very short duration (i.e.

UPS's are all fine and dandy, but they are designed to a specification that basically says if the power line disturbance exceeds my spec, then I can't handle it - I hope the load (computer) can! When lightning hits a power line, about 5 times/year in Ontario as per studies, you are likely facing a "spike" in current. Your UPS better be good! Lightning strikes have been measured to have caused as much as a 20000% disturbance in powerline characteristics, though this is quite rare. One can normally expect most, not all, disturbances not to exceed 1000%, and for a short duration. Most UPS's are of an electronic design, and those that the average consumer might purchase, likely handle only the weakest of disturbances before passing it on to the load. The logic to these UPS's is that if the disturbance exceeds my specs, I must protect myself because I'm electronic, so load, I hope you are ready!

There is a technology known as a "mechanical" UPS which can handle just about anything that could be thrown at it, but the cost is certainly not something the average consumer could afford, even if one could put up with the noise.

What I do is simple. I watch the weather reports. If "lightning" storms are imminent, I remove the power cord from the outlet. I do this for my computers, my answering machine, my TV, i.e. all the "elecronic" gadgets. When I had a "land line" modem to drive my internet service, I disconnected the phone jack. Most people don't realize the land line phone system has its own power source (not your home) that is grounded and provides the perfect path for that stray electricity coming down the power line straight through your computer system and modem because it was too much for the UPS to handle! In most cases you are lucky, because it only killed the modem and not the computer! If it didn't have that path to ground, well what was that weird problem you were having?

I use a power surge bar to avoid something called dirty electricity - very small sags and surges - that occur when electrical motors (fridge, washer, dryer) start or heating elements (oven, hair dryer) kick in. These can cause problems over time through wear and tear on a system.

I can see where a person like Leo might take steps to assure a power source, including redundant UPS's (preferable mechanical) with redundant short term battery backup (15 to 30 minutes) and redundant motor generators to assure the operation of his business, but your average user - I think not!

Cheers

Tony M.
December 20, 2012 4:07 PM

Yes, another great Ask Leo article. I don't have any laptops, so when it comes to having an UPS, I would never go without one. To my thinking, next to doing regular system backups, the next-best thing you can do to protect your system AND your hard-disk-stored data is to use an UPS.

Just as with everything else, it depends how much you value your equipment and the information you store on it.

And just like with doing backups, using an UPS feels like a waste of time and money ... UNTIL your power is interrupted, which is the very moment you'll instantly feel the satisfaction of knowing your hardware, open documents, and data integrity have all been preserved by having the opportunity to save your open documents and perform an orderly shutdown.

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