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Wednesday, August 10, 2005
  blackhole- Protecting against power surges

I’ve been spending some of my time off moving, which is to vacation what a state prison is to a five-star hotel.

Still, rooting through two decades’ worth of electronic detritus, trying figure out what to keep and what to throw out can be instructive.

Here’s one lesson I learned quickly: the devices that are supposed to protect your computer and other sensitive equipment against electronic damage might not be doing their job.

In fact, of the two dozen power strips with surge suppressors that I unearthed around our old house as we packed up for the move to a new one, only three still sported lights showing that their protective circuitry was active.

This is particularly important in places when thunderstorms, power outages and brownouts are all too common.

All can result in power surges that can fry the insides of your electronic equipment.

So let’s talk about how to keep that equipment safe.

First thing first

Nothing you can but in a store will protect your equipment from the awesome electrical power of lighting strike on your home or power lines nearby.

For that, you’ll need a whole-house lightning arrestor – an expensive addition that requires installation by an electrician.

If you live in an area on frequent lightning strikes, the best you can probably do is to unplug your computer and other sensitive gadgets while you’re away, or while you’re home if a thunderstorm is active in your area.

More likely sources of damage are brief increases in voltage – known as transients – that can result from the power returning after a blackout, of from the normal cycling of air conditioners, refrigerators or other appliances that use lots of energy.

Surge suppressors, most often found in power strips, deal with these surges using components known as metallic oxide varistors, or MOVs.

These devices divert excess voltage to the circuit’s ground wire while allowing normal voltage to pass through to your computer or another protected gadget.

A really high-voltage spike may melt everything inside the suppressor, leaving equipment on the downhill side unscathed, in which case the gadget has done its job.

But it’s more likely that a series of smaller surges will wear out the MOVs inside the power strip over time.

That’s why all but the cheapest units have indicator lights that tell you whether surge protection is available. Don’t confuse this with the light that tells you the power strip is switched on.

It’s easy to mistake one for the other – or just forget about the power strip entirely – as I did with far too many of mine.

That said, how do you know whether a surge suppressor is a good one? Price is one guide.

A US$7.95 power strip is fine for lamps and other devices that wont be harmed much by surges, but good components cost money.

Higher is better

The suppressor’s ability to absorb energy is measured in joules. Higher is better here – 500 joules or more for serious protection.

Another issue is reaction time – how fast the ground wire when it senses a surge.

Look for nanosecond (a millionth of a second) or less.

You don’t have to spend a fortune to get this kind of protection – US$20 to US$ 40 will usually do for a computer – and you can probably get away with less for other equipment.

Some suppressors also come with jacks for your phone and cahle lines, both of which can serve as conduits for surges.

Modems are especially susceptible to tiny fluctuations in current that many users never notice until they suddenly and unexplainably can’t connect to the Internet.

If you’re a dial-up internet user, it’s definetly worth the additional cost.

Power outage

Finally, even the best surge suppressor can’t protect your computer from harm during the true power outage.

If you lose electricity while your hard drive is writing, you could wind up with a scrambled disk. At he least, exiting from Microsoft Windows without a normal shutdown can put your PC at risk

That’s one reason to consider an uninterruptible power supply, or UPS. This is a battery backup that kicks in automatically when the regular power goes out, keeping your computer running until you have time to shut it down properly.

UPS units – which look like large, heavy bricks –typically have six or eight outlets.

Half will usually be backed up by batteries, while the reminder will be protected against surges and spikes only.

Starting at US$75 or so, battery backups are usually priced by how much juice they provide. The cheapest units ay only keep PC running for five to 10 minutes – long enough to perform proper shutdown.

More expensive units can keep a system running for an hour or more.
The most efficient way to use a UPS is to plug the minimum amount of equipment into it – meaning your PC and monitor.

Leave printers (particularly laser printers – plugged into protected outlets and leave as much juice for your PC as you can.

Once do you have your critically essential equipment protected, do what I didn’t. check your surge suppressors from time to time to make sure they’re still working.

Replacing them could save you money and grief down the road. – LAT-WP

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