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From: shap@sfsup.UUCP
Newsgroups: comp.sys.mac
Subject: Re: Surge Suppressors
Message-ID: <1016@sfsup.UUCP>
Date: Fri, 9-Jan-87 22:20:40 EST
Article-I.D.: sfsup.1016
Posted: Fri Jan  9 22:20:40 1987
Date-Received: Sun, 11-Jan-87 07:08:31 EST
References: <1094@Shasta.STANFORD.EDU>
Organization: AT&T-IS, Summit N.J. USA
Lines: 58
Summary: Surge suppressors are essential

In article <1094@Shasta.STANFORD.EDU>, hans@Shasta.STANFORD.EDU (Hans Mulder) writes:
> 
> Recently I had a discussion at a local computer store about power surges
> and other uncleanliness on the wall(AC) power
> They claimed that some of my problems with my harddisk (4 defects in 6 months)
> were due to dirty power and that I should immediately buy a surge suppressor.
> They basically claimed that the wall power is so bad that it can destroy
> power supplies (and other parts of a computer)....

Indeed wall power is horrible, and its quality depends a lot on what block
you are on and which power trunk and the phase of the moon and the quality
of your local power station and the current price of tea.

It is possible for electricity to do oddball things, like blowing out
little used portions of, say, a ROM. You won't konw until you need it.
It is also easy for an unprotected computer to be turned into so much
charred plastic and metal by a vagrant electrical storm. There have been
several such tales of woe on the net over the years.

The same holds for VCR's, Televisions, and the like.

Manufacturers do not tend to include this stuff by default because it
costs money, and sites with more than a few machines often have their own
power conditioning, and don't want to pay the extra money. Also, it is more
profitable to let you replace your PC.

As to the warrantee, electrical damage comes under acts of God, and usually
warrantees do *not* cover these.

There are two sorts of protection you need. The first is from spikes, which
are instantaneous transitions of voltage on your power line which can go as
high as five times the line's rating. These little jiggles can quite
contentedly blow away silicon. The second is surges, which are of longer
duration, though usually not as high. These can be caused by the time lag
between the grocery down the street's industrial freezer kicking in and the
power company putting more power on the net. It is a feedback process, so
when the unit kicks out there will be too much power for a while. Either
direction is a potential problem.

Some dealers will tell you that these are the same thing. They are not.
Electrically they have different properties and are prevented by slightly
different circuitry (mainly, some capacitor and resistor values change).

You probably want a unit with a circuit-breaker rather than a fuse. They
cost a bit more, but it pays off the first time you would have needed
to replace the power protection. I have had occasion to be thankful....

As to brands, I use the Apple/Lemon/Orange/etc.. series, which many dealers
carry. I am sorry that I do not recall the manufacturer.

It is about the cheapest insurance policy you can by. Not protecting your
3,000 dollars worth of computer equipment with a $30 surge suppressor is
just plain foolish.

Hope that helps a bit.

Jon Shapiro
AT&T Information Systems