Re: House Power Failures and Mac

On Sun, 10 Feb 2008 08:28:38 -0500, Dudley Henriques wrote
(in article <x5qdnac6O9KaYTPanZ2dnUVZ_rignZ2d@xxxxxxx>):

I guess I'm a normal home user with an IMac. I've been thinking about
how I use the computer vs a potential house power failure and how that
might effect the computer if it's on or sleeping when that happens.

My system is up for about 18 hours a day; either in use, on the screen
saver; or in sleep mode. Sometimes when we go out I'll shut it down in
case of a Thunderstorm, but otherwise it's up and running.

I let it sleep all night usually and it's here I'm worried about a power
failure and what that might do to the Mac.


Obviously I could purchase a battery power supply backup system but
that's a fairly large expense for a home user.

Can you let me in on how some of you deal with this issue?

One thing I'd like to know is how my Mac would suffer or not suffer in
the event of a house power failure. My PC with Windows was a mess when
this happened (twice) but so far I've been lucky with the IMac.

If I do get nailed, what's the prospect for damage and are there built
in utilities in my OSX that I can run after a failure to help restore
things back to normal?

How do you other home users deal with this?????

Thanks much


Gat a UPS, as some others have said.

Note: the cheaper battery-backed systems on the market are really _SPS_
systems, _Standby_ Power Systems, not _UPS_ systems, _Uniterruptable_ Power
Systems. In a SPS, what you have is a box which contains surge protection, an
AC/DC converter, a battery, a DC/AC converter, and a very fast switch. The
battery is trickle-charged by power from the mains via the AC/DC converter
and the surge protection. In the event of a power failure, the very fast
switch cuts off the mains connection and cuts on the DC/AC converter. It
happens so quickly that most systems won't notice the fact that they
momentarily lost power. However, SPS systems give you only the protection
that a good surge protector gives you, plus battery backup. This will not do
much against large surges, which will blow past your surge protector. Also,
most surge protectors are built around MOVs, metal oxide varistors, which
take a hit each time they stop a surge and which die after they take enough
hits. Depending on the quality of electrical service in your area, a surge
protector's MOVs might last 3 years. Or they might last 18 months. Or less.
As a SPS is a surge protector...

A UPS is a box with surge protection, an AC/DC converter, a battery, and a
DC/AC converter... but no switch. What happens is that power comes in, goes
to the AC/DC converter after being filtered by the surge protector, feeds the
battery, which feeds the DC/AC converter, which feeds your system. The
battery is being continuously charged and is continuously feeding power. This
means that after a while you'll have to exchange the battery. Higher-end
UPSes also allow you to replace the surge protection. In any case, nothing
can get to your system without first going past the AC/DC converter and the
battery. Typically you'll end up with a dead UPS and no power on your system,
but you can replace the UPS and your system should still be operational.

Note that if you put a surge protector between the UPS and the wall socket
you'll protect the surge protection on the UPS. You'll have to replace the
surge protector every ever so often, but that'll be cheaper than replacing
the UPS if you don't have one of those which allows you to replace the
built-in surge protection periodically.

I live in Florida. Lots of thunderstorms. I used to live in Jamaica and St.
Lucia. Lots of thunderstorms. I lost a lot of equipment due to thunderstorms
and other system problems before I started using UPSes. Since then, I've lost
several UPSes, but nothing else. And that includes the time that I came into
the office in Jamaica one morning to find that my large Liebert 250 kVA
central-model UPS was smoking... Central-model UPSes work by being plugged
into the electrical system at the main panel. Main power, 220 volt or 400
volt three-phase, depending on the size of the UPS, is fed to the UPS, and it
then feeds a particular circuit. Users plug equipment into wall sockets using
that circuit. Yes, we needed 250 kVA, we had a _lot_ of systems installed. We
had a contract with the local Liebert dealer, who came out and replaced the
dead machine in under 3 hours. They blamed it on a major surge due to a
lightening strike close aboard. If that UPS had not been present, I would
have lost some/most/all of my computer equipment.

YMMV. But I use UPSes at home and at the office, and plan to continue to use
'em so long as the power gird is less than perfect.

--
email to oshea dot j dot j at gmail dot com.

.

Relevant Pages

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