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Re: ups (uninterrupted power supply) questions?

To: "shop-talk" <shop-talk@autox.team.net>
Subject: Re: ups (uninterrupted power supply) questions?
From: "John T. Blair" <jblair1948@cox.net>
Date: Sun, 20 Mar 2005 09:27:33 -0500
At 12:14 AM 3/20/2005 -0500, Scott Hall wrote:

>just lost another answering machine, vcr and cable modem.  I just got 
>two new monitors and I'd hate to lose them, too.  the i.s.c. guy at the 
>wife's office recommended a u.p.s. as sort of un uber-surge protector, 
>and it'd give me a chance to shut off the computer as well when the 
>power went out.  he's a nice guy and all, but I thought I'd ask anyway...

Scott,

You don't say what you lost this equipment to.  There are 2 primiary causes,
surges (and or lags) from the electric company, then catastrophic surges
like lightening.

Surge protectors will handle a couple of hundred volts from a surge from
the power company, but can't handle a lightening strike.

For that matter, neither can the power supply in a UPS.

Lightening can effect you equipment in several ways:

1. A direct hight - to either power lines, cable lines, or telephone lines.
   a. A hit to a power line will/can take out multiple pieces of 
      equipment.
   b. A hit to the cable line will/can only take out equipment connected to
      the the cable - ie a tv or cable modem.
   c. A hit to the telephone line will/can take out equipment connected to 
      the phone line - TEVO, computer - via a dialup connection to the phone
      line, and cordless phones.

2. A close strike. A strike in your yard (or a neighbors) can have enough
   energy to fry equipment but more of an emp.  If your computer is up and
   running, it can also impart energy the the heads of your harddrive and
   erase data on your drive.

If you problem is from the electric company, then I think you have some
recourse to them to replace your equipment.  If it's from lightening
then you'll need to talk to God.  

In the case of lightening, the best defense is a good offence.  You will have
to make some judgement calls:

a. How important is it that the piece of equipment be up during the storm?
b. How expensive is the equipment to replace?
c. What is your cost for down time.

The answers to these questions will be different for a home or a business.
As a ham radio operator, we have several local repeaters - isolated radio
stations that will repeat our transmissions giving us a larger range.  These
are usually left on line during bad weather to allow for emergency 
communications.  However, when we do, and we have taken lightenstrikes, it
is very expensive, both the receivers and transmitter, and the computer 
controllers usually get fried, not to mention the coax of antenna feed 
cable.  That's the cost of doing business, and the members have to pay to
replace it.

As I said above "the best defense is a good offence", for a home you might 
want to think about a couple of things.

1. For Power - unplug and expensive or sensative equipment - like computers, 
   TVs, and Sterios.

   a. Use power strips where ever you can so you don't have to unplug a lot
      of plugs.  Pulling the plug from the power strip will disconnect all
      equipment that is plugged into it.

2. Disconnect equipment from telephone lines, ie you computer if you have a
   dial up connection, or a fax connected to the computer.

3. Disconnect equipment from your cable.  You might want to think about how
   that is installed.  You might want to have a single point of entry for the
   cable.  Then at a convient point have a splitter to send the signal to
   different rooms.  That way you can disconnect 1 connection to remove all
   equipment from the cable lines.
  
Yes this is inconvient.  But so is paying for your car insurance.  But it's
really the only insurance.

I turn off and disconnect my computers when ever we get a lightening storm.
During the time of year when we have a lot of storms, I keep the equipment
off and disconnected unless I want to use them.  That way, I don't have to
worry, if I'm at work and a storm comes up.

In closing, even lightening arrestors aren't 100% safe.  If lightening can
jump a couple of miles from the cloud to the ground, what's a switch with
only fractions of an inch seperation going to do?

Also many surge protectors, if hit by a big surge, are fried to protect your
eqiupment.  Therefore, need to be replaced after use - much like a fuse.

John


John T. Blair  WA4OHZ     email:  jblair1948@cox.net
Va. Beach, Va             (eBay id: zebra48-1)
Phone:  (757) 495-8229

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