Effective surge and spike protection for computers?

[Cameron Dorrough]

Hi,

I'm looking for information on the best ways to protect my computers from
power problems. I've got 2 questions:

1)I recently lost a network card to a lightening strike. My computer's power
was connected to one of those $50 powerstrips and it was undamaged. The
network card was connected to a 10 metre cat5 network cable that runs under
the house on the underside of the floorboards to the switch in the other
room. None of the other computers or networking equipment were damaged.

Why would my network card be the only component damaged? I thought at first
it was because it was the only part not connected to the surge protector.
But if that was so why wasn't anything in the other room (including the
cable modem - the only external connection on the network) damaged? Could
it be because the power board simply shunted the surge voltage and it went
into the computer and down the net cable as a path of least resistance to
ground?

I'll leave this bit for the experts..

2) As the great Australian summer approaches with lightning storms, strong
winds and even bushfires which cause sustained power brownouts and surges
as they burn under high-voltage lines I'm looking for the best way to
protect my computers and network.

I've read in a lot of newsgroups that plugin surge protectors are useless as
they have offer no real earth ground - at least not one that is lower
reistance than the computer or device itself.
What do people have to say about this?
Even if this is so are they worthwhile for protecting against brown outs and
subsequent surges caused by non-lightning events such as wind blowing
powerlines over or bushfires burning under them? (a very real problem in
this part of Sydney during bushfire season)

Tim, plug-in surge protectors shunt high voltage spikes to earth well
enough - but the let-through voltage can still rise high enough to destroy
sensitive electronics (like computers - especially newer computers).

The only real, practical, way to protect your computer against brownouts,
surges and the like is to install a *quality* uninterruptible power supply
(UPS). There are three types to choose from:

1. "Off-line" - the cheapies you find in K-Mart, Dick Smith and Tandy.
These units have little or no real surge protection (you blow up the UPS,
not the computer it's attached to) and only switch to battery when the mains
fails.

2. "Line Interactive" - an off-line unit with a few more features. Some
surge protection and switching to battery anytime the mains goes much above
or below the correct output voltage.

3. "On-line" - works off the battery all the time. The mains supply simply
keeps the battery charged. These units are more expensive mainly because
the batteries must be larger and be rated for constant use. Surge
protection is guaranteed by the complete isolation of your computer from the
incoming mains.

As with most things, you get what you pay for. To protect a PC, a
line-interactive or true on-line UPS is the only way to go. The better
brands include Powerware, MGE, APC.. Cheaper units like Sola have less
surge protection and *will* need to be replaced after a decent surge.

In this country, everyone with an expensive computer setup should be
connected to a UPS. You don't need a big one either - A$400 will get you a
Powerware 5115 500VA one - more than enough for one PC.

Hope this helps,
Cameron

 

[Tim Edwards]

Hi,

I'm looking for information on the best ways to protect my computers from
power problems. I've got 2 questions:

1)I recently lost a network card to a lightening strike. My computer's power
was connected to one of those $50 powerstrips and it was undamaged. The
network card was connected to a 10 metre cat5 network cable that runs under
the house on the underside of the floorboards to the switch in the other
room. None of the other computers or networking equipment were damaged.

Why would my network card be the only component damaged? I thought at first
it was because it was the only part not connected to the surge protector.
But if that was so why wasn't anything in the other room (including the
cable modem - the only external connection on the network) damaged? Could
it be because the power board simply shunted the surge voltage and it went
into the computer and down the net cable as a path of least resistance to
ground?

2) As the great Australian summer approaches with lightning storms, strong
winds and even bushfires which cause sustained power brownouts and surges
as they burn under high-voltage lines I'm looking for the best way to
protect my computers and network.

I've read in a lot of newsgroups that plugin surge protectors are useless as
they have offer no real earth ground - at least not one that is lower
reistance than the computer or device itself.
What do people have to say about this?
Even if this is so are they worthwhile for protecting against brown outs and
subsequent surges caused by non-lightning events such as wind blowing
powerlines over or bushfires burning under them? (a very real problem in
this part of Sydney during bushfire season)

Thanks

Tim Edwards