Effective surge and spike protection for computers?

[SQLit]

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

The correct method of protection for surges and spikes is done zones. The
first is network class, this is the utilities responsibility. They have some
but it is set to protect their equipment. The next zone is at the service.
You can buy these from Square D, Cutler-Hammer and other manufactures. I
have the Ch one on my home. It connects to two poles of a CB that does not
turn off. I happened to have a spare 2 pole breaker so I used that. This
device has a place to plug in your cable TV and phone. The protector is in
series with those services. Last zone is the plug strip.
Each zone has a let through voltage and if you read the specs on the one you
have you will be amazed. Something like 330 volts is the let through on
mine.

Lightning is an interesting subject. As an example only, Cows die from
lightning not because they are hit it is because their feet are more than 1
meter apart. Has to do with different paths and where the lightning strikes.
My guess is that your Ethernet line was in the right place at the wrong
time. Put the Ethernet wire in metal conduit, that is grounded on both ends
and you may not have any more problems. I have heard of some enet cable that
is grounded, have never seen it nor have I installed any. The only other
idea I have is to get a plug/surge strip with enet connections and run the
enet through the plug/surge strip. I have never seen any of these, just
telephone and cable.
just my quick thoughts I am sure others will have better ideas

 

[w_tom]

Summary of how surges damage and what a surge protector
does:
"Opinions on Surge Protectors?" on 7 Jul 2003 in the
newsgroup alt.certification.a-plus or
http://tinyurl.com/l3m9

More technical details:
"Power Surge" on 29 Sept 2003 in the newsgroup
alt.comp.hardware or
http://tinyurl.com/p1rk

First, it is wire impedance to earth; not resistance.
Impedance is why the earth ground connection must be less than
3 meters.

Second, determine the complete circuit path of a destructive
transient. That plug-in protector could have completed a path
to earth ground, destructively, via the computer. Surges must
be earthed before they enter the building. Once inside the
building, a destructive surge has too many paths to earth and
too many appliances to damage.

Also was that incoming cable earthed at the same single
point that everything else is earthed - including AC
electric. The all so important single point earth ground.

Third, brownouts are not hardware destructive events. In
fact, every time a computer or TV or whatever powers off, it
suffers a brownout as the electrolytic capacitors slowly
discharge. Incandescent light bulbs can be glowing at less
than 40% intensity and still all properly built computers must
work just fine - as demanded by industry specs. If voltage
goes even lower, then computer simply shuts down - without
damage.

Fourth, for about the price of one or two ineffective
plug-in protectors, you could have protected everything with a
'whole house' protector. That would be about $1 per protected
appliance verses the $50 spent for ineffective protection.

Fifth, surge protectors do nothing for blackouts, brownouts,
harmonics, or noise. They only do one thing. They short
circuit the wires to earth ground only during the surge. No
less than 3 meter connection to earth ground? Then the
adjacent surge protector only gives that surge more paths to
find earth, destructively via computer.

For data protection from brownouts: that is what a UPS is
for. Different function located in a different location.
Plug-in UPS is for blackouts and brownouts; does not address
the other three problems. Building wide UPS typically address
all five power problems.

 

[BUSHBADEE]

Get a UPS.
I run all my equipment on a UPS.
That means if the voltage gets low or cuts out, my equipment continues to work
and the UPS starts singing me an annoying song to warn me.
I then shut the equipment off.
The Supply will carry the equipment for about 1/2 hour.
this allows for an orderly shutdown.

Most supplies nowdays even have the software and capability to shut down your
system.
..
..
I DO NOT FOLLOW MANY OF THESE NEWS GROUPS
To answere me address mail to
(e-mail address removed)

 

[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

 

[Lane Lewis]

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

More then likely the surge came from the other computers down the cat5 and
into your net card where it found an easy path to ground.

You need a whole house surge arrestor that is installed properly by a
licensed electrician. Ask for a Square D brand.

Use the powerstrips also but buy the best you can find and replace the old
ones.

Lane

 

[Mark or Sue]

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?

Interconnected computer equipment should all be on the same power strip, or
do not use parallel "shunt" type suppressors (which 99% are). During a big
spike, a shunt mode discharges the surge to ground. Each device doing this
can end up with its ground potential quite a bit different from the others.
If there are paths between these devices (like a cat5 or coax cable), the
voltage surge can fry the line drivers. Lightning can do weird things, and
no matter what you do sometimes you still lose.

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)

I'd suggest the following:
Verify your electrical service is well grounded -- multiple rods and
preferably a buried metal pipe too.
Install a parallel "shunt" type surge suppressor at the electrical service
entrance.
Consider only series type surge suppressors for the computer and network
equipment (or a real UPS). Read more here:
http://www.surgeprotect.com/brickwall.html?source=businesscom

Consider changing all interfaces between equipment not on the same outlet or
power strip to fiber optics.

 

[ehsjr]

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.

They are not useless. They clamp the voltage that the plugged in
device "sees" across hot-neutral and hot-ground at the equipment
plug to a level that is safe for that equipment. They can be less
effective when the plugged in equipment has another path to ground
besides the ground prong on its line cord. Such may be the case
when you network - there may be a path via the network cable
(through something connected to it) to ground. If the network
is connected to the phone lines, it can find a path that way.
(And a surge can come in on the phone wires, too.)

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)

They won't help for brown outs.

 

[Tim Edwards]

Thanks to everyone who replied.

If the power strip is to blame for sending a surge down the network cable
would it be because it is too far from an earth ground? It is on a normal 3
prong plug but the room that its in is more than 3 metres from the metre
box. Are there other points, besides the metre box, where the 3rd wire
reaches earth ground in a typical house wiring setup?

Also does anyone have any suggestions for a good whole-house surge protector
- good brands? expected pricing? any that can be installed DIY? And does
anyone know of any companies here in Sydney Australia who do installations
or sell these things?

Thanks

Tim Edwards

 

[w_tom]

Essential to earthing a surge is the single point earth
ground. Earthing at multiple points can mean a surge uses
household appliances to destructively obtain that other earth
ground rod. For example, if earth that a surge seeks is to
the east, then a surge that strikes western side utility wires
or even west side earth can travel into the the house via west
side utility wire or via west side earth ground rod, then pass
destructively through household appliances, then enter earth
via the east side ground rod.

Earthing is a concept called equipotential. One way to
create this equipotential is a single point earth ground. To
make it more effective, the more serious buildings connect
that single point ground also to a big loop that surrounds the
building, or to Ufer ground in the foundation footings, or
wire mesh embedded in the concrete floor - all connected to
that single point ground. The only connection between
interior grounds to that earth ground is a single point.

BTW, computer motherboards should be attached to chassis
using the same principle (only one conductive standoff) for
same electrical reasons.

Yes, the connection from a wire to earth ground must be less
than three meters which is why receptacle grounds are not
earth grounds. Those receptacle grounds are safety grounds -
to connect to breaker box single point safety ground. Breaker
box safety ground does connect to earth ground. But they are
distinctly different grounds, wired together, so that the same
grounding wires accomplish multiple solutions.

Some examples of 'whole house' protectors:
AC electric
http://www.keison.co.uk/furse/furse06.htm
Telephone
http://www.one.co.uk/catalogue/telebyte/LightSurgeProtect/22PX.HTM
http://www.keison.co.uk/furse/furse11.htm
Network
http://www.keison.co.uk/furse/furse08.htm
http://www.keison.co.uk/furse/furse07.htm
http://www.keison.co.uk/furse/furse19.htm

 

[Richard Freeman]

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?

how far/close was the strike ? how is your house wired ? not really enough
info provided to tell however a number of possibilities spring to mind not
the least being that the cable picked up an induced voltage and the switch
rode out the strike whereas the PC being earthed could not.

In fact do you live in the north of Sydney? and did this happen about two
(or was it three ?) weekends ago - I had a near strike (It hit the 11KV
power lines 50 Meters down the road) a couple of weekends ago - Nothing
damaged might I add although the oven clock, my Clock radio and the burglar
alarm needed to be reset - And no I have no Surge protection as I have seen
too many charred and scorched Surge arrestors to have any faith in them.

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.

if desperate run a UPS

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?

You have probably been reading the ravings of w_tom who probably knows less
about lightning protection than you do and certainly nothing about MEN mains
as used in Australia (and many other countries including the USA). In point
of fact a plug in surge arrestor can offer better protection in the event of
a near strike than w_toms 'whole house protection' due to the simple fact
that it offers surge protection at the device being protected rather than
via goodness knows how many meters of wire.

A little appreciated fact that w_tom would have you ignore is that MEN power
distribution generally provides pretty good protection against Lightning (he
pretends any effects like this is due to Lightning being a 'low energy
event' and with any luck he will go and fly a kite during a thunderstorm in
an attempt to prove his point) and in fact most Lightning damage comes in
via Paths other than AC mains ( as you have discovered with your LAN cable)
most commonly Lightning damage comes in via phone and data lines ( usually
pausing briefly to incinerate any Surge protection on its way).

in the event of a direct or near strike pretty well no Surge protection is
going to be effective unless you live in a metal box.

Even if this is so are they worthwhile for protecting against brown outs

The only protection here is a UPS

and
subsequent surges caused by non-lightning events such as wind blowing
powerlines over

sustained protection against 11 or 33KV is a big ask - not many surge
arrestors offer significantly more protection than what your equipment
already has built in.

or bushfires burning under them? (a very real problem in
this part of Sydney during bushfire season)

Typically causes brown outs so back to the UPS

 

[Richard Freeman]

Firstly current list of questions regarding lies/foolish statements that
w_tom has made but not explained :

Tell me again tom what a Thermal Fuse is.

Tell me the fairy tale again about how Lightning is a 'Low energy event'

Identify the 'direct connection between AC mains and the Integrated circuits
in a modern modem' for me.

explain how 0.6mm diameter single strand copper wire has a lower impedance
than 2.5mm square multistrand copper wire and therefore provides a better
earth.

Tell me again how Telco gear and TV/Radio Transmitters never ever suffer
Lightning damage.

Tell me how long your 1KJ mov lasts in a Direct Lightning strike ?

how long does a surge last ? - what is the definition of a surge ?

But then again I am probably assuming w_tom understands enough basic physics
to answer these questions.....

what do you do or what did you used to do for a living ?

Essential to earthing a surge is the single point earth
ground. Earthing at multiple points can mean a surge uses
household appliances to destructively obtain that other earth
ground rod. For example, if earth that a surge seeks is to
the east, then a surge that strikes western side utility wires
or even west side earth can travel into the the house via west
side utility wire or via west side earth ground rod, then pass
destructively through household appliances, then enter earth
via the east side ground rod.

He is in Australia dim-wit this means his house wiring is earthed at a
single earth stake that is also bonded to the MEN earth system.

Earthing is a concept called equipotential. One way to
create this equipotential is a single point earth ground. To
make it more effective, the more serious buildings connect
that single point ground also to a big loop that surrounds the
building, or to Ufer ground in the foundation footings, or
wire mesh embedded in the concrete floor - all connected to
that single point ground. The only connection between
interior grounds to that earth ground is a single point.

BTW, computer motherboards should be attached to chassis
using the same principle (only one conductive standoff) for
same electrical reasons.

Nope try again you cannot even get basic, simple fact right - what about the
earth wire to the PSU ????

Yes, the connection from a wire to earth ground must be less
than three meters which is why receptacle grounds are not
earth grounds. Those receptacle grounds are safety grounds -
to connect to breaker box single point safety ground. Breaker
box safety ground does connect to earth ground. But they are
distinctly different grounds, wired together, so that the same
grounding wires accomplish multiple solutions.

Some examples of 'whole house' protectors:
AC electric
http://www.keison.co.uk/furse/furse06.htm
Telephone
http://www.one.co.uk/catalogue/telebyte/LightSurgeProtect/22PX.HTM
http://www.keison.co.uk/furse/furse11.htm
Network
http://www.keison.co.uk/furse/furse08.htm
http://www.keison.co.uk/furse/furse07.htm
http://www.keison.co.uk/furse/furse19.htm

And most 'whole house protectors have the same weakness that is they do not
and cannot protect against near or direct strikes or even the kind of damage
described by the OP - Tim unless you live inside a metal box.

You see w_tom is taking Lightning protection Techniques which do enjoy some
(but not complete) success protecting Transmitters and Telco installations
and since he does not understand all the theory behind it he assumes it will
work in all situations


In Australia all the house wiring comes back to a single earth point that is
bonded to an earth stake and the Neutral wire

Avoid anything recommended by w_tom

Ummmm no, No and No

Nope they dont tend to work very well anyway they dont need to the MEN
system provides pretty good protection to begin with.

Regards
Richard Freeman

 

[Tim Edwards]

Ok thanks Richard. I think I'll just stick with the powerstip ones I have
ATM and maybe look at a UPS in future.