On Oct 16, 2:57 am, "John Gilmer" wrote:
We had two severe thunderstorms about 2 weeks apart. We lost a total of 3
motherboards. In the second incident, a new motherboard was taken out.
That's convinced me to: 1) just buy a new computer than screw about with MB
replacement; and 2) get UPS for each computer. The main risk to our
machines is now just the network cable. If we go wireless, we should be
safe from just about anything.

Now review that NIST discussion. What does a protector do? Page 8
of 24:
http://www.nist.gov/public_affairs/p.../surgesfnl.pdf
You cannot really suppress a surge altogether, nor
"arrest" it. What these protective devices do is
neither suppress nor arrest a surge, but simply
divert it to ground, where it can do no harm. So
a name that makes sense would be "surge diverter"
but it was not picked.

Where does that UPS 'divert' a surge to. Effective protectors are
located where wires enter the building. Your computer already has
significant internal protection. Anything a plug-in protector might do
is already inside that computer. Internal protection was overwhelmed
because you let a surge enter the building. Now that UPS will somehow
stop or absorb what three miles of sky could not? Of course not.
That also is not what the NIST says effective protectors do.

Your phone line must already have a 'whole house' protector
installed free by the telco. Your cable needs no protector because it
can be earthed without any protector. Inspect both. Do they make the
also required 'less than 10 foot' connection to a common earthing
electrode?

Your cable company will even recommend removing plug-in protectors
or a UPS on their cable. Cable for protection is earthed where it
enters the building. That protector will only degrade cable signals -
provide no effective protection. In each case, what defines
protection? The NIST document says an effective protector *diverts*
to earth ground.

Well that UPS has maybe a paltry 300 joules. That is near zero.
But near zero protection is enough to claim "IT CONTAINS PROTECTION
FROM DIRECT LIGHTNING STRIKES". Myths like this are widespread and
encouraged routinely by Bud.

Meanwhile, what is the most common source of surge damage? Incoming
on AC mains. Wires that are most exposed at the street. Just like
lightning striking antennas atop the Empire State Building, your AC
wires carry a direct lightning strike into the motherboard. This
because the surge was not earth where it entered the building - at the
circuit breaker box.

That box already should contain a 'less than 10 foot' earthing
connection. If not, then a new earthing electrode must be installed
to meet post 1990 National Electrical Code requirements. No earth
ground means ... well what does the NIST say? It *diverts* a surge to
earth ground. And you have no (insufficient) earthing? What defines
an effective protector? Its earthing. Where is the surge energy
dissipated? In earth. Will a protector or UPS absorb that energy
that 3 miles of sky could not stop? Of course not. Only place that
surge energy gets harmlessly dissipated is in earth.

Install only one 'whole house' protector on AC mains with that
short connection to earth. Massively less money and protection that
actually can earth surges. Things even more important than a
computer (furnace controls, bathroom and kitchen GFCIs, smoke
detectors) are also protected. Protected by a device that far exceeds
what the UPS even claims to accomplish. Did you notice the UPS does
not even make surge protector claims in numeric specifications? If it
provides numbers, you might see 'near zero' protection.

A protector that has no earthing is massively profitable AND does
not even claim to protect from the type of surge that typically
damages computer motherboards. Don't take my word for it. Where is
each type of surge defined AND numbers for that protection? A UPS
makes no such claims. Somehow a relay that takes tens of
milliseconds to open will stop a surge that does damage in
microseconds? That is how UPS protection works?

Install one 'whole house' protector. Verify earthing for telephone
and cable TV protection exists and is properly installed. If
necessary, get building earthing upgraded to meet and exceed post 1990
code requirements. What does the NIST says protector does? It
*diverts* a surge to earth ground. How does it do that if you
earthing is missing or insufficient?

Why do cable companies recommend removing a protector from their
cable? Protector has no earthing - does ineffective protection - and
degrades TV signal. Every protector as noted in that NIST citation is
only as good as its earth ground. No earth ground means no place for
surge energy to be diverted - no effective protection.

One 'whole house' protector does far more than any protector
adjacent to electronics - at tens of times less money. Get your
earthing inspected or upgraded. Get one 'whole house' protector for
everything. Verify your cable and telephone protector are properly
installed. Or waste money on devices that will not even claim to
provide that protection - in numeric specs?

Any wire that is not earthed (by direct connection or protector)
where it enters the building means no effective protection. There is
no 'magic box' protector. Protection even in the early 20th Century
has always been defined by earthing. The effective protector makes a
'less than 10 foot' connection to earth ground ... to *divert* the
surge.