Choreboy still does not appreciate that my knowledge comes
from well beyond suffering damage. Suffering damage teaches
little. Notice how theory completely changes Choreboy's
conclusions - the computer protected itself.
I built protectors. Saw some fail spectacularly. Other
worked phenomenally when other unprotected appliances suffered
damage. Even replaces electronic components on damages
equipment to learn why damage happens - ie followed the
circuit path of surges. Experience is useless without the
associate theory.
From junior high school science, one must have both theory
and experience to have knowledge. One without the other is
nothing more than speculation. The theory and my decades of
experience is tempered by something that few can or are
willing to provide - the numbers.
Let's return to Rudy's post. The protector was so grossly
undersized as to abandon an adjacent computer to the
transient. Fortunately the computer had better internal
protection than the grossly undersized power strip. However
Rudy fell into thinking exactly what grossly undersized
protector manufacturers hope he will assume. He assumes a
damaged protector was providing protection. In reality, the
protector that remains functional after the surge is effective
protection. Effective protection means one never even knew
the transient existed.
Now to provide some additional facts. For example, was the
APC sitting between computer and the transient? Mechanically
yes. Electrically no. That surge hit both APC and computer
equally. The APC connects to AC electric as if it was a light
bulb - just like the computer. Choreboy - that is how the
protectors are constructed. They are called shunt mode
protectors because that is how they are wired.
Computers have internal protection. A transient too small
to overwhelm computer protection instead easily destroyed a
grossly undersized protector. Yes, undersized protector. How
many joules in that protector? Why is that plug-in protector
so grossly undersized? Rudy demonstrates why. He then
assumes an ineffective and burned protector did something.
Reality - that computer protected itself. A tiny transient
destroyed the grossly undersized plug-in protector.
Little difference whether the computer is on or off. First,
a powered off computer is always on; just like the TV.
Second, a power strip protector can even provide the transient
with a destructive path through adjacent computer. An
adjacent protector may even contribute to damage of a powered
off computer. No wonder those plug-in manufacturers avoid all
discussion about earthing.
More facts from one who even designed and tested this
stuff. But don't take my word for it. How many joules on
that plug-in protector? If that protector is effective, then
put up the numbers? I keep asking for numbers. Where are
those numbers - the joules?
Does zone of service suggest where a protector will be
effective? No. Those zones only define the electrical
characteristics of a transient. Those zones define where a
protector can be used safely - for human safety. Protectors
that are effective at the appliance are already inside the
appliance. Internal protection that can be overwhelmed if
protection is not installed in those other zones - ie properly
earthed at the service entrance. This is called secondary
protection.
BTW, the utility already has installed protection on the
utility wires. You should inspect this protection - the
primary protection:
http://www.tvtower.com/fpl.html
How does a 'point of use' protector provide protection?
When it makes a 'less than 10 foot' connection to earth
ground. If earthing is not provided, then the protector must
be moved to where earth ground exists: the service entrance.
Also called 'whole house' protector.
The recommended GE THQLSURGE protector was once sold in
Lowes. It was undersized. Yes it could make the 'less than
10 foot' connection to earth. But it was undersized.
Multiple GE THQLSURGE products would increase the joules. But
GE now sells a properly sized 'whole house' protector in
Lowes. Other minimally acceptable 'whole house' protectors
are sold in Lowes (Cutler Hammer) and Home Depot
(Intermatic). Other manufactures of effective protector are
Square D, Leviton, Siemens, and Furse. I don't know of any
APC product that qualifies for that list.
But again, the protector is not protection. Choreboy still
does not yet grasp the point. It is not about "plug-in
protectors are worthless". That was not the point.
Protection is about earthing. More importantly "the quality
of and connection to a single point earth ground".
Choreboy suffered damage even with a 'whole house'
protector. That means he should begin by asking questions
about his earthing system. To talk about protectors as
protection means one does not grasp the concept. To believe a
vaporized protector was effective is only wild speculation.
Single point earth ground. The one absolutely necessary
component. The component that defines protection. Any post
about what protector 'is and is not' effective means the
poster still does not understand the concept. Choreboy's
first question should have been, "Why did my earthing system
fail?"
Again, the three zones do not define what protectors will be
effective. Those zones only define electrically what
transients can be expected. Zones define what is required so
that a protector will not harm humans. To provide protection
in those zones requires something not defined by those zones -
earthing. Something that some in this discussion have not yet
asked about. Why? Still some here confuse a protector with
protection. Without questions about a unique type of
grounding: earthing, then concepts of transient protection are
not yet understood. Protection is only as effective as the
earth ground.
AlanBown wrote:
SOARS book on grounding has some easy text. Try your library.
IEEE 519 (I think) says for surge protection you need to do 2 of
the 3 zones. One zone is the utility so that is out. Next is the
service, next is point of use. So as a user you can protect the
service and point of use.
I just installed a GE made surge arrestor for my GE service. Just
plugs in to the buss and acts like a 2 pole breaker with a green
light.
http://www.geindustrial.com/cwc/prod...g&lan g=en_US
incase your interested, other manufactures make them for their
panels as well.
I also have point of use protection. Most of the ones made today have
protection levels of around 330v. Remember Metal Oxide Varsities are
UL tested ONCE. Not twice. I replace all of my point of use stuff
every 2 years just before the Monsoons.
If your really into it test your grounding at your service. You will
need to beg or borrow special equipment for this. Check out
http://www.groundtesterstore.com/clamp/aemc3731.php
I have used one of these many times. Especially when driving grounds
for fall of potential is out of the question. Other companies make
them as well.