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Bud--

wrote:
In alt.tv.tech.hdtv bud-- wrote:

| According to NIST guide, US insurance information indicates equipment
| most frequently damaged by lightning is
| computers with a modem connection
| TVs, VCRs and similar equipment (presumably with cable TV
| connections).
| All can be damaged by high voltages between power and signal wires.

And this is new information how?

Irrelevant comment.

| This suppressor includes, in the unit, ports for cable and phone. That
| limits the voltages at the entrance point. You can still get problems
| downstream. One possibility is a very near strike producing direct
| induction with wiring acting as a long wire or loop antenna.

Of course. And this is new info?

Irrelevant comment.

| A rather common recommendation is to use a power service suppressor to
| provide gross limitation and a plug-in suppressor at "sensitive
| electronics" particularly with signal and power connections.

I would add to that, to protect ALL metallic wiring coming in to the
building at one place. That way you keep all at the same potential
and using a single point of earthing.

If you read what I wrote, you would have seen that is what I already
said below:
"A service panel suppressor does not limit the voltage between power and
signal wires. To do that you need a short ground wire from the signal
entrance protector to the ground at the power service (or the combined
suppressor above)."

But of course why would you read what someone else wrote.

| | For the next best suppressor - QO2175SB and HOM2175SB
| | - The connected equipment warranty $ does not include "electronic
| | devices such as: microwave ovens, audio and stereo components, video
| | equipment, televisions, and computers."
| |
| | It appears none of w_'s companies has a high reputation.
|
| Or maybe it's a different type of suppressor. Did you even look?
|
| The differences have absolutely no relevance for the response to w_.
|
| But this one is a plug-onto-the-bus unit with suppression only for power
| wires.
|
| A service panel suppressor does not limit the voltage between power and
| signal wires. To do that you need a short ground wire from the signal
| entrance protector to the ground at the power service (or the combined
| suppressor above). SquareD has no idea what is in your house.

Or a combined entrance suppressor. I don't know if anyone makes one.

If you would have read what I wrote, you would have seen that is what
the 1st SquareD suppressor is. In fact right above your reply is "(or
the combined suppressor above)".

If you read what w_ wrote, trader wouldn’t have to explain what w_ said.

| There are other possible sources of damage a power-service-only
| suppressor does nothing about, including high voltage between conductor
| and shield in cable wire, which is not limited by the cable entrance
| ground block.

It can be limited to some degree by the grounding block by having an arc
crossover inside. If the voltage exceeds the arc breakdown, you then have
a much lower impedance for center conductor surges to get to ground.

What is the breakdown voltage? What is the immunity level of a TV tuner?
Gas discharge tubes, among other devices, are used because they clamp at
a low voltage.

| Maybe you should look at the Eaton-Cutler-Hammer devices.
|
| Maybe you should look at CH. I don't really care.

If you want to see options beyond what SQD has, then do look at CH.
I have downloaded the SQD and CH catalogs, so I can look (but I will
for myself, not for you).

If you would read what has been written you would not make dumb
comments. My original response was to w_. My point was one of w_'s
"responsible manufacturers" (CH) makes plug–in suppressors. "I don’t
really care" what else CH has. You brought it up. I am not, and was not,
interested.

| The only sources you are looking at simply give a generic list of what kinds
| of things you might use. There are no scientific explanations to help you
| figure out what is needed in your particular situation for you to achieve the
| level of protection you want. OTOH, I have my doubts about your ability to
| understand the science, so that may explain why they limited things to a few
| simplistic illustrations in what is really just a "to do" guide that does not
| cover all situations or all levels of protection.
|
| I have read a lot of sources, including many technical papers on surges
| and surge suppression. You should have figured that out from references
| provided previously, which included several technical papers. But you
| seem to do minimal reading of reading of what others write.

Given your long diatribes, and your fixation on how you respond to others
in an accusatory manner, a lot of your posts go unread even by me.

Apparently not enough of my posts go unread by you.

I have tried to respond to your posts in other threads on a technical level.
In fact your post in this thread started out hostile.

| You suggest experts in the field "missed a lot of reality" and "flubbed
| the experiment".

I propose that as one explanation as to why these guides come up short on
the explanations.

Translation - they don't say what you believe. They "missed a lot of
reality" was in response to one of your beliefs that is not found in any
of the rather extensive reading I have done. And another of your beliefs
for which you have no supporting cite.

| You discount the IEEE guide. It comes from the IEEE Surge Protection
| Devices Committee, was peer reviewed in the IEEE, and is aimed at
| technical people including electrical engineers. If you ever read it you
| would find "scientific explanations". You might also find "scientific
| explanations" in the technical papers I have referenced, which you
| probably have not read.

The guide I read that you pointed me to simply did not cover the whole topic.
It left out lots of things. Maybe what it covered was all technically correct.
But it was not a useful guide for the purpose of determing what solution is
needed for all situations.

Wow - what a shortcoming. It isn't a 1000 page book.

And look carefully at the name "IEEE Surge Protection Devices Committee".
This is about DEVICES. Proper surge protection involves MORE than just
devices. If you are in the business of designing a DEVICE, then sure, go
with their advice. If you need to select a DEVICE to fit into an overall
plan of surge protection, then sure, use their information about devices.
But when the issue has a broader scope than just devices, you may need to
recognize that you won't get all your information from one place.

If you had read what I have written it is obvious I have gotten
information from many places.

And you are again discounting a guide written by experts, peer reviewed
by experts, published by the IEEE, and aimed at technical people. You
apparently think electrical engineers are idiots. Where you disagree
with the guide you have not cited a source that supports your belief.

That assumes you actually read the guide. Unlikely, since you said it
has no "scientific explanations". But what could you learn from mere
experts.

| But what could -you- learn by reading what others write. There
| apparently is no expert but you.

I'm not claiming to be an expert. But when people talk about things with
even less knowledge than I have, and especially when what they say contradicts
actual observations, then I know _they_ cannot be an expert (or else there is
some misinformation and the situations are not really a match).

Translation - Phil is smarter than the experts.

For example, consider the high frequency issue. High frequency energy is
less common than low frequency energy. Partly this is because the chance
of a closer lightning strike is less than a more distant one. A strike
within 100 meters is only 1/8 as like as a strike outside of 100 meters
but within 300 meters. Some people then feel that they can dismiss high
frequency energy issues entirely.

Francois Martzloff was the surge guru at the NIST and has many published
papers on surges and suppression. In one of them he wrote:
"From this first test, we can draw the conclusion (predictable, but too
often not recognized in qualitative discussions of reflections in wiring
systems) that it is not appropriate to apply classical transmission line
concepts to wiring systems if the front of the wave is not shorter than
the travel time of the impulse. For a 1.2/50 us impulse, this means that
the line must be at least 200 m long before one can think in terms of
classical transmission line behavior."
Residential branch circuits aren't 200m.

Your response: "Then he flubbed the experiment." In another case you
have said Martzloff had a hidden agenda.

You claim lightning induced surges have rise times about a thousand
times faster than accepted IEEE standards - which are experimentally
derived.

One of w_'s favorite professional engineer sources says an 8 microsecond
rise time for a lightning induced surge is a "representative pulse",
with most of the spectrum under 100kHz. You don’t get transmission line
effects at 100kHz.

You still have never provided a cite that supports your opinion.

Summarizing:
Phil doesn't read much of what you write (or cited sources).
Phil is smarter than electrical engineers who are experts in the field.

--
bud--