Red wrote:
On Jan 13, 11:56 am, w_tom wrote:

On Jan 12, 12:36 pm, Red wrote:


I didn't say a strike, I said a surge.
I've lost 3 tv's at a different location fromlightningsurges
(nearby but not direct strike) coming into the tuner section via
CATV.

First a lightning strike is a surge.

Second, sacrificial protection does not exist - is a myth. A surge
is electricity. That means electricity flows through everything in
that path from cloud to earth. Only after does something or multiple
things fail. You have assumed surges do damage like waves crashing on
a beach. Electricity does not work that way.

Third, protection is defined in another post on 11 January 2008 in
the newsgroup newsguy.general entitled "Lightning Strikes" at:
http://tinyurl.com/22race
Everything in that post defines what provides TV protection.

Fourth, you have assumed lightning surge entered on cable. Then what
is the outgoing path to earth? Any properly installed cable first
connects to earth ground before rising up to enter the building.
Connected to earth means a surge will not seek earth ground,
destructively, via the TV. What is the incoming surge path? What
good is a 'sacrificial' amp when cable should already dump the
incoming surge to earth before entering the building?

Fifth, surges typically enter from wires located highest on poles -
AC electric. Incoming on AC electric, into TV, and out to earth
ground via tuner and cable. Protection means the incoming wire should
be earthed before entering the building. That is what one properly
earthed 'whole house' protector does. Earthed to the same electrode
that cable TV wire connects.


I'm not going to get into this argument again - it was fought long &
hard many times before. All I'm saying is that theory is one thing
and experience is another. As to cable input, the shield is grounded
but the center conductor is not. Any induced voltage on the center
conductor goes into the tv's tuner section before it finds a path to
ground. And I've had 3 tv's to prove it despite what theory says.
Also, it does not take a strike to create a surge. Many, many times
I've had static electricity jumping 1" to 2" arcs between appliances
in my kitchen when there was a storm in the area but no strikes. I've
had items vibrate on my glass coffee table many seconds before a
strike a half mile away. And yes, my house is properly grounded.
And yes, I have had a lot of experience installing commercial
lightning protection sysyems. Enough experience to say that lightning
will do what it damn well pleases despite what precautions we take.
So the more we do, even it is not within norm, increases our chances
of minimal damage. And that is what I said I did.

Red
Hi,
Yes, speaking of experience, when I was an EIC at LARGE data center in
the basement of a building, we suffered a direct hit. No visible damage
to any equipment per se, but alas, our data stored in the mass storage
devices were all garbled(trashed) needing 3 days non-stop restore
operation from a back up we kept off site. I think when hit direct,
there is no real 100% protection.