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JF Mezei
*nix forums Guru
Joined: 21 Jul 2005
Posts: 2556
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 Posted: Wed Jul 19, 2006 6:02 pm Post subject:
Re: http://h71000.www7.hp.com/?
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Just though of the perfect protection from lightning:
Load your house with a billion volts. This will repel lightning that is
seeking ground :-)
And this has the nice side advantage of being a truly good theft
deterrant for the whole home  |
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w_tom
*nix forums beginner
Joined: 19 Mar 2005
Posts: 28
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| Posted: Thu Jul 20, 2006 4:05 pm Post subject:
Re: http://h71000.www7.hp.com/?
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Bud-- wrote:
| Quote: | ...
A 'collar' would not likely increase the wire inductance significantly
and the increased inductance wouldn't block a lightning induced surge. A
collar wouldn't provide a path to ground unless there was a conductor to
grounded collar arc.
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One who routinely follows me around to represent plug-in protector
manufacturers even denies what is routinely done in some higher
reliability facilities that do not suffer damage. Routing each wire
through the bulkhead does increase wire impedance and therefore
enhances protection. It is one solution discussed in legendary
application notes from Polyphaser where even coax cable is routed
through the bulkhead to increase protection:
http://www.polyphaser.com/ppc_ptd_home.aspx
The bulkhead solution was also installed to eliminate surge damage
from Orange County emergency response centers in FL:
http://www.psihq.com/AllCopper.htm
A bulkhead (collar) can increase wire impedance. But where that
impedance is increased or minimized is important.
What did professionals do to eliminate damage? Did they install
plug-in protectors as Bud claims? Of course not. They corrected
earthing AND they installed other solutions so that lightning would
find earth on non-destructive paths; not inside the building. Of
course, plug-in protectors don't do this well proven technique. So
plug-in protector manufacturers do not even claim to provide effective
protection in their own numerical specifications. Instead, Bud
promotes those ineffective and so much more expensive solutions.
The bulkhead is effective because so much transient energy is outside
the wire. But this bulkhead (collar), alone, is not sufficient
protection. It is an enhancement after THE most essential protection
device is installed. Lightning will find paths to earth via electronics
if not provided a many times shorter earthing path. After THE most
critical component in a protection 'system' is installed, only then
should other enhancements such as the bulkhead be considered.
Making a path to earth as low impedance as possible is why the
earthing wire must be 'less than 10 feet'. Other considerations that
enhance earthing beyond post 1990 National Electrical Code (NEC)
requirements include no sharp bends, no splices, all wires routed
separated from non-earthing wires (so as to not create induced
transients), AND routed not through metallic conduits. Remember, that
collar, conduit, or bulkhead causes a wire impedance increase. Whereas
increased wire impedance is desirable after the earth ground, that same
wire impedance is very undesirable in connection TO earth ground.
Making earthing connection low impedance is also what that Orange
County solution accomplished. Earthing is the most essential part of a
protection 'system'. Plug-in protectors represented by Bud just
totally forget the whole concept. They don't provide the dedicated
earthing wire so necessary to make those MOVs effective. So Bud
completely ignores such earthing to promote the more profitable and
ineffective solution.
Meanwhile, where is transient's energy absorbed? In MOV as Bud would
have you believe? Of course not. Numbers of joules in plug-in
protectors are woefully too small to absorb that energy. Surge energy
is dissipated in earth. Again, earthing is the most essential
component in a protection system which is why responsible protectors
manufacturers provide a dedicated earthing wire. We earth direct
strikes so that protection already inside appliances is not
overwhelmed. Ineffective protectors have no such earthing, and avoid
earthing discussions. No earth ground means no effective protection.
So those who represent plug-in protector manufacturers hope to ignore
the entire concept - as if those MOVs will somehow absorb what three
miles of sky could not stop.
Earthing is the most critical component in any protection system as
professionals will routinely note - as Ben Franklin demonstrated in
1752. As demonstrated in this figure from but another responsible
industry professional:
http://www.erico.com/public/library/fep/technotes/tncr002.pdf |
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