Re: Backups

On May 29, 4:47 pm, Will Honea <who...@xxxxxxxxx> wrote:
...
Over the years, I have found that the biggest single problem with protection
schemes has been the quality of the grounding system. Being so simple, we
rarely pay attention to it once installed. Any connections in the ground
system need to be inspected at regular for intervals for corrosion and
continuity. Clean or tighten connectors, etc. That applies for both
lightning as well as surge systems. I worked mainly with industrial
locations, but you would be surprised at what a hair drier or electric
drill can do to your power lines!

Spikes from a hair dryer, etc are made irrelevant by protection
already inside electronic power supplies. But as Will's example
demonstrated, surge protector devices are not surge protection. It is
routine for a telephone switching center (Central Office) connected to
overhead wires all over town to suffer hundreds of spikes during a
thunderstorm. And yet how many times has your CO been down for four
days. No telephone service anywhere in town for four days while they
replace a surge damaged computer?

It is routine to have no damage from direct lightning strikes as
even demonstrated by equipment installed on Hoher Peissenberg mountain
in Germany when direct lightning strikes were measured and recorded
for their Nov 1998 IEEE paper. It's not protector devices that define
protection. A lightning path to earth defines protection or damage.
If that path is through electronics, then electronics fail. If the
human installs a superior earthing path before electronics (divert the
surge), then electronics is not harmed.

Bud totally misrepresents what IEEE demands for protection. IEEE
defines protection in standards. Numerous IEEE Standards state
bluntly what is required for protection. From IEEE Red Book (IEEE
Standard 141):
In actual practice, lightning protection is achieve by the
process of interception of lightning produced surges,
diverting them to ground, and by altering their
associated wave shapes.

Other IEEE Standards echo the same statement.

Earthing is why one 'whole house' protector is so effective for
homes. Earthing a protector distant from electronics and adjacent to
that earthing electrode is why your phone company, connected to
overhead wires all over town, suffer repeated direct surges - and no
damage.

But then one need only learn from professionals who suffer direct
lightning strikes without damage:
http://www.harvardrepeater.org/news/lightning.html
Well I assert, from personal and broadcast experience spanning
30 years, that you can design a system that will handle *direct
lightning strikes* on a routine basis. It takes some planning and
careful layout, but it's not hard, nor is it overly expensive. At
WXIA-TV, my other job, we take direct lightning strikes nearly
every time there's a thunderstorm. Our downtime from such
strikes is almost non-existant. The last time we went down from
a strike, it was due to a strike on the power company's lines
knocking *them* out, ...
Since my disasterous strike, I've been campaigning vigorously
to educate amateurs that you *can* avoid damage from direct
strikes. The belief that there's no protection from direct strike
damage is *myth*. ...
The keys to effective lightning protection are surprisingly simple,
and surprisingly less than obvious. Of course you *must* have a
single point ground system that eliminates all ground loops. And
you must present a low *impedance* path for the energy to go
That's most generally a low *inductance* path rather than just a
low ohm DC path.

Demonstrated is why an effective protector requires a 'less than 10
foot' connection to earth using wire with no sharp bends, no splices,
and a single point earth ground. A protector is only as effective as
its earthing. One 'whole house' protector is far more effective than
a house full of plug-in protectors. The protector is only as
effective as its earthing.

.

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