w_tom,
I read your referenced thread with great interest. The principles were
clearly explained but some of the stuff about different types of
surges was over my head (I'm a physician whose use and knowledge of
electricity is pretty much limited to dc defibrillators).
At my newly constructed home, I employed an electrician whose business
is limited to surge protection to provide and install the whole-house
suppressor. He put in an Eaton/Cutler Hammer CHSP Ultra that comes
with a $100,000 warranty. He says he's never in his career seen a
claim against Cutler Hammer for damage occurring in spite of this
unit. I have faith in this electrician and his recommendations, but
the whole-house suppressor was MUCH smaller than what I expected from
my minuscule knowledge of electricity.
Here's my question: This unit is mounted on the side of the
circuit-breaker box, so where is it's connection to ground? It is
very clearly within ten feet of the external earthing rod, but does it
connect to this through the inside of the breaker box? Can you give
me a brief explanation, of how this thing is wired to protect all the
circuits in the house? Also, in one of your posts, you mentioned that
phones and cable do not require separate protection because they have
built-in surge suppression, and, yet, my guy installed a companion
module (on the whole-house suppressor) for cable (not phone)
connections. Is that superfluous?

Thanks for all the time you take to provide us with these
explanations. They're great.

On Fri, 14 Jan 2005 02:38:02 -0500, w_tom wrote:

We still don't build as if the transistor exists.
Principles are well proven in telephone switching facilities.
A massive improvement can be install in homes for about $1 per
protected appliance. Effective protection is just not that
expensive. But unfortunately, some spend many times more
money for far less effective (plug-in) solutions. They
purchase protectors that can even contribute to damage of an
adjacent computer. Then rumors such as 'too slow' persist.

Concepts requires comprehension of some basic principles.
Fundamental to surge protection is why a Ben Franklin
lightning rod works. Too many assume based upon what they see
- that a lightning rod is protection. Wrong. The protection
is and is defined by the quality of earth ground. That is the
art - earthing. An art only because it is not intuitively
obvious. Protectors are only as effective as the protection
connected to. Protector and protection are two different
components of a surge protection 'system'.

Protection is earth ground. Sometimes earthing installed
standard in most buildings (sufficient for human safety) is
not sufficient for transistor safety. Human safety is mostly
concerned with wire 'resistance'. Transistor safety is mostly
concerned with wire impedance. Sometimes the earthing systems
must be enhanced to also provide transistor protection.

Even ineffective protectors operate plenty fast - as did the
slower GDTs decades previous that operated so effectively.
Problems understanding effective protection even causes one to
confuse a wall receptacle safety ground (also called equipment
ground) with something located elsewhere and completely
different - earth ground. Why are they different? Wire has
impedance.

These concepts are introduced in a previous discussion
entitled "Is it safe to use computer during lightning/thunder
storm?" in the newsgroup sci.electronics.basics on 22 Sept
2004 at
http://tinyurl.com/5fu8n
Further details from same author (including figures from
industry professionals) are in two posts that precede this
above post.

Protection is so easily installed and is so effective that
damage is considered a human failure. One additional point.
Destructive surges occur typically once every eight years.
Five years with no damage proves little. Protection is only
as effective as its earth ground which is why earthing is so
important in telco buildings that must operate without
interruption during every thunderstorm.

notritenoteri wrote:
THe reason they don't operate fast enough is not really the problem
it is the fact that most of them don't. I think your comment about
building grounding is misleading. At least in this country buildings
are well enough grounded to be safe in most circumstances. In
building design it is possible to reach a very high level of
lightening and surge protection. the issue is one of cost mostly. PC
are cheap relatively. My experience (5 years as telecom guy in a
building with about 1000 networked pcs) suggest lightening or surges
are very minor problems. From what I know of lightening protection
engineering it is an art form to some degree. Sometimes the
engineers get it right, sometimes despite the best of designs the
stuff blows.
As I said its the data thats important.
BTW as I said $250 Can will buy you an 800 watt output battery
inverter pack to run your Ipod or laptop on your "camping trip".
That gets you one that plugs into the wall (110-120 here) and
outputs to 2 sockets for a total of 800 watts AC on the other side.
That's it said my piece

Ron