wrote:
Chip C wrote:

I'm confident that my responses will draw at least as many flames
as
your questions would.

Thank you for your detailed reply Chip. It is very helpful.

I am still a bit fuzzy about the ground bar and neutral bar being
'connected' at the service panel. Won't all electricity just goes to
the ground in that case? I know it sounds silly, but what's the
difference between connecting the ground/neutral at the panel vs
connecting them at the receptacle? a wire is a wire right?

A lot of the rules are for what happens if something goes wrong. If you
analyze the rules based on normal operation you get a lot of "what's
that for? that doesn't do anything! that's redundant! that carries no
current!" But many years of analyzing electrocutions, fires and plain
old power failures have given us code rules that cover a vast array of
what-ifs.

HorneTD's response included some excellent fundamental points:
electricity takes ALL routes back to its source, and the US and Canada
use a multi-point grounded neutral system in which the neutral is
grounded at the power company's transformer AND your house. This means
that the ground AND the power company's neutral are both ways to
complete the big circuit back to the generator. I believe that this
fact has implications that I don't really understand, again in the
realm of things that can go wrong in odd circumstances.

I suspected the answer to "why only one ground/grouding rod" is
the big IF part in my post. Thank you for clearifying that part

let me ask another (not a troll!) question, in many areas, redundancy
is good. if one fails, the other still works. isn't having two
properly done ground rods better than one? If one fails, then the
other should still work? having the code calling for one and only
grounding to be done at the service panel, then the whole system will
be depending on that grounding work correctly. The probability of one
fails is much higher than the probability of both fails right?

Redundancy can bite you back. In the case of grounding there is a
phenomenon called "ground loop" caused by natural and other phenomena
(soil chemistry, induced voltages from radio waves, earth's magnetic
field) which can mean that one point in your yard is at a different
electrical potential than another. That means that your two ground rods
are at different voltages and a current will flow from one to the other
via your ground wires. This can induce a voltage on your ground wires,
exactly the opposite of what you want. Effects could range from
nothing, to minor static shocks when you touch plumbing, to
interference with radio and tv reception and other electronic devices,
to constant low-grade currents that promote corrosion in plumbing or
structural steel pieces.

I mean redundancy is why I backup my data to CDRs.

"Verily, he who would be wise sayeth: Put not all thine eggs in one
basket; but I say to you, he who divides his eggs among baskets has
scattered his fortune to the winds, and knoweth not what he hath and
hath not; and I say to you, he who is truly wise shall put all his eggs
in one basket -- AND WATCH THAT BASKET!"

So if I understand it correctly, the grounding for the satellite dish
for example, is to connect the metal part of the dish to the ground
bar in the main service panel via a proper ground wire? not to the
earth right under the satellite dish (or roof) which I can dug a hole
and bury the bare copper wire that came with my satellite install
kit?
And the reason being the ground at the servie panel will most likely
provide less resistence than my bare wire?

I'm going to defer to HorneTD's post for this one.

Any discussion of grounding really ought to mention lightening, too;
but that's a big complication. It helps to remember that lightening
protection, like grounding for masts and lightening rods on the roof,
is never aimed at conducting lightening "safely" to the ground, since
that would require conductors the size of your arm. It's all aimed at
draining off static charge that would otherwise accumulate and attract
lighting by providing a path of ionized air.

Chip C