"CW" wrote in message .net...
All ground rods have to be connected together to comply with the NEC.

Not only that, but at least the version that's applicable to my locality
says that:

1. The point at which they are connected together must be the AC entrance
panel. They absolutely must never be connected together over the inside-
to-the-house ground wiring (and I think I understand why... you do not
want your house wiring to be carrying a couple thousand amps in case of
a nearby lightning strike).

2. The cold water pipe must also be connected to the AC entrance panel.
I'm a little less clear on why that must be, but it doesn't seem to hurt
anything.

There's a whole litany of what type of ground rod must be used and
what gauge of wire too... I've got more reading to do. I think (but I'm
not sure) that the copper pipes I sank for my experiment are not good enough
for a code-compliant ground because they are both too short (5 feet is
too short) and not copper plated steel. The experiment was still worthwhile
in that it showed how bad the 30-year-old house ground was.

There are some additional rules if a tower is involved but I don't have
a tower so I didn't pay any attention to them.

Tim.