Eigenvector wrote:
"volts500" wrote in message
oups.com...
Eigenvector wrote:
I asked the electrician why there was such a difference between the two
types of wires but never got an answer other than "It's code".

So when I had my earth ground installed in my panel, 2 ground rods ~4
feet
apart with a 10 gauge wire connected between them and the panel.

At the same time he installed bonding for the hot, cold, and gas pipes -
but
for this he used like 5 twisted strand 10 gauge wires - it was a HUGE
copper cable.

When I asked why the bonding got the big cables and the earth ground got
the
single 10 gauge he mentioned that 10 gauge is really all that is required
for good solid ground and that's what code called for. But he didn't
really
explain why the bonding required such massive wires. It's not like I
think
he cheated me on the copper, I trust the company he works for and he did
very good frugal work in the panel. I just kind of want to know - why
the
difference in size? If anything I would expect the situation to be
reversed, the massive cable to the ground rods and the small wire to the
pipes.
NEC and engineering studies have determined that a ground rod cannot
dissipate any more electrons into the earth in a given time than can be
carried by a #6 copper wire, thus there is no need to use a wire larger
than a #6 copper for ground rod, pipe or plate electrodes.

Now I'm curious........what was used to ground your electric system
before all this?


The galvanized pipes. Basically nothing.



The galvanized pipes were undoubtedly connected to an underground metal
water pipe that was metal to metal connected to a metal well casing or a
public water system consisting of literally miles of pipe and you call
that nothing. Underground metal water pipes of significant length or
depth make a much better grounding electrode than those two driven rods
you are asking about. The entire purpose of the two driven metal ground
rods is to provide a backup to the water piping in case it is opened
during plumbing work or replaced with plastic during a future repair.
If your entire home were piped with plastic so that there was no
metallic piping inside the home and the only metal piping was the
underground metal water piping that supplies the building the code would
still require that underground metal water piping of twenty or more feet
in length be used as a grounding electrode.
--
Tom Horne

"This alternating current stuff is just a fad. It is much too dangerous
for general use." Thomas Alva Edison