"Thomas Horne" wrote in message
link.net...
Jimmie D wrote:
"Bud--" wrote in message
.. .
Jimmie D wrote:

Hopefully you are not really using the water pipe for a ground for
your electrical service. Hopefully your plumbing is just bonded to
the electrical ground. Dont even think about using this for lightning
protection. Nothing like having lightning run in on your plumbing
while taking a bath or have it run in on yor ground and eat about $7K
worth of test equipment(my bad).

Jimmie
Jimmie

DE KB3OPR

I am an electrician by craft. The US National Electric Code Requires
that underground metal water piping on the premise be used as a
grounding electrode for the electrical system. There is no way around
it. No matter how fast people talk you cannot avoid using an
underground metal piping system as a grounding electrode unless the
electrical inspector is incompetent.
--
Tom Horne

Tom you are confusing grounding with bonding, the plumbing should be
bonded to ground but not used for ground, at least this is getting to
be the rule in most places. I know that using the plumbing for ground
is still acceptaable in places and in a lot of places it is still
acceptable if if the local code permitted it at the time it was
installed(grandfathering)..

An electrician confusing grounding and bonding - that is pretty funny.

From the US National Electrical Code
?250.50 Grounding Electrode System
All grounding electrodes as described in 250.52(A)(1) through (A)(6)
that are present at each building or structure served shall be bonded
together to form the grounding electrode system.?

?250.52(A)(1) Metal Underground Water Pipe?
(10 feet or more metal in earth)

Using underground metal water pipe as a grounding electrode is REQUIRED.
And this has been a requirement for a very long time. Local codes may be
different from the NEC, but it is unlikely they are different on this.

And if you just "bond" metal water pipe it will work as a grounding
electrode anyway.

--
bud--


True enough but there is a difference, grounding is connecting to earth
bonding is tying conductive structures together so they are at equal
potential. Ground is a single point that everything else is bonded.
Ground should be a stucture that the qualified electrician should be
familar with not plumbing that may or may not be intact. If you dont
believe me just try to get an electrical inspection on a new home without
a ground rod installed.

BTW the NEC is a minimum standard not a guide on how to wire your
house.or perform grounding and bonding.

You wouldnt believe what electricians dont know, like checking phase
rotation before turning on a new 200KW UPS. or megging out lines before
turning on new parking lot lights or making sure a generator is not
backfeeding a line before working on it. All things I have seen
electricans screw up in the past year.

Jimmie

Jimmie
I can assure you I don't do that sort of careless nonsense. I can also
assure you that whenever I'm involved before the foundation is poured or
at least prior to it being back filled there will be no driven rods on
that job. They are the single least effective electrode you can install.
When I have to install driven rods, such as for a heavy up, I will stack
them using rod couplers until I'm under twenty five ohms and perform a
witnessed test for the inspector. I consider eight foot driven rods a
complete waste of time. Mind you I'll install them when I'm forced to but
you will usually find mine driven through the bottom of a three foot deep
trench on at least twenty feet of bare copper number two AWG grounding
electrode conductor.

As for the US NEC being a minimum standard that is not always true. In at
least ten states it is both the minimum and the maximum standard that a
public electrical inspector may apply. So called "min max" states do not
allow the local governments to amend the US NEC. Were the US NEC is the
minimum standard you have to use underground metal water piping as a
grounding electrode whether or not it jibes with your religious beliefs
about what constitutes an electrode or not. If you were bonding the
plumbing you could do that with a conductor sized for the largest branch
circuit supplying an appliance that is attached to the plumbing. When you
are using the piping as an electrode you must size the conductor to the
size of the service entry conductors. People like W Tom cannot bring
themselves to admit that underground metal water piping is an effective
grounding electrode and worse still that it more effective then most of
the other electrodes listed in the US NEC at least in homes. I always
check the impedance of my grounding electrodes and that's what the
measurements say to me.
--
Tom Horne

The point I am trying to make is that the ground system must be sufficent on
its own and not need to connect to the buildings plumbing to improve the
ground. You should never depend on the plumbing especially on residential
work because you can not maintain control of modifications to that plumbing
system. Good example is my in-laws home, for years the house connected to
the well via 1 inch metal pipe and this was also the ground for the house as
it was built in 1974. When the new well was drilled plastic pipe was
installed to the new well with no groundwire going back to the well casing.
A couple of years later a new HVAC system was installed and when there was
an accidental short circuit the well pump was fried. This would not have
happened if a proper grounding system had been installed at the house
instead of relying on the plumbing. Professionals have a responsibility to
idiot -proof there work as much as possible but you know how it is, sooner
or later someone makes a better idiot.

The fact that the water pipes may be effective or even better than the
installed ground really have nothing to do with anything. Ground sytems are
for grounding, Plumbing is for water. Electrians dont do plumbing and
plumbers dont rewire homes.

Jimmie