Jimmie D wrote:

Thomas Horne wrote:
Jimmie D wrote:
Thomas Horne wrote:
Jimmie D wrote:
Bud wrote:
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


And my point is that your opinion does not jibe with the National
Electric
Code.
--
Tom Horne

Please Tom, tell me in what way that the grounding system should be
sufficent on its own and not having to rely on the plumbing to provide
grounding for an electrical system in violation of the NEC. Also please
tell
me how you intend to prevent the scenario I discribed where the ground
system was completely disconnected from the home when the well's metal
plumbing was replaced with plastic.

The Code is the min and max that an inspector can apply to an inspection
This means that the inspector cant find fault with using plumbing for
grounding if this is what the code says, it doesnt mean that the inspector
can find fault if it is built better than code requirements, so again I
say the code is written to a minimum spec. Your own definition of min max
confirms this. Traditionally the NEC has the lowest minimum standard and
the
state and local codes usually have a higher standard., there may be some
exceptions to this. I will will stipulate that using plumbing for ground
may
be "to code" in some places but it still is not a good way to ground your
house and definately should not be used for a lightning ground.

Jimmie

I've seen this thread go back & forth. Back when my voice hadn't yet
changed, my folks bought a small piece of land for weekend travel-trailer
camping. At the time, there was power available but no water. We wanted AC
power for the otherwise self-contained trailer, and followed the
requirements set down by the county PUD. We installed a utility pole, with
service entrance, weatherproof breaker panel, and weatherproof outlet. All
we had available for grounding was an 8' rod driven into the ground next to
the pole. There was NO water pipe with which to connect the ground wire.

Fast forward to recent years (my voice has long-since changed, but now what
graying hair I have left is falling out). When I decided to re-pour the
concrete slab for my kitchen porch next to my service entrance, I found what
was left of a 4' x 3/8" ground rod embedded in the old concrete (the entire
#14 wire connected to it had also been embedded in the concrete.) There's
no evidence of a connection to the water system. I replaced the rod with an
8" x 1/2" unit from the home improvement box store, and connected it to the
service entrance with a #4 wire.

Thankfully, when the utility pole that serves my house continued to lean
away from my house (and the neutral opened), the ground rod kept L1 & L2
from swinging too wildly. There's a transformer on the pole that serves my
house, with a ground rod next to the pole. I guesstimated the ground
resistance at about 1 or 2 ohms. Of course, when they repaired their drop
wire, the PUD had to inspect my service entrance to make sure it met the
minimum requirement. The entire pole & guying has since been changed.
Still, I keep an eye on the slack in the drop wire to my house!

An interesting observation about ground rods... a 4'x3/8" rod = 56.55 sq. in
surface area, while a 8'x1/2" rod = 150.80 sq. in surface area. Of course,
more metal in the ground could only be better. Does anyone have a nice BIG
copper kettle for sale? ;^)

Bryan WA7PRC