Roger wrote:
On Mon, 02 Apr 2007 04:08:47 GMT, Thomas Horne
wrote:

Jimmie D wrote:
"Dave" wrote in message
. ..
wrote in message
oups.com...
I would like to propose a grounding arrangement for my [hypothetical]
antenna and get some feedback on it. I have access to the solid-copper
cold-water pipe that enters my home through the basement wall close to
the basement floor.
bad start

This pipe is used [in addition to cold water] for
the service entrance [circuit breaker box] ground.
thats bad news

I was thinking of putting an antenna outside on a pole and running the
coax into the
basement.
nope, not the way to do it right.

Then I would strip back several inches of the outer jacket
of the coax [axposing the braided shield] and connect the coax braid to
the cold water pipe using several hose clamps. This should ground the
coax directly to the service ground - the single point ground for the
house.
except the single point shouldn't be 'inside' the house.

I would add an arrester near the ground point. I would then run
the coax upstairs [about 10 feet] to the radio, where it would [via the
PL-259] connect to the transceiver chassis. The radio chassis will be
electrically bonded to peripheral equipment chassis'.
the radio chassis should be connected to the same single point ground, and
not via just the coax shield.

It seems that in the unlikely event [low altitude, semi-urban area]
that the antenna were struck by lightning, the energy [albeit
significant] would have no reason to propagate up to my station. Even
though it may elevate my house ground by thousands of volts [with
respect to some other ground point], the station should ride up with it
- and little current should flow in the coax at the station.

Am I whistling Dixie?


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

Ahhh...The water pipe must be bonded to the electrical system, but the
main ground must be at the entrance. Here, we have plastic water pipe
all the way to the main from the meter, yet we have to bond the meters
which are metal with plastic running in and plastic running out.

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.

It's really easy to avoid here. We do not have metal piping available
for grounding.
Roger Halstead (K8RI & ARRL life member)
(N833R, S# CD-2 Worlds oldest Debonair)
www.rogerhalstead.com

That has nothing to do with not using an underground metal water pipe
that is present on the premises.
--
Tom Horne

Thomas Horne wrote:


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


Ahhh...The water pipe must be bonded to the electrical system, but the
main ground must be at the entrance. Here, we have plastic water pipe
all the way to the main from the meter, yet we have to bond the meters
which are metal with plastic running in and plastic running out.

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.


It's really easy to avoid here. We do not have metal piping available
for grounding.
Roger Halstead (K8RI & ARRL life member)
(N833R, S# CD-2 Worlds oldest Debonair)
www.rogerhalstead.com


That has nothing to do with not using an underground metal water pipe
that is present on the premises.
--
Tom Horne

that would really depend on the local AHJ (Authority Having
Jurisdiction).. For instance, in the City of Thousand Oaks, CA, only
Concrete Encased Grounding Electrodes (aka Ufer grounds) are allowed in
new construction. (other grounding electrodes are permitted, but you
better have the Ufer ground, and, of course, they would need to be
bonded together, per NEC). With respect to my house, built in 1998, I
don't think there is a bonding jumper from water pipe to the system
ground at the service entrance (which is a Ufer ground). Obviously,
there IS a jumper from the telco drop, the cable TV drop, etc. to the
ground at the service entrance (and all the "drops" are actually
underground services in plastic conduit). Partly this is because the
water service comes in on the opposite of the house from all the "wired"
utilities. I'll have to go take a look, though.

I believe the new code (which I don't have here to hand) does require
that metallic water piping, if any, be bonded to the electrical system
ground (presumably to eliminate "touch voltage").

I believe also, that the code prohibits use of a water pipe as the sole
grounding electrode (NEC 250-(a)(2) in 1999 code, 250.53(D)(2) 2002,2005
codes). As always in code matters, what the AHJ says takes precedence.

As a practical matter, a properly constructed Ufer ground is probably
lower impedance and more reliable than rods, wires, and pipes.

Jim Lux, P.E.
W6RMK

Jim Lux wrote in
:

....
As a practical matter, a properly constructed Ufer ground is probably
lower impedance and more reliable than rods, wires, and pipes.

In this part of the world (Australia) an LV transformer usually serves
many more premises (commonly 50 to 100), and the neutral wire (centre of
the 3 phase 240/415 wye) is bonded to the premises earth electrode at
each main switchboard (known as Multiple Earth Neutral or MEN), so
premises earth systems are effectively paralleled using the neutral wire.
The transformer neutral is connected to an earth electrode at the
substation. The regulatory requirement for a MEN premises ground
electrode here is just a 1.2m copper clad driven electrode, with no real
performance requirement. Of course the earth system must be equipotential
bonded to the metallic water service, and plumbers are at risk when they
open up a metallic water pipe (they are supposed to jumper the gap to
prevent electric shock).

This approach is probably less suited to 110VAC distribution.

Owen

Jim Lux wrote:
Thomas Horne wrote:


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


Ahhh...The water pipe must be bonded to the electrical system, but the
main ground must be at the entrance. Here, we have plastic water pipe
all the way to the main from the meter, yet we have to bond the meters
which are metal with plastic running in and plastic running out.

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.


It's really easy to avoid here. We do not have metal piping available
for grounding.
Roger Halstead (K8RI & ARRL life member)
(N833R, S# CD-2 Worlds oldest Debonair)
www.rogerhalstead.com


That has nothing to do with not using an underground metal water pipe
that is present on the premises.
--
Tom Horne

that would really depend on the local AHJ (Authority Having
Jurisdiction).. For instance, in the City of Thousand Oaks, CA, only
Concrete Encased Grounding Electrodes (aka Ufer grounds) are allowed in
new construction. (other grounding electrodes are permitted, but you
better have the Ufer ground, and, of course, they would need to be
bonded together, per NEC). With respect to my house, built in 1998, I
don't think there is a bonding jumper from water pipe to the system
ground at the service entrance (which is a Ufer ground). Obviously,
there IS a jumper from the telco drop, the cable TV drop, etc. to the
ground at the service entrance (and all the "drops" are actually
underground services in plastic conduit). Partly this is because the
water service comes in on the opposite of the house from all the "wired"
utilities. I'll have to go take a look, though.

I believe the new code (which I don't have here to hand) does require
that metallic water piping, if any, be bonded to the electrical system
ground (presumably to eliminate "touch voltage").

I believe also, that the code prohibits use of a water pipe as the sole
grounding electrode (NEC 250-(a)(2) in 1999 code, 250.53(D)(2) 2002,2005
codes). As always in code matters, what the AHJ says takes precedence.

As a practical matter, a properly constructed Ufer ground is probably
lower impedance and more reliable than rods, wires, and pipes.

Jim Lux, P.E.
W6RMK

Jim
I would hope you are aware that most concrete encased electrodes are
not, in fact, a true UFER. In spite of that it is undoubtedly the most
reliable electrode; which is not to say lowest impedance; commonly
installed in homes. You are correct that an underground metal water
piping electrode must always be supplemented with another electrode but
the code still requires it to be used as an electrode were it is present
on the premise. In my location the public water utility is entirely
metallic, including the service laterals to buildings. It covers about
fifty miles from north to south and more than thirty five miles east to
west at it's widest point. That large an underground metal piping system
has the lowest obtainable impedance to ground of any electrode on a
premise served by the water system.
--
Tom Horne

"Thomas Horne" wrote in message
ink.net...
Roger wrote:
On Mon, 02 Apr 2007 04:08:47 GMT, Thomas Horne
wrote:

Jimmie D wrote:
"Dave" wrote in message
. ..
wrote in message
oups.com...
I would like to propose a grounding arrangement for my [hypothetical]
antenna and get some feedback on it. I have access to the
solid-copper
cold-water pipe that enters my home through the basement wall close
to the basement floor.
bad start

This pipe is used [in addition to cold water] for
the service entrance [circuit breaker box] ground.
thats bad news

I was thinking of putting an antenna outside on a pole and running
the coax into the
basement.
nope, not the way to do it right.

Then I would strip back several inches of the outer jacket
of the coax [axposing the braided shield] and connect the coax braid
to
the cold water pipe using several hose clamps. This should ground
the
coax directly to the service ground - the single point ground for the
house.
except the single point shouldn't be 'inside' the house.

I would add an arrester near the ground point. I would then run
the coax upstairs [about 10 feet] to the radio, where it would [via
the
PL-259] connect to the transceiver chassis. The radio chassis will
be
electrically bonded to peripheral equipment chassis'.
the radio chassis should be connected to the same single point ground,
and not via just the coax shield.

It seems that in the unlikely event [low altitude, semi-urban area]
that the antenna were struck by lightning, the energy [albeit
significant] would have no reason to propagate up to my station.
Even
though it may elevate my house ground by thousands of volts [with
respect to some other ground point], the station should ride up with
it
- and little current should flow in the coax at the station.

Am I whistling Dixie?


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

Ahhh...The water pipe must be bonded to the electrical system, but the
main ground must be at the entrance. Here, we have plastic water pipe
all the way to the main from the meter, yet we have to bond the meters
which are metal with plastic running in and plastic running out.

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.

It's really easy to avoid here. We do not have metal piping available
for grounding.
Roger Halstead (K8RI & ARRL life member)
(N833R, S# CD-2 Worlds oldest Debonair)
www.rogerhalstead.com

That has nothing to do with not using an underground metal water pipe that
is present on the premises.
--
Tom Horne

Sure it does, what happens when a plumber replaces a piece of metal pipe
with plastic and opens your ground. The plumber has no responsibility to see
if the plumbing is being used for ground. Mrtal plumbing should be bonded to
the electrical ground, not be the ground.