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. This pipe is used [in addition to cold water] for
the service entrance [circuit breaker box] ground. I was thinking of
putting an antenna outside on a pole and running the coax into the
basement. 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. 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'.

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?

Thanks,

-JJ

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?

wrote:
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. This pipe is used [in addition to cold water] for
the service entrance [circuit breaker box] ground. I was thinking of
putting an antenna outside on a pole and running the coax into the
basement. 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. 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'.

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?

Thanks,

-JJ


I'm sure not an expert on the subject but ARRL ran a good multipart
series in 2002 that might address some of your questions.

http://www.arrl.org/tis/info/pdf/0206056.pdf
0206056.pdf (application/pdf Object)

Good luck!

Chuck

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Maybe read PolyPhaser | The Authority On Lightning & Surge Protection

http://www.polyphaser.com/

Happy New year -- CL

try

http://www.w8ji.com/ground_systems.htm

bob

On 1 Jan 2007 04:40:29 -0800, "
wrote:

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

Hi OM,

You have the classic service ground connection.

I was thinking of
putting an antenna outside on a pole and running the coax into the
basement. 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 qualifies, in most respects, to code for grounding a continuous
wire and employing a method prescribed by code, clamping. However, it
would seem that clamping might deform the coax. You should
investigate your local code for alternatives as well as for
compliance.

This should ground the
coax directly to the service ground - the single point ground for the
house. I would add an arrester near the ground point.

Then you are breaking the run instead of just simply stripping the
jacket. Check code.

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'.

This is also classically known as a suicide connection. If you were
holding the PL-259 shell in one hand, and touched any, poorly
maintained metal chassis of the transceiver while plugging it in (or
removing it); then you might just be the fuse in a circuit about to
blow. I've seen my buddy draw sparks with just such an arrangement
before I convinced him to run a real, separate ground.

73's
Richard Clark, KB7QHC

" wrote in
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

You haven't described here the antenna and its support structure, and
they are relevant.

One of the strategies for hardening a site against lightning is to divert
as much of the strike current to ground rather than having it flow in the
conductors within the facility. The value / necessity of this measure
will depend on the antenna, its support structure, nearby structures that
might protect your antenna to some extent, and the risk of lighting in
your locality.

cold-water pipe that enters my home through the basement wall close to
the basement floor. This pipe is used [in addition to cold water] for
the service entrance [circuit breaker box] ground. I was thinking of
putting an antenna outside on a pole and running the coax into the
basement. 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. 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'.

Lightning conductors need to be substantial enough to withstand the
strike scenario without physical failure (eg melting). A common scenario
is 20kA for 0.1s, but it does depend on the situation. Is your coax braid
and your termination / bonding method sufficient to survive strike
current?

Equipotential bonding of the lightning protection ground and the AC
service ground systems is important. Low resistance and more importantly
low inductance conductors that will withstand the current are required.

Depending on your coax shield as a bonding conductor from your equipment
to the ground point as you describe sounds unwise for several reasons,
but most notably because it uses coax connectors (and probably PL259s at
that) for the connection, they are not reliable enough, and they would
not be a permanent connection).

If your equipment runs on low voltage DC, do not assume that the power
supply provides a connection between the AC ground and the -ve DC lead,
some powersupplies have floating output. In any event, bonding of the
external metal of all equipment in your station to a single point ground
is advisable to reduce the risk of substantial potential differences
between equipments, and the risk that poses to life in the event of
lightning or even an electrical fault.

If addressing these issues seems extreme, it is probably a good indicator
that many ham station earth systems are quite inadequate, offset by the
low probability of an adverse event and not usually talked about when
poor implementation exacerbated the situation.

Like one of the other respondents, I recommend the Polyphaser site, it is
a usefull source that canvasses many of the issues.

Additionally, your wiring codes or standards may provide guidance or set
requirements, they do here.

Having done all that, and with better knowledge, review the risk, cost
and measures. You may not want to resource a lightning hardened solution
for 24x7 connection of the stations to antennas.

Owen

"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

"Caveat Lector" wrote in message
...
Maybe read PolyPhaser | The Authority On Lightning & Surge Protection

http://www.polyphaser.com/

Happy New year -- CL


THE BIBLE on grounding and bonding.as far as I am concerned.

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



Electrical service grounding via water pipes is common and acceptable.
Quoting from the 2005 NEC, which is the standard used in many or most
jurisdictions in the US:

250.52 Grounding Electrodes.
(A) Electrodes Permitted for Grounding.
(1) Metal Underground Water Pipe. A metal underground water pipe in
direct contact with the earth for 3.0 m (10 ft) or more (including any
metal well casing effectively bonded to the pipe) and electrically
continuous (or made electrically continuous by bonding around insulating
joints or insulating pipe) to the points of connection of the grounding
electrode conductor and the bonding conductors. Interior metal water
piping located more than 1.52 m (5 ft) from the point of entrance to the
building shall not be used as a part of the grounding electrode system
or as a conductor to interconnect electrodes that are part of the
grounding electrode system.


I agree this is not a good solution for lightning protection.

73,
Gene
W4SZ