Acceptable Lightning Ground?
 

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

Acceptable Lightning Ground?
 

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

Acceptable Lightning Ground?
 

On Apr 2, 8:07 am, Roger wrote:
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'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

Roger is correct here. Underground water pipe electrode is no
longer sufficient as the earth ground in most locations for a long
list of reasons. Yes, that water pipe must be bonded to the AC
electric so that plumbing is electrically same voltages as everything
else inside the house - human safety. Public utility water system may
have voltages different from AC electric if the two are not bonded -
as has been observed when a fault was created outside the building.
Destructive currents entering on that water system must be eliminated
by being bonded to AC electric.

Many other reasons why AC breaker box must be bonded to the cold
water pipe. Yes cold water pipe may act as an earthing electrode.
But it is no longer sufficient as the earthing electrode.

An earthing electrode - one that all utilities must use - is not the
water pipe. All utilities must connect to a separate and dedicated
earthing electrode defined by code (as defined in Article 250.52 A -
paragraphs 2 through 7). The code defines 7 types of earthing
electrodes. The only electrode not sufficient is cold water pipe -
paragraph 1.

For lightning, an antenna (or satellite dish) is typically treated
as if a separate structure as demonstrated in this application note:
http://www.erico.com/public/library/...es/tncr002.pdf
Antenna wire must connect to the same building 'single point' earthing
electrode. IOW any wire in any cable going to the station must first
connect to that single point earthing electrode (either by hardwire or
protector) before entering the building. Best is to have the antenna
earthing also connected, by underground wire, to that same single
point ground.

This for lightning protection is beyond what is called for by
National Electrical Code for numerous reasons. First, NEC only
addresses human safety. The OP is asking about transistor safety.
Second, the code does little to address impedance. Grounding for
human safety is mostly about resistance - not impedance. Third, any
grounding system dependent on some other trade (ie plumber) is no
longer considered safe or sufficient.

A ground system must meet NEC requirements. Then it must exceed
those requirements. For lightning protection, a cold water pipe is
not longer considered a good solution because that earthing electrode
is just not sufficient.

Also better is to earth lightning rods and antennas before that
ground wire connects to a building's single point ground. Notice the
underground wire connection between antenna earth ground and building
earth ground.

And finally a purpose of earthing that is beyond what the NEC
requires. A station needs earthing that provided both equipotential
and conductivity. Code concentrates on conductivity. But for
equipotential, we do things beyond what is normally sufficient for
human safety. We install Ufer grounds or halo grounds that completely
surround the protected facility. We relocate all utilities so that
each wire in each cable makes a 'less than 10 foot' connection to that
common earth electrode. Any exception to the single point earth
ground (as defined in code) is not permitted when also earthing for
transistor safety. Route earthing wires to be separate from all other
wires, no splices, no sharp bends, not inside metallic conduit, etc.
All earthing wires remain electrically separate until all meet at the
single point ground. Conditions beyond what code demands or permits.

Consider with care information in that figure in:
http://www.erico.com/public/library/...es/tncr002.pdf
Things recommended are not immediately obvious. Reasons for this
involve both equipotential and conductivity. Both are required for
station protection.

Acceptable Lightning Ground?
 

w_tom wrote:

On Apr 2, 8:07 am, Roger wrote:

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'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


Roger is correct here. Underground water pipe electrode is no
longer sufficient as the earth ground in most locations for a long
list of reasons.

As Thomas said, Roger is correct if the underground water service pipe
is plastic.
Missing is any of the “long list of reasons”.


Many other reasons why AC breaker box must be bonded to the cold
water pipe. Yes cold water pipe may act as an earthing electrode.
But it is no longer sufficient as the earthing electrode.

An earthing electrode - one that all utilities must use - is not the
water pipe. All utilities must connect to a separate and dedicated
earthing electrode defined by code (as defined in Article 250.52 A -
paragraphs 2 through 7). The code defines 7 types of earthing
electrodes. The only electrode not sufficient is cold water pipe -
paragraph 1.

The code says (250.50) all electrodes listed in 250.52-A-1 through 6
MUST (where present) be connected together to form the earth electrode
system. 250.52–A-1, which is conveniently missing from w_’s list, is
metal underground water pipe (at least 10 feet metal underground).

ONLY if the pipe is not 10 feet long underground is bonding used instead.

Water pipe requires a “supplemental” electrode. That is because the
metal pipe may in the future be replaced by plastic.
From the National Electrical Code Handbook - same publisher as the NEC
“The requirement to supplement the metal water pipe is based on the
practice of using plastic pipe for replacement when the original metal
water pipe fails. This leaves the system without a grounding electrode
unless a supplementary electrode is provided.”

Requiring a supplemental electrode does not indicate there is any defect
in metal pipe as an electrode. As Thomas indicates, it is likely by far
the best electrode available in urban areas with metal supply.

Earthing connection of other services, like the phone NID, may be made
to the water pipe within 5 feet of the entrance to the building (the
connection of the power earthing conductor is in the same 5 foot span).



We install Ufer grounds or halo grounds that completely
surround the protected facility.

From
http://www.lightningsafety.com/nlsi_...finitions.html
“Halo Grounded Ring: A grounded No. 2 wire, installed around all four
walls inside a small building, at an elevation of approx. six inches
below the ceiling. There are drops installed from the halo to the
equipment cabinets and to waveguide ports, interior cable trays etc.
Halo rings serve as connector points to achieve ground references of
interior metallic objects. These, in turn, are connected to the main
ground bus bar.”

Perhaps you mean “ground ring”?


----------------
The code now requires a Ufer electrode in new construction with concrete
foundations or footings.

--
bud--

Acceptable Lightning Ground?
 

Dave wrote:
"I would like to propose a grounding arrangement for my (hypothetical)
antenna and get some feedback on it."

Assuming the tower is not base insulated, start by grounding each leg of
the tower with a no. 6 AWG or larger cable directly to its own ground
rod.

Best lightning protection comes from folded driven element antennas
grounded directly at the tower top or other mounting point and
connecting the antenna with coax which is grounded again at the tower
base. If a folded driven element is not used, a short-circuited
quarter-wave stub can be connected directly across the antenna
drivepoint to supply the grounding to the tower that a folded element
provides.

Standard practice requires a no. 6 AWG or larger cable directly
connecting the base of the tower to the ground connection used by the
electrical service to the site.

For enhanced protection, large RF chokes as used in tower lighting
circuits in broadcast stations, are placed in each power wire, including
the neutral, between the electrical service and the radio connected to
the antenna. A-C capacitors are connected between each end of the
high-current chokes and a common connection directly to the station
ground. If there are 3 wires you need 6 caoacitors. Across each
capacitor you need a metal oxide varistor appropriate for the line volts
and the joules you may be called upon to dissipate when lightning
strikes. We also shunted the capavcitors with conventional thyrite
arrestors to back-up the MOV`s. This pi-filter with arresters worked
like gang busters. It is not excessive but did prove necessary for
solid-state equipment protection.

Best regards, Richard Harrison, KB5WZI

Acceptable Lightning Ground?
 

"Thomas Horne" wrote in message
link.net...
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 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)..

Acceptable Lightning Ground?
 

"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.

Acceptable Lightning Ground?
 

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--

Acceptable Lightning Ground?
 

"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

Acceptable Lightning Ground?
 

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