wrote:
On Nov 27, 8:46 pm, Dave Heil wrote:
James Barrett wrote:
Does it really matter if my equipment is ground to the house ground or
should it really be connected to its own external ground? And if/when
I ground to guard against lightning strikes, would I use that same
external ground or go with yet another external ground?
I'm still doing my research, but figured it couldn't hurt to ask.
Jim,

You'll see numerous references on the web to "single point ground." It
is very, very important stuff. I got nailed on this stuff back in
August, 2003. Here's how it played out:

We had a violent thunderstorm early one morning about 7 A.M. Suddenly
there were three near strikes (simultaneous lightning and thunder)
within a ten second time frame. In addition to telephones, computers
and home entertainment equipment, my four month old Ten-Tec Orion and
numberous shack accessories were zapped. My house ground is a single 8
foot copper plated ground rod. The lightning ground for the shack was
an identical ground rod driven about thirty feet away from the house ground.

When the strikes conducted a surge into my home via the power lines, all
three wires had very high voltage on them. The shack ground was still
at its usual potential (0). The house ground was elevated to high
voltage. There was a potential difference between the shack ground the
the house ground. That potential quickly equalized inside my equipment.

Ten-Tec reported that six boards inside the Orion had their ground
traces evaporated.

For a shack ground, you want the shortest possible distance between your
rig and earth. The house ground will be as close as possible to your
electrical service entrance. If, like me, you have to use two ground
rods, you need to bond the two of them together with a big, fat wire so
that the two can never be at different potentials.
If you have a tower, I'll assume that you have at least one 8 foot
ground rod driven at its base. Bond your coaxial cable sheaths to the
rod at the tower. The sheaths should also be bonded to your shack ground.

Dave Heil K8MN

This whole topic area seems to be eternally confused and confusing and
I'm in the parade of the confused. On a common sense basis I
absolutely agree with your connecting the station grounds to the
'lectric service entrance ground for the reasons you've stated.

But somewhere along the line somebody in the ham groups stated that
the National Electrical Code states that there shall be one and *only
one* grounding point per power drop and the neighborhood code cops and
the insurance companies reportedly get stiff about it.

So is it legal to connect a phalanx of ham station ground rods to the
service entrance ground?? Or not.


w3rv


What the code enforcement types get vexed about is were you have two
different Grounding Electrode Systems (GES) that are not bonded together
into a single system. So if you have one concrete encased electrode in
your tower base, another concrete encased electrode in your homes
footer, and a driven rod array electrode just outside the radio room
wall and you do not bond them together into a single GES that is a code
violation. It is also a code violation to connect any conductor that
carries power and light current to ground at any point in the wiring
system that is not at the Service Disconnecting Means (SDM). The SDM is
the first switch, breaker, or fused pull out that can be used to
disconnect the ungrounded current carrying conductors of the wiring
system from the service entry conductors. In most homes this is the
main breaker or the main fuse pull out. The code name for the white
wire in North American wiring practice is the "Grounded Current Carrying
Conductor." In many cases it is also the neutral conductor but that is
not always the case. It is that white wire that most of us call the
neutral; albeit sometimes mistakenly; that must be connected to the GES
at one and only one point. That point is the portion of the service
entrance grounded conductor that is between the splices that connect it
to the utility company's conductors and the SDM.

A practice that was very popular in the computer industry was to ground
the computer equipment power supplies of main frame computers to a new
and separate grounding electrode at the computers location. Connecting
that ground back to the power service ground was carefully avoided on
the belief that doing so would cause ground loops on the signal circuits
between the main frame and the associated terminal equipment. Some self
qualifying authorities recommended the same approach for radio
equipment. That left the earth between the two electrode systems as the
only return path for current faulting to ground at the improperly
isolated ground equipment. With the resistance to earth of most driven
rod electrodes being over fifty ohms the series resistance of such a
fault current pathway was often over a hundred ohms. Such a high
impedance would limit the fault current flowing back to the utility
transformer from whence it came to a flow too small to trip the Over
Current Protective Device (OCPD) protecting the faulted circuit. You
then have a situation in which all of the exposed conductive parts of
the radio or computer equipment is energized at 120 volts relative to
earth or any body that will behave as the earth does electrically.
Since it only takes about a third of an ampere to kill a human being the
user could be electrocuted without ever tripping the OCPD. Because the
danger to life was of a greater concern to code authorities then the
difficulties caused by ground loops on signal lines the electronic
engineers lost that war with the electrical engineers and the rule
forbidding separate grounding electrode systems survived the attempts to
remove it from the nations electrical codes.

The good news for us as amateur radio practitioners is that what is safe
is also good operating practice. By bonding all of our grounding
electrode systems together into a single system we get a better ground
for most purposes and we greatly decrease the likelihood of equipment
damage or operator injury / death.
--
Tom Horne

"This alternating current stuff is just a fad. It is much too dangerous
for general use." Thomas Alva Edison

"James Barrett" wrote in message
...
Hi, I did some searches on google for grounding, but all the
information I have found talks about grounding antennas and such
against lightning strikes. But the grounding I am interested in
researching is the type of ground I would use on my HF radio, power
supply, and antenna tuner. I haven't grounded anything yet, but I
would like to. I seem to have a hazy recollection of reading somewhere
that I should use copper braid and connect it to the house ground.
But during my search I found this image (which basically sums up the
article it came from ) http://www.qsl.net/n5nj/kuby/image16.gif

Does it really matter if my equipment is ground to the house ground or
should it really be connected to its own external ground? And if/when
I ground to guard against lightning strikes, would I use that same
external ground or go with yet another external ground?

I'm still doing my research, but figured it couldn't hurt to ask.

Thanks!

Jim
my own experence is that using the household ground at hf is marginal at
best

my own result were greatly inproved with aan extrenal seperat e ground

Hi James,

There are several good articles at the www.eham site on this very subject.
If you can read between the lines of some of the muck slinging, you can come
up with several really good solutions.

Just click on the "view more articles" link [at the top of the horizontal
green separator] HTH.

Alain



"James Barrett" wrote in message
...
Hi, I did some searches on google for grounding, but all the
information I have found talks about grounding antennas and such
against lightning strikes. But the grounding I am interested in
researching is the type of ground I would use on my HF radio, power
supply, and antenna tuner. I haven't grounded anything yet, but I
would like to. I seem to have a hazy recollection of reading somewhere
that I should use copper braid and connect it to the house ground.
But during my search I found this image (which basically sums up the
article it came from ) http://www.qsl.net/n5nj/kuby/image16.gif

Does it really matter if my equipment is ground to the house ground or
should it really be connected to its own external ground? And if/when
I ground to guard against lightning strikes, would I use that same
external ground or go with yet another external ground?

I'm still doing my research, but figured it couldn't hurt to ask.

Thanks!

Jim

Joaquin Tall wrote:
Hi James,

There are several good articles at the www.eham site on this very subject.
If you can read between the lines of some of the muck slinging, you can come
up with several really good solutions.

Just click on the "view more articles" link [at the top of the horizontal
green separator] HTH.

Alain



"James Barrett" wrote in message
...
Hi, I did some searches on google for grounding, but all the
information I have found talks about grounding antennas and such
against lightning strikes. But the grounding I am interested in
researching is the type of ground I would use on my HF radio, power
supply, and antenna tuner. I haven't grounded anything yet, but I
would like to. I seem to have a hazy recollection of reading somewhere
that I should use copper braid and connect it to the house ground.
But during my search I found this image (which basically sums up the
article it came from ) http://www.qsl.net/n5nj/kuby/image16.gif

Does it really matter if my equipment is ground to the house ground or
should it really be connected to its own external ground? And if/when
I ground to guard against lightning strikes, would I use that same
external ground or go with yet another external ground?

I'm still doing my research, but figured it couldn't hurt to ask.

There are two grounds for your radio system. There is an RF ground, and
there is a power ground. They aren't the same, and even the term
"ground" is a little nebulous. But it is convention.

Dealing with the Power ground, you'll want to tie the grounds on the
back of your radios/tuners/amplifiers together. There are a number of
ways to do this. Some folks construct a copper ground plane that has
wires running to it from the equipment needing grounded.

Another possibility is wiring to the grounding bars such as are used for
electrical service. This is the method I use.

Whatever method used, short wires are better working practice.

I'll just go over my own setup as beyond the grounding bar, you'll get a
lot of opinions on what is right. I run heavy gauge wire out to a 8 foot
copper pipe embedded about 7.5 feet into the ground, and have ground
clamps to attach it. Braid is good too.

Some other thoughts:

I install the pipe hydrostatically - I sweat a garden hose adapter onto
the copper pipe, attach a hose to it, and let 'er rip (hopefully no
disclaimers needed here) The water digs a hole for the pipe, which then
sinks into it. It's fun

some folks ground to a water pipe. Not a good idea, as modern plumbing
does not always have continuity - there might be a piece of PVC in the
line somewhere.

I have my Arrester going to that pipe also. I'm using a "spark gap" type
arrester, but I would really recommend one of the gas discharge types.
They are quick to respond, and better protection in general.

Hope this helps.

- 73 de Mike N3LI -

Michael Coslo wrote:
There are two grounds for your radio system. There is an RF ground, and
there is a power ground. They aren't the same, and even the term
"ground" is a little nebulous. But it is convention.

The is probably the biggest point of confusion for me. What do you mean
by "RF ground"? The type of ground I was asking about is the ground
terminal on the back of my radio,not the three prong power plug. There
is the ground terminal on the back of my radio and there is also a
ground terminal on my power supply, even though both have three prong
power plugs. So, are the ground terminals on the back of my radio and
power supply called RF ground, or are the called Power ground? Because I
thought that the power ground was the three prong plug.


Jim

In article ,
James Barrett wrote:

The is probably the biggest point of confusion for me. What do you mean
by "RF ground"? The type of ground I was asking about is the ground
terminal on the back of my radio,not the three prong power plug. There
is the ground terminal on the back of my radio and there is also a
ground terminal on my power supply, even though both have three prong
power plugs. So, are the ground terminals on the back of my radio and
power supply called RF ground, or are the called Power ground? Because I
thought that the power ground was the three prong plug.

The intent of the third prong on the power plug is to provide a safe
path from the equipment chassis, back to the power panel (where the
neutral and hot are bonded together). This ensures that if there's a
fault inside the equipment, and a "hot" wire touches the chassis, the
stray current will immediately flow back to the panel via this ground
connection (and likely cause a fuse to blow or a breaker to trip very
quickly). It ensures that you don't end up with a chassis which is
"hot", and isolated from ground... just waiting for somebody to touch
it, accidentally complete a path to ground via their body, and get
themselves mildly dead.

The intent of the ground terminal on the back of the radio is to let
you tie the radio chassis to a good RF ground, so that if any RF
reaches the chassis via conduction (e.g. coming back down the
feedline) it doesn't leave you with a chassis which is RF-hot compared
to grounded objects nearby (this could cause an RF burn if you touch
the chassis, or sneak back into the microphone wiring and cause weird
squawking sounds when you transmit). It's also necessary if you plan
to use a random-wire or similar unbalanced antenna which is designed
to work against the station ground (e.g. radials or counterpoises).

It's normally the practice to bond *all* of the equipment in your
shack together with good (short, heavy) grounding wire or braid...
once again, ensuring that different pieces of equipment have their
chassis at the same (or nearly the same) AC and RF potential. By
doing so, you are in effect bonding together your power/safety ground,
and your station RF ground, creating a single ground system.

Because this in-the-station ground bonding isn't really designed to
handle massive amounts of fault current (e.g. from lighting) and since
it's in an area where you really don't want such fault current to flow
(e.g. your shack), it's still important to bond your station's "RF
ground" rod, and your house's service-panel ground rod, together as
per NEC.

--
Dave Platt AE6EO
Friends of Jade Warrior home page: http://www.radagast.org/jade-warrior
I do _not_ wish to receive unsolicited commercial email, and I will
boycott any company which has the gall to send me such ads!

Dave Platt wrote:

The intent of the third prong on the power plug is to provide a safe
path from the equipment chassis, back to the power panel (where the
neutral and hot are bonded together). This ensures that if there's a
fault inside the equipment, and a "hot" wire touches the chassis, the
stray current will immediately flow back to the panel via this ground
connection (and likely cause a fuse to blow or a breaker to trip very
quickly). It ensures that you don't end up with a chassis which is
"hot", and isolated from ground... just waiting for somebody to touch
it, accidentally complete a path to ground via their body, and get
themselves mildly dead.

One of the reasons that Ground fault interrupters are around. If you
have a hundred feet or even more of neutral wire going back to that
panel, you can still get an appreciable current flowing through you
without tripping a breaker. I've had my tookus saved by one of those
GFCI things when a power tool failed in the manner you just described. I
felt the shock for just a fraction of a second, then it tripped.



the chassis, or sneak back into the microphone wiring and cause weird
squawking sounds when you transmit).

Ahh, that happens to me all the time even without RF on the mic! ;^)


- 73 de Mike N3LI -

On Fri, 30 Nov 2007 02:08:18 EST, (Dave Platt)
wrote:

The intent of the third prong on the power plug is to provide a safe
path from the equipment chassis, back to the power panel (where the
neutral and hot are bonded together).

You do mean the neutral and ground, right?
--

73 de K2ASP - Phil Kane

From a Clearing in the Silicon Forest
Beaverton (Washington County) Oregon

e-mail: k2asp [at] arrl [dot] net

James Barrett wrote:
Michael Coslo wrote:
There are two grounds for your radio system. There is an RF ground, and
there is a power ground. They aren't the same, and even the term
"ground" is a little nebulous. But it is convention.

The is probably the biggest point of confusion for me. What do you mean
by "RF ground"?

It is confusing, so you're not alone.

RF grounds can be related to Power grounds, but only so far. On say a
ground plane antenna, where you have a vertical center rod connected to
the coax center conductor, and some angled rods connected to the coax
shield, those angled rods are serving as a ground plane. They aren't
connected to actual earth.

This is where a lot of the confusion comes in. The ground plane is more
of a counterpoise, or to look at it as a circuit, a place for the other
part of the current to go.

Now if we look at say a vertical HF antenna of the 1/4 wave variety,
typically this antenna will have "grounding" by way of many radial
lengths of wire that are either buried in the earth at a shallow depth,
or even just stapled to the surface of the earth.

This is "Kind of-sort of" like a power ground, in that it is in the
earth, but its doing something different. It is operating very similarly
to that ground plane. It gives the RF current a place to go.

I didn't go into things like impedence to avoid confusing the issue, but
that would be next in the discussion.



The type of ground I was asking about is the ground
terminal on the back of my radio,not the three prong power plug. There
is the ground terminal on the back of my radio and there is also a
ground terminal on my power supply, even though both have three prong
power plugs. So, are the ground terminals on the back of my radio and
power supply called RF ground, or are the called Power ground?

The ground terminals on your equipment are part of the power ground,
that you would attach to the pipe in the yard. Explanation of that
below. Any RF ground would be considered to be on the shield of the coax
connectors.

Because I
thought that the power ground was the three prong plug.

Yes, generally. One of the reasons that we put in a separate ground rod
from house ground for a power ground is that there can be currents on it
after going around the house. It's still mostly neutral, but with
hundreds of feet of that green wire running around the house, you can
still get some currents.


Some people can "get away with" not having a station power ground.
Kinda. I highly recommend one especially for some place to send your
lightning protection.

- 73 de Mike N3LI -

The National Electrical Code (NEC) specifies that there be two
grounding points for a residential system. That can mean either two
ground rods, six feet apart, connected to the panel with a continuous
loop of wire, or a single ground rod in cases where there is municipal
water, and the second ground source is the water main coming in, on
the road side of the meter. The gas line also needs to be grounded to
the panel.

In the main service panel, the grounding system is attached to the
same buss as the bare neutral coming in from the transformer. If your
shack is running off a sub-panel, it should be fed with four conductor
cable. In this case an insulated neutral is used and the bare (or
insulated, it doesn't matter in this instance) ground is connected to
a separate equipment ground buss. If your shack is in a separate
structure that has its own sub panel, it needs to be fed with three
conductor ground, the neutral is connected to the ground bar and a
ground wire from a single ground rod is connected to the same buss
(similar to the setup at the main panel). It sounds confusing as
written here, and it's even more confusing to read it from the NEC,
but I just had this out yesterday with my local inspector while going
over the fine points on a job.

All that NEC stuff is important to check to make sure you're setup is
electrically safe. As for station grounding, it's not usually a good
idea to use the electrical system ground rods for your RF grounds.
Your rig, tuner, amps, etc, should all be grounded to a single buss
with the shortest possible wires, then a large chunk of wire, #6 or
better, should run as directly as possible to a separate 8' ground
rod. If you have a tower, you should drive at least one 8 footer at
the base and ground it there. There's no limit to the number of ground
rods you can have for RF grounds, they're less than $10 from a
distributor and well worth the effort. I've heard of hams setting up
verticals with very minimal radials, just driving several ground rods.

But somewhere along the line somebody in the ham groups stated that
the National Electrical Code states that there shall be one and *only
one* grounding point per power drop and the neighborhood code cops and
the insurance companies reportedly get stiff about it.

The answer to that is that if there is more than one they must be
connected. The methods differ depending on the location of services in
the structures and around the property. An electrician following the
NEC would have done this during the installation and (hopefully) the
inspector would have signed off on it. Ground rods for RF equipment
SHOULD NOT be connected in any way to the electrical system ground
rods.

73
KC2PNF
Jon Dayton