I recently had an electrician verify that I need a new grounding rod but
before he does the work I wanted to get clear regarding the manner in which
telephone, cable, roof mounted TV antenna, and water pipes should be
grounded to the main service ground.
The rod will be planted a few feet from the house just opposite the inside
service panel. Must the TV Antenna ground go all the way to the top of the
rod or is it okay to split-bolt to the grounding wire at or just below
The main water pipe enters the house about 25 yards away from the grounding
rod. Is it acceptable to ground the cold water pipe to the service ground
from inside the house? In this case I would split-bolt to the service
ground wire just before it goes through the basement wall.
My house is cabled for cable TV (although I don't currently subscribe).
Where is the best (practical) place to ground the TV Cable? Split-Bolt
again to service wire as it leaves basement?
Finally, what about Telephone system ground? Split-bolt as it leaves
basement? Is this something the phone company must do (for demarcation
reasons) and if so, are they gonna charge me for it?
Yes, the electrician answered these questions for me already, but my
newsgroup search shows that answers vary and that sometimes the "pros" don't
always do things 100% right, so that's why I've come back here to trusty old
Thanks for your thoughts.
Your safest guide is the local municipal
licensing office which authorizes (and
perhaps inspects) new electric installations.
Carlsbad Springs (Ottawa, Canada)
Thomas D. Horne has accurately summarized important points
as required by code. However effective earthing exceeds
code. Every incoming utility must make a less than 10 foot
connection where they all meet at your new central earth
ground rod. That includes connections from cable ground
block, from TV antenna and satellite dish wires before
entering building, and ground wire from telco supplied surge
protector in NID premise interface box. All earthing wires
must also be direct (not via other wires, no sharp bends, no
splices), and independent (not bundled with other non
grounding wires and separate from all other earthing wires
until they all meet at central earth ground). An old
expression that says a better ground is not neat. No clean
sharp bends. If an angled wire to earth ground is shorter,
then angle the wire rather than make it look clean, sharp, and
TV antenna is suppose to be earthed at shortest point. If
TV antenna is earthed by a separate ground rod, then a buried
solid copper wire (as sized according to code) must
interconnect that separate rod with the main central earth
If soil is non-conductive, than additional rods should be
attached to that central earth ground rod. Central earth
ground must be the best earthing point in the facility.
Poorly conductive soil includes sand, loom, gravel, or soils
bleached of ionic materials.
Some examples of how the earthing system should be
Of course, the grounding system must comply with what Thomas
D. Horne has posted since we earth for multiple reasons - one
is demanded by cited code.
Water pipe is safety grounded - not necessarily earth
grounded. Connection from water pipe must be to breaker box
safety ground bar because that ground wire is to remove
dangerous currents from the water pipe - a human safety
Mark Wilson wrote:
Thanks for the help Thomas D. Horne and everyone else. Sorry about the
cut&paste manner in which I'm responding. I'm having newsgroup trouble.
The guy helping me is a retired electrician. We're waiting on the gas
company to label the gas lines before pounding the rod in the ground. Given
your answers I can see you're being more techincal and accurate than he was,
which is good! It's my job to go pick up the parts we'll need to do the
Thanks I understand, (assuming the EGC is just a fancy way of saying
ing-rod.) I'll use a split bolt to ground the outside TV antenna ground
conductor to the EGC after the EGC leaves the basement but before it reaches
the ground rod.
Thanks for clearing that up. I'll bond the water pipe to the bus bar in the
service panel, and then run the main ground EGC from that same bus bar to
the ground rod. (Techincally, for the main EGC, I'll use the bolt-like
attachement provided at the bottom of said bus bar) Because I'll be
replacing the main EGC with fresh 4 gauge conductor, I'll probably just use
some extra 4 gauge for the pipe to bus conductor as well.
Thanks to you and "w_tom", I see I may be referring to something different
when I say TV cable ground. After the cable enters the house, it goes to a
standard RCA splitter and it's from there that there is some kind of bleed
off ground wire. It was this ground wire that I was referring to rather
than something coming off a block outside the house. Right now the plan is
to just split bolt the cable ground wire to the EGC just before it heads
outside through the basement wall. I'll will have a look at the outside
block for the TV Cable.
(assuming six feet means six meters as was corrected earlier)
The six meters is no problem as the telephone line enters the house right
next to the service panel. However, I'm a little confused by what is meant
by "Service's accessible grounding means". "Accessible" being the key
word, I'm assuming you mean that Telco will ground to the EGC after exists
the service panel, but before it heads outside through the basement wall.
Hmm. Assuming this section "IV" is referring to the EGC, are you saying that
the main ground conductor must be insulated? And by insulated does that
mean plastic wire covering? I thought I'd be safe with a bare solid copper
4 gauge wire? I must be reading this wrong...
Again, although this specifies 14 as the smallest, even 10 or 8 seems too
small. Maybe this part of the code is not referring to the main EGC?
It's very kind of you to take the time to respond, Mr. Horne. If you'll
indulge me in a little further clarification, I'd appreciate it all the
more, but I'm already plenty grateful at this point.
Ground block is really nothing more than a connector that
attached to CATV cable and that permits a 10 AWG ground wire
to be connected. It is even sold in Home Depot with other
CATV cable accessories. Best to put grounding block on cable
outside building and as close to new ground rod as is
possible. Make distance from CATV to ground rod shorter with
minimal bends, etc. Yes that grounded RCA splitter
accomplishes same for human safety and NEC reqirements. But
transistor safety wants that connection to earth ground to be
closer to central earth ground. Also an outside ground block
to ground rod connection makes it easier to keep that ground
wire separate from other non-grounded wires.
Telco provides a "Service's accessible grounding means" in a
box called NID. Their 10 AWG earth ground wire connects their
NID box mounted outside (so that it is accessible) to that
earth ground rod. Some installers want to make that 10 AWG
wire look neat. They will even 'split bolt' attach it to the
breaker box ground wire. However better trained installers
will run their ground wire directly to the top of that ground
rod - as should be the CATV wire ground. All grounds should
run indepenently until they all meet at central earth ground.
This last requirement is not required in code but creates a
more robust and effective earth ground.
As a reminder to others, smart move to have all utilities
located before pounding down the rod.
Mark Wilson wrote:
There is no such thing as a "central earth ground" unless only _one_
grounding electrode is used.....a very poor practice in itself (with the
possible exception of a metal well casing)....much better to have _multiple_
grounding electrodes bonded together. All grounding electrodes are bonded
together to form a _single_ grounding electode _system_. The ground rod
that is being installed is merely a _supplement_ to the main grounding
electrode.......in this case the metal water pipe. Not a good idea to try
to dump all that on a single ground rod.......a single ground rod will in
fact become a choke to lightning trying to get into the ground. That single
ground rod should be supplemented by at least another ground rod 6 feet away
(or use a delta ground), or a ground ring can be installed with a minimum
#2.....and catch the cable TV while you are at it.
The basic idea is too run an unbroken GEC from the main panel to the
underground water pipe (min. #4) and suppliment that with a ground rod (or
two). Then bond all systems together. The idea is that when all the
systems are bonded together, ALL will come up to the same voltage (can be ma
ny thousands of volts), thus _not_ allowing a destructive current flow in
equipment served from different systems....like a modem. Don't forget to
jumper around the water meter and bond the hot water.
Bottom line, electric system grounding is a very misunderstood subject and
needs to be done by people who know and care about how to install it.
You still have your inside metal gas line to deal with.......you should call
your gas co. to see if they allow an (inside) connection to the electric
grounding system as required by NEC.
I hope that after going through all that trouble that you are also going to
install a lightning arrestor at the electric meter or service panel. Then
use a decent point of use surge protector for the computer that has
provision for power _and_ phone....cable too if you ever use a cable modem.
Also, since you said that you have a subpanel in another thread, you should
check to see that the subpanel is fed from the main panel with a _4_ wire
feeder (2 hots, neutral, equipment ground).
Thanks for your help Tom. I also explored the links you provided and found
them helpful. In fact, part of the reason I started looking into this is
because I have lost a modem. Although I have no reason to believe there
have been multiple grounds in the past, I'll be sure everything goes to the
same place before I'm done.
Hmm. Well, I checked and there's no ground whatsoever coming off the CATV
line at the point it enters the house. I'd have to install a new one
outside in order to run a ground line from the entrance point, and that side
of the house is the exact opposite of where I plan to put the ground rod.
The CATV comes from the street to the top of my house and then runs down
before meeting a splitter and entering the house. Becuase I don't currently
subscribe to Cable (and don't plan to), I think I'll just disconnect the
cable so that it never even enters the house and then I'll just forget about
grounding it. Is there any reason why this would be unsafe or cause
Well, the Network Interface Box I have now is really old and in bad shape.
There's no NID or block or anything outside of house. The line comes
straight in. (I'll spare you the details, but let me just say that I'll be
calling Telco as soon as I get my electrical troubles in order.) Even so,
I'm glad you mentioned it. I can leave the top of the ground rod exposed
and that way Telco can have the option to run a conductor straight to it,
rather than using the split-bolt method. At this point I have no idea what
they will do or if they will even install an outside NID. One way or the
other, the current telephone junction box needs replacing.
If I'm following your line of thinking, then wouldn't it be slightly better
to run the TV Antenna ground straight to the grounding rod tip as opposed to
split-bolting it to the main ground (coming from the service panel and
heading towards the rod)?
Oh, an in case I don't hear from Thomas Horne, is bare 4 gauge copper
conductor appropriate for grounding the service panel to the grounding rod,
or must it be insulated with plastic? (I was just at Lowes and the
"x-electrician" there says I only need the bare wire)
Thanks. Sorry for being so caught up in the details. I really want to do
this right and do it safe, and I'm not getting the same answers from the
Thanks to both Toms (and everyone else) for all the clarifications. Words
are cheap, but I really do appreciate the help. I'm ready to let the
Electrician lead the way, but now I can make sure all is on the up and up.
Of course, knowing me, there's one last detail. Power comes into my house
to a main breaker box, then goes out to a separate modern service panel.
The main breaker box is nothing more than a 100 amp breaker with no bus bars
or anything like that. (Sorry if that was obvious). Power goes through
this main breaker and over to a separate modern service panel. Likewise, a
4 gague copper ground conductor leaves this main breaker box and goes out to
the modern service panel.
Currently, the GEC leaves from the main breaker box and goes out through the
basement wall to earth ground.
If I understand correctly, from what I've learned here, the new setup should
have the GEC going from the ground bar of the modern service panel out
through the wall to the grounding rod, instead of the GEC coming from the
initial main breaker box. Is that correct?
(If the correct method is to run the GEC from the initial breaker box, then
does that mean the water pipe ground conductor should also be grounded to
this same box as opposed to using the modern service panel's ground bus
And with that, I'll let this long thread putter out. Thanks for sticking
with me and my poor newserver access. lol.
Just to be clear, there is a small 4 inch bar that accepts the incoming
ground and allows for the copper conductor to leave the box to go to the
earth ground and another to go to the modern service panel. I just meant
there's no modern style bus bar and no room for additional circuits or
anything like that.
I guess I could be convinced to install 2 rods. I'm doing the work to
install the first.
If I plant the ground rods just outside the wall of my service panel, I'd
have to dig 20 yards over and eight feet down to bring the #4 to the water
pipe. If I run #4 from the ground bar to the water pipe from inside the
house and then do two ground rods, won't that be enough?
If I bond the hot water pipe, I'm guessing I would do it the same way as the
cold (from the inside).
What do you mean by "jumping around" the water meter?
Don't get me wrong. I trust the advice here or I wouldn't be here. But
here's the bottom line for me. Whatever electrician the previous home owner
hired didn't do the job right, the electrician I hired to inspect the home
before I bought it didn't see the problems, and the electrician I'm
currently paying to fix things now is contradicting the advice I'm getting
here. I guess I could go to the yellow pages again, but at this point I if
I don't know what "right" is, I don't think I'll ever have peace of mind
over what work is finally done.
I had the gas guy out ther other day. Although the pipes I see are metal,
he said the lines underground were plastic, but I'll make the call to make
I'll look into that, but it seems like overkill at this point.
I have a $35 surge protector I use for electrical and telephone.
Power enters the house in the form of two hot conductors going to the single
100A breaker box
and then exit the box, going to the modern service panel. The neutral
conductor coming into the house
goes to a short metal "bar" which is bonded to the box itself, and then it
also leaves the box and goes
to the neutral bar of the modern service panel. From inside the 100A
breaker box, from that same short metal "bar" there are also two 4 gague
bare copper conductors that leave the box. Currenly, one leaves the box and
goes through the basement wall and out to earth ground. The other copper
conductor leaves the box and goes to the ground bus bar of the modern
Thanks keeping me straight on the details.
On Sat, 12 Jul 2003 13:59:42 GMT, "volts500"
Pardon me for thread jumping... I need to do this too.
What's the theory behind getting outside the drip line ? Just
avoiding the extra moisture on the connections ? I'd think it
would actually help the conductivity to the rod.
Also, are you strong on the "two rod" approach even with the
a water pipe serving as one leg already ?
Again, theory question... why does the _hot_ water pipe meed to be
part of the ground system ? I'm not questioning doing it, sounds
easy enough to jumper, I'm just wondering why it's needed.
Is there a particular model you recommend ? I have looked over sites
like Intermatic (http://www.intermatic.com/?action=div&did=6 ) but they
have TVSS units, surge arrestor units, etc. Even if I concentrate on
the surge arrestors units, they have 120/240, 240/120,
two pole, three pole, etc. I do plan to have an electrician do the
work with this part but I have a feeling he might not know much
more about the _units_ themselves and how the manufacturers compare
than I do.
I have only a service panel with a main breaker... do I want a
"service entrance" unit or a "panel board" unit" ?
OK, I missed the point. You're saying "get it into the moist ground
that is hit by the rain". I thought you were saying "get it away
from the drip line 'cause it will get wet.".
I may have some issues with the depth. You hit hardpan in my yard at
6 to 8 feet deep. I don't think a copper rod will got through it,
no matter what. The stuff is like concrete, I couldn't get through
it with a steel truck bar.
How deep does the ring have to be ? Does it really need to be a
circle ? Or could I run 20 feet along side the house in a ditch ?
Good point. Since the water heater is right next to the HVAC, I'll
run a wire to the ductwork too. Can't hurt - if it does, something
OK, sounds good. I may have to replace the meter box to do that as it
is barely big enough for the meter itself. It's a bit rusty and I was
thinking of doing it anyway, so maybe I'll wrap it all together into
one project for my electrician.
Sorry, living on an overgrown sandbar, sometimes I forget how hard it is to
drive ground rods in some other parts of the country. The NEC permits a
ground rod to be driven at a 45 degree angle (no less), if that helps.
2 feet deep, doesn't need to be a circle, but make it as long as you can
past the required 20 feet.....use a #2 copper.......keep the trench beyond
the roof drip line, where the soil will stay wet(er).
Thanks. One of those options will do it for me. I was shocked the
first time I ran into hardpan. I thought someone had poured a giant
concrete layer under my yard. I'm told it can be 2 to 15 feet thick -
although I've never gotten more that two inches into it so I can't
One last question: Why is the wire that feeds the ground rod/ring have
to be bare ? Are they afraid that a lightning surge will melt the
insulation and reduce the conduction when it gets around the strands ?
I'd definitely see the advantage for the ground ring. I was thinking
about the "feeder" wire from the box running down the side of the
house. It just seems like insulated copper would keep a better
(clean) connection between the strands of the stranded as opposed
to bare copper exposed to the weather. Maybe bare in PVC is the
way to go.
One more "last question": If I (re)run the ground wire to the water
pipe is it the usual "staple every three feet" requirement ? Also,
the existing ground wire runs in a "channel" above the foundation
and below the joists where there are another half dozen pieces of
romex in close proximity. Is this an issue or is it OK
to run parallel to these ?
Wow, thanks for the generously long reply.
Well, the truth is I didn't discover that I need a new grounding rod, I
discovered, upon tracing the GEC, that the conductor was severed due to
corrosion. Right now the only ground I have is #4 going from the ground bar
(in the modern service panel) to the cold water pipe inside the house. I'm
not doing anything without the electrician, and nothing without shutting
down the main disconnect first.
Then, that's what I'll do. (or hire someone to do)
Right, understanding that a the point of the first main disconnect box the
"netural" busbar is the only busbar there is, and it is at this same bar
that the ground conductors originate as well.
>Usually once the all the connections are made to the ground rods they are
Okay, I still need to make that call.
To restate, the water heater, incoming gas line, and incoming power line
(and the service panels) are all in one corner of the basement so those are
short and easy access. However, the water line actually enters the home
about 30 feet away, and there's one right angle turn to get there, although
I could probably make the bend much more gradual. Because the water meter
is located less than three feet from the point at which the the water pipe
enters the home, if I install ground clamps on both sides of the water
meter, I'm assuming I won't need to worry about another clamp "within 5
feet of where the water pipe enters the house". Knowing it's a 4 foot run
to the water heater and another 30 foot run to the water meter, do you still
recommend using an UNBROKEN wire?
"it" meaning the water meter.. in case it ever needs replacing.. got it.
Okay, this sounds like a good way to do it. Because using a conductor to
join the water pipe and the grounding rods OUTDOORS would be very difficult,
is grounding the water pipe from the inside (as you describe) really an
adequate substitute? Also, because the ground rods will be located at one
part of front yard while the water pipes enter the home about 20 yards away,
will this be a problem having "two separate ground" locations, so to speak?
I'm just going to have to get some images up for you to see. I've tried to
find online diagrams or descriptions of how the panelboard should looked
properly wired, but I can't find any. Let me try one more time to describe
it. Incoming power to my house has three stranded conductors contained in
one cable. The two hot conductors are insulated and the third is bare
metal. These conductors are several times the size of a 4 gague wire,
including the bare one. Inside the main disconnect box, the two hot
conductors go to the solitary 100A Breaker. The bare metal conductor goes
to what I guess we have been calling the neutral "busbar". This little
busbar is grounded to the box itself, and from this busbar a relatively
smaller #4 wire originates and, acting as GEC, goes out to earth ground. A
second #4 wire also originates from this bus bar and goes out to the
grounding bus bar of the panelboard (which I have been calling the modern
service panel). Leaving from the main disconnect box is a cable exactly
like the one that comes into the main disconnect box. The two hots go to
the 100A breaker IN the panelbox. The neutral goes to neutral bus bar of
the panelboard. There is no green screw that I can see, but it seems clear
that a metal bar grounds one bus to the box itself.
Although the electrician already said it was okay, I'll have him look at it
again to be certain. I really am going to let him mess with it rather than
doing it myself.
I may not understand the term, but there really isn't any kind of cable
ground block outside the house. Cable runs down the house to a splitter,
then enters the house in two places. I guess I could install some kind of
"antenna discharge unit" and run a ground from there. But you're saying I
should run the #10 outside the house all the way to one of the grounding
rods? It's literally on the opposite side of the house from where the rods
will be. It would be a very long horizontal run at best IF I dug under my
sidewalk and/or porch. If I don't go under the concrete, then I'd have to
go along side the house and over the front door and past a few windows. My
wife would kill me. Would it be unsafe to run the #10 ground through the
INSIDE of the house? (That's the way it is now)
Ok, will do.
Tell me, what DO you get out of helping out guys like me? Is is just good
samaritanism? I'm always amazed at how generous some people are with their
knowledge and time. I really do appreciate it.
I will Volts500. Thanks for your genuine concern.
And I could use the Square D instead of the TWO rods, and you think that
would be better? If so, that's what I'll do.
I'll check it out. I can't thank you enough.
I uploaded two images. The top image show the first box power comes into,
or the service disconnect. The bottom picture is the modern service panel
which branches off from the service disconnect.
Does it look like this busbar will be able to support 4 outgoing conductors?
1. #4 ground going to grounding rod(s)
2. #4 ground going to water pipe
3. Big gague mesh going to service panel neutral bus bar
4. #4 ground going to service panel ground bus bar
If I can't put more than one conductor on each bolt, then I'm guessing I'll
have to upgrade. Will I need to change the whole box or can I just upgrade
Modern Service Panel:
Some connections have actually be corrected since this picture was taken,
but please comment as-is and I'll know what to change. You'll notice that
it's upside down. This is how it was installed. The #4 ground coming from
the service disconnect enters the panel and attaches to the LEFT bus bar.
It attaches to the bus bar in the same as you would install a wire for a new
circuit. Is it correct to assume this wire should have been installed to
the heavier bolt to the lower left of the bar?
Please identify at which point the ground bus grounds to the box.
I've got a new electrician coming over in a day or two. Hopefully, this
will be my last post.... thanks for your patience.
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