Volts500,
Wow, thanks for the generously long reply.
Another thing......it's _not_ a good idea to be working on the electric
grounding system while the system is energized......you can be electrocuted
if the right conditions prevail (such as a low ampere ground-fault that
hasn't been cleared). Best to do as much preparation as possible (like
drilling holes, running ground wire, driving ground rods, etc.), then shut
down the main disconnect before
removing the existing grounding system and fully install the new system
before re-energizing.......plus it can get hazardous when installing bare
conductors in energized panels.
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.
The first thing that I would do is determine that the TV antenna is as far
away as possible from any overhead electric lines and the electric service
drop. I would then drive an 8 or 10 foot ground rod directly under the
antenna mast
(assuming roof mount), at least 18" away from the house...enough to get
outside the roof drip line.
Then, that's what I'll do. (or hire someone to do)
I would then drive another 8' ground rod (again, outside the roof drip
line)
close to the electric service and at least 6' (or more) from the TV antenna
ground rod.
I would then run a #4 bare stranded copper wire from the neutral busbar in
the first (main) disconnect box to the ground rod installed close to the
electric service.
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.
Pull enough extra wire to get to the antenna ground rod
without splice, then slip an acorn grounding connector over the wire and
attach it to the first ground rod.......then use another acorn to attach
the
#4 to the antenna ground rod (leave enough room at the top of the ground
rod
for another acorn.
Usually once the all the connections are made to the ground rods they are
driven below ground. If you want the connections to be accessible, you can
cut an 8 or 10 inch long piece of 4 inch PVC (gray, sunlight resistant)
conduit and install it around the ground rod at finished grade level.
Exposed connections to ground rods are required to be protected or driven
below finished grade.
I would then attach an antenna discharge unit (on a non-metallic surface)
to
the side of the house about a foot or so above grade. After attaching a
ground clamp to the TV mast, I would run a #8 or #10 copper wire from the
mast ground clamp, through the lug on the antenna discharge unit, unbroken,
and on to the antenna ground rod, using another acorn. The antenna
lead-ins
are then attached to the antenna discharge unit and brought into the house.
OK, antenna is done. On to interior gas line. The NEC requires that an
_interior_ gas line be connected to the grounding electrode system. After
calling
the gas co. to be sure it's OK with _them_, one way to accomplish that goal
would be to be to install a ground clamp on the gas line closest to the
main
disconnect and run a #4 bare to the neutral busbar in the main disconnect.
Okay, I still need to make that call.
Ok, gas is done. On to the water ground. I don't know where your water
heater is located or if you have a water meter inside the house, but the
idea is the same as for the TV antenna run.......install a ground clamp on
the metal hot and cold water pipes near the water heater.....then install
ground clamps on both sides of the water meter. Then (if possible) run a
#4
bare from the neutral busbar in the main diconnect, UNBROKEN, through the
ground clamps on the water heater, through the ground clamps on the water
meter,
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?
leaving enough of a loop at the water meter so that it can be
replaced without disrupting the continuity ot the GEC,
"it" meaning the water meter.. in case it ever needs replacing.. got it.
and on to a point
within 5 feet of where the metal underground water pipe enters the house.
It doesn't have to be done exactly like that, but that's the way I would do
it, if possible. At the very least an unbroken #4 must be ran from the
neutral busbar to within 5 feet of where the water pipe enters the
house.......then jumper the water meter and hot water with short pieces if
you want.
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?
The neutral and the equipment grounding conductors are bonded to each other
and the service equipment enclosure _at_ the main disconnect _only_. Your
description of the feeder from the main disconnect to the panelboard
sounded
kind of hokey.......the cable running to the panelboard should be 4 wire
(in
the _same_ cable or conduit) and the panelboard neutral busbar should be
isolated from ground (look to see if a green screw goes through the
panelboard neutral busbar and into the back of the panel, if so, remove it.
The green screw is called the "main bonding jumper," but it also can be a
wire or strap in-leu of the green screw.)
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.
OK, water ground done. On to cable TV. While you say that you won't be
using cable, now is the time to get a decent ground connection to
it.........if cable is installed later and not grounded properly, the TV,
VCR and/or cable modem, and possibly the computer will be subject to
damage.
From the outside cable TV ground block, an insulated #10 can be split
bolted to any of
the above mentioned ground wires.
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)
Now for the phone. The telephone primary protector should be installed
outside the house by the tele co. and attached to the bare #4 that's coming
outside to catch the ground rod......or to the ground rod......whatever
floats your boat. This connection is best made by the tele co. people
though, if/when they come out to get the demark box right.
Ok, will do.
The ground conductors connecting the phone and cable ground blocks to the
grounding electrode system are usually a insulated
wire from the ground block to where they are connected to the grounding
electrode system.
Like I said, that's how I would do it. Without seeing it, that's the best
I can do for you. Actual installation may differ somewhat, but that's the
general idea. One thing is for sure, as slow as I type, I could have done
had the job done for you in the same amount of time that it has took me to
type this post.
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.
Please get it inspected by a _real_ electrical inspector.
I will Volts500. Thanks for your genuine concern.
If your neutral busbar in the main disconnect can't acommodate all the
wires, you'll have to buy one that will.
Also, a Square D lightning protector at Home Depot only costs about
$35..........takes about 5 minutes to install.
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.
If you want an authoritative book on the subject of grounding here's one
recommended by the IAEI (International Association of Electrical
Inspectors.
Soares Book on Grounding, 8E http://www.iaei.org/products_books.htm
I'll check it out. I can't thank you enough.
