Bond all grounds together?

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I understand that the NEC requires that all grounds (e.g., lightning protection grounds and grounds for radio transmitting equipment) must be bonded to each other and to the utility company's ground. The books I have read say this is accomplished by connecting everything to the ground "at the service entrance panel." But how is this to be accomplished? By clamping the ground conductors to the conduit (after cleaning it down to bare metal) that comes out of the ground and up to the meter on the wall of the building? By bringing the ground conductors through the wall of the building and into the panel and there connecting them to the existing ground bus? Or . . . ?
MB
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I suggest you locate a Soars book on grounding. Probably the best explanation to the industry. I also suggest that you start talking to the local folks that do this sort of thing. Check around for the local Independent Electrical Inspectors Association chapter or a Power Quality Association in you area. Both are great people and are willing to help. I belong to both, they have been a great source of increasing my intelligence.
Most folks take all of the grounds and tie the ground leads together on the main grounding bus at the service entrance. Which can prove to be a problem depending on the size of the ground bus. I have actually had to modify the ground bus to allow for the size of wires that were needed.
I submit to you that you DO NOT want to tie an lightning protection to your electrical service. Lightning protection is a sacrificial system. It dies for the life of the building. All of the lightning systems (UL96A) I have installed were grounded separately from the electrical service by at least 10 feet. I did a hospital that wanted the connections as you describe. When I checked with the gas company they FREAKED. Letters came fast and furious. No lightning protection connection to the gas line or no gas period. The last computer building I did had 2 ground rings one for electrical stuff and one for the lightning protection system, separated by 20 feet of earth. The amount of energy that a single lightning bolt CAN deliver is sometimes close to infinity for a fraction of a second.
I am a wizard, what I deal with is invisible. If you try to touch it; it will kill you.
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terminals shall be bonded to the building or structure grounding electrode system"
Nate
-- http://www.NateTechnologies.net:8000
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Nate, you are absolutely correct about Article 250.106. Further, Section 3-14 of NFPA Standard 780, "Standard for the Installation of Lightning Protection Systems", states: "All grounding media in or on a structure shall be interconnected to provide a common ground potential. This shall include lightning protection, electric service, telephone and antenna system grounds, as well as underground metallic piping systems." This section specifically states that "Interconnection to a gas line shall be made in the customer's side of the meter.", which may have been the source of excitement when the gas utility inspected SQLit's installation.
Mark
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Minnie Bannister wrote:

You can ground to the meter enclosure, the service panel, the service raceway (assuming it's metal), or anyplace you can get to the grounding electrode conductor. I like using a split-bolt connector on the big bare copper ground conductor where it comes out of the service panel.
In your case, I think I would use a ground clamp on the service raceway outside the house by the meter. Or attach a big terminal lug on the meter enclosure itself with a big (and short) sheet metal screw and lock washer.
Best regards, Bob
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Minnie-
Are you asking as a matter of general curiosity, or are you attempting to correct what you believe to be an existing grounding problem?
Mark
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I am asking for practical instruction how to ground my antenna tower (when I erect it), etc. in accordance with the NEC.
MB
On 02/15/04 06:04 pm Mark put fingers to keyboard and launched the following message into cyberspace:

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Ground rods are normally bonded by interconnecting them with #6 copper wire. This may be one case where using larger wire is not desireable -- use the #6 between the electrical system ground and the lightning type grounds, but perhaps use larger wires between any other electrodes in the respective systems. If the lightning system is permitted to use wires smaler than #6, then I'd use the minimum allowed wire between the two systems and consider a supplemental rod in the lightning system and use a larger wire like #4 or #2 to it.
-- Mark Kent, WA
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Now that most of the snow has melted here in W. Michigan (although more is forecast for tonight) and I have been able to get a better look at the existing grounding arrangements, I have noticed that a heavy stranded copper wire comes out of the ground alongside the conduit that goes to the electricity meter; it then disappears between the slab and the siding, so I assume that this is the ground connection to the ground bus in the panel -- correct? If so, do I have to bring my separate ground connection (from a radio installation, including a future antenna tower) up into the panel, or can I simply bond it to that existing accessible ground conductior outside the house?
The gas meter and telephone network interface are on the opposite end wall of the house. The first thing I noticed is that an insulated wire that comes out of the ground alongside the gas pipe is simply twisted around it, with the bared end just "flapping in the breeze"; there are no marks on the pipe to suggest that the wire was ever clamped to it. Should I install a clamp myself, or should I call the gas company? (The telephone interface box is just a few feet away from the gas meter, but the wire that disappears into the ground from it has a different color insualtion from the one wrapped around the gas pipe, so I don't think the floating wire is supposed to be the ground for the telephone.)
But one other question comes to mind: can I really believe/assume that these existing grounds are all connected together already? Is there really a conductor running the 60ft or more from the gas meter and telephone interface at one end of the house to the electricity meter at the other end? How can I be sure?
MB
I wrote:

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Minnie Bannister wrote:

Measure the AC voltage between them. Different grounds differ by some part of a volt (AC). That's a one-way test, to tell they're definitely not connected if you see voltage.
I get a half volt (AC) just between a couple of ground stakes driven into the yard, anyway. If lightning hit nearby, it would be thousands, which is why you don't want two unbonded grounds inside the house together.
Set the meter on AC not DC. The voltage you see is from power grid grounds reconciling themselves in the earth so it's AC too.
--
Ron Hardin
snipped-for-privacy@mindspring.com
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Minnie Bannister wrote:

You should be able to attach to any accessable point on the grounding electrode system. That big copper wire sounds like a winner. I'd clamp to it with a copper split-bolt connector.
Bob
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(Minnie Bannister) writes:
| The gas meter and telephone network interface are on the opposite end | wall of the house. The first thing I noticed is that an insulated wire | that comes out of the ground alongside the gas pipe is simply twisted | around it, with the bared end just "flapping in the breeze"; there are | no marks on the pipe to suggest that the wire was ever clamped to it.
That sounds like a tracer wire, not a ground.
| Should I install a clamp myself, or should I call the gas company?
I wouldn't make any changes without asking the gas supplier.
| But one other question comes to mind: can I really believe/assume that | these existing grounds are all connected together already?
I wouldn't assume that they are connected. The professionals from the telephone companies (and from the cable companies) sometimes skimp in this area, and there is rarely an inspection to catch them.
                Dan Lanciani                 ddl@danlan.*com
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Basically, yes, in this case, you should connect to the grounding system outside the house. However if you have an overhead electric service you should locate the antenna/tower as far away from it as you can. For a roof mounted antenna the ground wire should go from the antenna (line of sight) straight down to an antenna discharge unit then straight into a ground rod driven far enough away from the house so that it is outside the roof drip line. That ground rod should then be bonded to the main electric service grounding electrode system using preferably, a #4 bare copper conductor.
Also, if you have an underground metal water supply line, it's very important that you have have an unbroken (preferably #4) bare copper wire connected from within 5 feet of where the supply line comes into the house routed to the main electric service. Jumper across the water meter if applicable, and jumper from the hot to cold at the water heater, if metal pipes. Any sections of metal pipe that may have been replaced with plastic pipe should be jumpered also. Use UL listed/approved ground clamps/connectors, preferably bronze.

That doesn't sound good. A grounding connection should _never_ be made to an _underground_ gas line. However, any _interior_ metal gas line should be bonded to the main electric service grounding system. Local codes may vary.

Completely remove any kind of grounding connections to the outside and/or underground gas lines. To be safe you should shut down your main electric service before working with the grounding system.

That doesn't sound good either. There's a possibility that the telephone interface box is grounded to the underground gas line. You'll want to carefully dig that wire out until you find where is goes. If you are lucky that phone ground wire goes to a ground rod that is installed as far away from the gas line as practical, then that ground rod should be connected to the main electric service ground on the other side of the house, again, preferably with a bare #4 conductor.

I seriously doubt it, but there should be.

Carefully dig until you see where the wire is connected. See above.

The wire coming out of the meter and into the ground is probably the best place to connect in your case. Most times the grounding connections are made inside the main service panel on the neutral busbar and the neutral busbar is then bonded to the panel enclosure.
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On 02/23/04 04:01 pm volts500 put fingers to keyboard and launched the following message into cyberspace:
<snip>

No sign of any wire between the water pipe at any point and the electrical system ground, and no sign of connection between hot and cold pipes. Yet I did measure a low resistance (< 1 Ohm) between the pipes on either side of the water meter (despite the Teflon-taped joints), between the hot and cold water pipes (after all, they are both conencted to the water heater), and between the water pipes and the case of the electric panel.

No sign of a connection between the gas line and the electrical grounding system either. But the gas line is connected to the water heater, which is connected to the water line, which appears to have a low-resistance connection (somehow -- see above) to the electrical system ground.
>>(The

I found where the wire from the telephone network interface box goes: it is connected to a cold water pipe inside the house, which is ultimately conected to the incoming water supply -- all copper piping, except for the sprinkler system.
How recent is the requirement that all grounds must be bonded together? This house is 30 yrs old.
MB
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Years ago, when metal water pipes were used, it was permissible to use the interior metal cold water pipe as part of the grounding electrode conductor (not any more). Look for a cold water pipe that is close to the electric panel, as you may find the connection there that goes from the water pipe to the panel. One should not depend upon the pipe connections at the water heater for bonding purposes, use jumpers.
You should try to determine if your underground water supply pipe is metal or plastic. If it's metal, it needs to be connected to the main electric service, no exceptions. It may be plastic since you seem to have a ground wire that comes out of the meter, to a ground rod, then to the panel. If the water supply line is plastic, you definitely need to bond the interior metal water pipes to the electric service.

I think Dan clarified that that wire may be a tracer wire for locating purposes, and of course,the gas supply line would be plastic then.

That would be a good place to bond all three together. If your underground water supply line is plastic, you could then run a ground wire from the cold water pipe nearest the panel, to the panel, which would then bond the hot, cold, and inside gas line to the electric service.

The wire from the telephone interface should be less than 20 ft. What you describe was permitted 30 years ago and would be grandfathered in. Since plastic pipe became popular, the connection is now required to be connected to the underground metal water pipe within 5 ft. of where the water pipe enters the building. Or connect it to the (GEC) Grounding Electrode Conductor (the one coming out of the electric meter.) If the ground wire off the telephone interface were longer than 20 ft. (on a new install) then you'd have to drive a ground rod at the interface and bond that ground rod to the GEC. You should be OK the way it is now since yourinterior metal water lines are intact.
If you have cable TV, it needs to be bonded to the electric grounding system also.

It's not a recent requirement, can't put a date on it though.

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Earthing for two separate reasons. First for human safety which is what the National Electrical Code (NEC) addresses. All safety grounds long ago have to be bonded together. In days past, the typically was to city water pipe where it entered earth or, if using well water, to a dedicated earth ground rod. In the past decade, earthing via a water pipe is not acceptable no matter what that water pipe currently is - copper or plastic.
Code since 1990 demands a dedicated single point ground at the service entrance which means where AC electric enters building. Telephone, CATV, satellite dish and even exterior TV antenna should make a connection to this ground (either by hardwire or via a protector). Code demands services such as phone make a less than 20 foot connection.
Ground wires to pipes are for human safety - only to remove electricity from those pipes. IOW wire once connected to city water as an earth ground is now only to remove any electricity that might leak into those pipes. Also required would be a connection from hot water to cold water pipes at water heater if pipes are metal; so that heater does not become part of the grounding circuit. Water meter must also be bypassed so that when water meter is replaced, then cold water pipes remain connected to safety ground (meter man is not electrocuted when changing meter).
Any connection to a pipe for grounding or earthing (ie a cable connected to exterior water faucet) is not legal. Again connections made to pipes only to remove electricity.
Ground to gas pipe is really a domain of the local gas company. Some want gas line bonded to AC electric so that electricity is removed from gas pipe - so that gas pipe will not be used as an electrical path to earth. In one location, neutral wire on transformer failed. AC electric then used gas line as a path back to transformer via earth. This unacceptable ground path eventually caused gaskets on gas meter to break down; house exploded. But again, that safety ground to gas pipe is according to local gas authorities.
Exterior gas line has a wire that is not an earthing wire. All pipes have a wire so that radio signals can be transmitted through pipe. This is how underground utility pipes and wires are located - radio waves. That wire on incoming gas line is how the locator service puts a radio wave on that plastic gas pipe. Wire is not for earthing.
A meter typically cannot report a good ground; meter can only report a defective ground. A ground that measures good may simply vaporize - is too small - when it must conduct larger currents due to an electric power fault. Meter would not detect an insufficient ground. No replacement for visual inspection. Furthermore, connections must be intended by the designer to conduct electricity. A water heater was not typically intended to connect hot water pipe to cold water pipe. No matter what meter says, those two pipes still must be bonded at that water heater (if metallic pipes).
volts500 wrote a good summary of bonding for human safety: alt.home.repair entitled "Grounding Rod Info" on 12 July 2003: http://tinyurl.com/hkjq
That covers safety grounds as required by NEC. Now second reason is to enhance earthing for transistor protection. Those safety grounds were defined by wire resistance. Transient protection is about wire impedance. That means connections to that single point ground must be short, direct, and independent. No splices, no sharp bends, less than 10 foot connection from incoming utility to that single point earth ground, and not inside metallic conduits or pipes. Phone line connects directly to earth ground rod - not to AC power earthing wire. IOW every earth ground wire must meet at same single point location and should route separated from other non-earthing wires. (non-earthing wire can suffer induced surges if bundled with an earthing wire.) This technical note demonstrates principles of earthing a tower and building: http://www.erico.com/public/library/fep/technotes/tncr002.pdf
Building and tower are handled as if separate structures. Each has it own single point earth ground. Any wire entering each structure first connects to single point ground either by direct connection or via components even sold by erico.com - and others. Single point earthing for both structures is interconnected by buried wire to enhance both earthings and minimize potential differences.
One technique is to dig a shallow hole before driving earthing rods. Buried wire connects each ground rod. A 4 or 6 inch plastic pipe placed in hole and backfilled so that plastic cap can be removed to inspect wire bond to ground rod.
Size of buried interconnecting bare copper wire, depth of that wire, and spacing between multiple rods are defined by NEC guidelines. However, effective earthing materials (ie ground rods) must be deep enough into earth where earthing will not freeze. Frozen earth is not conductive - not a good earth ground.
Minnie Bannister wrote:

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On 02/24/04 01:53 am w_tom put fingers to keyboard and launched the following message into cyberspace:

I am not sure what water pipe material is used outside the house. The municpality was in the process of repairing or replacing the pipe from the street to the house when we were looking at the house before buying it. By the time we took possession everything was filled in again. There is such a short length of pipe coming through the basement wall before it connects to a brass or bronze fitting that I can't tell for sure, but I think it's probably iron.

The telephone connection comes into the house at the opposite end from the electric service entrance -- 60ft or more away -- so no way to comply with the 20ft rule. The cable TV service (now used for Internet only) enters at the back of the house, perhaps about 45ft from the electric service entrance; there is a ground wire from the cable company's box, but where it goes I have no idea. The satellite dish, installed "professionally" about 3 months ago, is about the same distance from the electric service entrance and with no sign of a ground wire at all: the coax. cables come straight down from the dish and through the wall of the house at a level just above the suspended ceiling of the basement and, as far as I can tell, go straight to the satellite box; if they do pass through a grounding block, I have no idea to what that grounding block could be grounded.

The water meter is connected to two "arms" of a single brass or bronze fitting in the line just after it enters the house, so there is a permanent continuous electrical path even if the meter is removed.
But now if I want to ground the water pipe to the electrical supply ground, can I run a wire to the ground bus in the panel located a few feet away (in the laundry), or do I have to find a way of connecting that wire to the ground at the service entrance panel (which has only the main breaker and a breaker for the garage circuits) about 30ft away on the garage wall? This would mean bringing the wire from the front of the house (where the water line enters through the basement wall), through the house (above the suspended ceiling of the basement), out through the back wall, and around to the end of the garage where the electrical service enters.

Agreed.
The water heater was replaced two years ago, according to the "seller's declaration," but I have no idea whether it was done "professionally" and in accordance with relevant codes. It will be easy to bond the two pipes together; I assume that #4 is OK? Stranded or solid, or doesn't it matter?

A lot of that I know in principle, but how to apply the principles to a specific situation is not always obvious. E.g., when all these things that are supposed to be bonded together are so far apart.

I like that idea, which I don't recall reading in any of the radio-related publications.

One of the locals merely cut a groove in his yard with a power saw (sacrificing a blade in the process, no doubt) and laid a ground wire in that (but in conjuction with deep-driven rods, I think). Perhaps not such a great idea?
MB
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Described is an earthing nightmare if intent is to also protect household electronics. Does not matter, for example, if CATV is only used for internet. Cable can still make a destructive connection to other appliances. Things like linoleum tile are electrical conductors where discussing transients - meaning a house is full of other conductive circuits. Once a destructive transient is inside the building, then it will find many destructive paths to earth ground. Best to earth is to a single point ground
Provided is one alternative to your bonding problem. Looping the building (ie halo ground) makes earth beneath equipotential. Connecting earthing for telephone, cable, and AC electric to this loop helps make all part of a common bond both for human safety and transistor safety: http://www.cinergy.com/surge/ttip08.htm
It does not matter whether water pipe is currently metal or plastic. The concept is siple. Water pipe, anyplace in the earth, may at any time become plastic. Therefore water pipe, today, is no longer acceptable as an earth ground. Code says upgrade must use a dedicated earthing system. You don't care whether a metal pipe section was replaced with plastic. Assume it is or will be replaced by plastic.
They should have routed satellite dish wire to service entrance to be earthed, less than 10 feet to the AC electric earth ground. Only then does cable rise back up to enter building. Recently, many cable companies are now just starting to do this. Dish satellite installers cannot be bothered; too much work. Apparently they get paid by the job; meeting code is irrelevant. No help for you. But when that cable enters building, it must, at minimum, connected right there to an earth ground rod. Again, to bond that ground rod to AC electric, see above pictures and concept from cinergy.com . A halo ground solves many problems.
I thought you said the existing electric panel was bonded to city water pipe? Why now are you asking how to bond to that water pipe? Now I am confused based upon that last question about grounding to pipe. Why ground to a pipe that was already the household earth ground?
Minnie Bannister wrote:

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On 02/25/04 01:25 am w_tom put fingers to keyboard and launched the following message into cyberspace:

What are my chances of "leaning on" the installers and having them rectify the situation? Can they legally be compelled to come back and do it right?
Or what about running the cables through a grounding block at the satellite box, then running the grounding wire back out through the wall to a ground rod that will be connected to this halo ground (yet to be installed)? Not grest, perhaps, but better than nothing, I guess. (And what if the "halo ground" does not completely surround the building? How would I get it across/under the driveway, for example?)

No. I am sure I said originally that there is no sign of a wire between the water pipe and the electrical ground. I did say that I had measured a low resistance (< 1 Ohm) between water pipe and electrical ground, but I have no idea how that comes about; perhaps it is simply the resistance of the wet (at the moment) earth with which they are both in contact?
MB
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On 02/25/04 08:49 am Minnie Bannister put fingers to keyboard and launched the following message into cyberspace:

Or, now that I think about it further, it seems it would be much better to run my own ground wire from the dish to a ground rod connected to the halo ground.
And when I looked again at the diagram on the Cinergy Website, I saw that it does depict a ground that goes only partway round the building. I was confusing it with another diagram showing the ground wire going all the way around the building.
MB
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