Driving a seperate ground rod

I think the electricial service in my house is adaquate, but I suspect that my copper pipe is not. Would it be legal to drive a seperate ground rod to bond the copper pipe in my basement? We were on a well at one time but now we have county water. The piping from the county to the house is pvc.

The reason I suspect the copper pipes is that during an electricial storm I lost a modem once. It would power up but the phone line part would not function. The incoming phone line is bonded to the copper pipe in the basement.

I now have two computers that I think the mobo's are dead. There was a storm before I came home. The computers are plugged into a surge suppressor and a UPS. The power supplys in the computers are good, but I strongly suspect that the mobo's are toast. I am afraid they took a hit from the Cat 5 coming from the modem. The cable is also grounded with the same copper pipe.

The sad thing is that the UPS does have protection for the Cat 5 cable, but during some trouble shooting I had done in the past the Cat

5 was not re-hooked to the UPS.
Reply to
Terry
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It's not only legal, its required. Install the rod and connect the cable to the neutral -ground bar in your main service panel. Any copper internal piping should also be bonded to the grounding system

Reply to
RBM

Thanks.

Would it be legal to connect it to the neutral bar in a sub panel in the basement?

Reply to
Terry

No, the neutral bus should only be bonded to the ground in the Meter/Main Panel, not the Sub-panels.

The thing they started doing here (Sonoma County California) is to run 20' of #6 Copper solid wire mixed and inter-twined in the rebar of the foundation. then bring it up into the meter panel.

Scott Thanks.

Reply to
Scott Townsend

No, it has to be the main panel

Reply to
RBM

When the water supply was changed to PVC you lost the system ground. I agree with RBM, you need at least 1 ground rod. Ground rods are not very good, but they are far better than what you have now - nothing.

Starting with the 2005 NEC, for most new buildings a ?concrete encased electrode? - one version of which is described by Scott - is required.

Excellent formation on surges and surge protection is in an IEEE guide at:

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a simpler NIST guide at:
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An important point is to have a "single point ground" - entrance protectors for CATV, phone, ... be connected with a *short* wire to the conductor to the earth electrode at the power panel. With a large surge there will always be a difference from the house ground to ?absolute? ground. The goal is for the power and CATV and phone 'grounds' to rise together. Sometimes entry points are distant but a phone, ... wire can be run from its entry point to a 2nd protector adjacent to the power service and phone wires distributed from there. Or use a multiport plug-in suppressor. (For an illustration of the hazard see the IEEE guide pdf page 40.)

The NIST guide cites US insurance information that indicates equipment most likely to be damaged by lightning is computers with modem connection and TV related equipment - presumably with CATV connection. All can be damaged by surge voltage between signal and power, and a single point ground removes much of the risk.

That is also why signal wires must go through plug-in suppressors, as you indicated. All interconnected equipment must be connected to the same plug-in suppressor, or external wires must go through the suppressor. A plug?in suppressor clamps the voltage on all wires (signal and power) to the common ground at the suppressor. Mulitport suppressors are described in both guides.

And the final protective device that can be used is a surge suppressor at the power service. They are also described in both guides.

-- bud--

Reply to
bud--

The MDP (main distribution panel) needs to be grounded with a ground rod to have 25 ohms resistance or less. In an updated system, subpanels cannot allow neutral and ground to terminate on the same bar or allow the neutral to bond to the panel, the neutral path and ground path are maintained separately. Here is a discussion:

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Reply to
DanG

does the old water line to the well still exist? excellent ground connect it to the new ground rods for maximum safety and protection

Reply to
hallerb

Does the code actually require that now?

This implies it still does not.

The old requirement was that if the first rod was over 25 ohms you had to put in a second rod. Testing resistance after that was not required even if/when it was still over 25 ohms. This is the source of the "drive two go home" stuff -- if you can't test, two rods will always, by definition, meet code.

sdb

Reply to
sylvan butler

Thanks for every one's comments. Boy those typos were bad. :)

Reply to
Terry

Your post implies earthing to eliminate surge damage. Earthing must answer to many masters. For example, it is required by code for numerous human safety reasons. Any fault must trip a circuit breaker. Transformer neutral failure will not cause excessive currents via gas meter and resulting explosion. Etc.

Earthing for transistor protection means earthing also must exceed post 1990 code requirements. Code only addresses human safety which is why water pipe earthing is no longer sufficient and does not meet post 1990 code requirements. For transistor protection, that same earthing also must exceed code requirements.

Code says breaker box (with main disconnect) must be earthed (some jurisdictions want this earthing in the meter panel). For transistor protection, that earth must also be less than 10 feet, no sharp wire bends, no splices, everything earthed to one electrode, etc. Code does not demand any of this. But to eliminate motherboard surge damage, these are some additional requirements for earthing.

Still that is not sufficient. For example AC electric service has three wires. If any one wire is not earthed, then modem damage can result. But how is AC electric delivered when all three wires are earthed? Neutral wire must be earthed directly. But other 'hot wires' must make that 'less than 10 foot' connection via a protector.

Notice what a protector does. It does not (and does not claim) to provide protection. The protector is simply a connecting device to earth ground. Nothing more. A protector without that earth ground many even earth surges destructively via adjacent appliances (Page 42 Figure 8 in

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A protector that makes that 'less than 10 foot' earthing connection means 1) surges will not enter a building to seek earth ground destructively via modem and motherboards, 2) protection inside all other household appliances is not overwhelmed, and 3) everything in the building human safety appliances (ie smoke detectors, GFCIs) also are protected.

Earth ground is the protection. Protection improves when a single point earth ground is even made better (ie 'less than 10 foot connection). Most important - every incoming wire in every cable must connect 'less than 10 feet' to that earth ground before entering the building. Your telco does that so their switching computer connected to overhead wires all over town is never damaged. The technique is that effective and that well proven. Again, the protector is only a connecting device to protection. Better protection means better earthing.

Did you know the telco installs a 'whole house' protector on you phone line? Why? Because that protector is so effective and costs massively less compared to a plug-in protector. But again, if a protector does not make a connection to earthing, then the enter protection system is compromised. - like a water pipe replaced in PVC.

Cable TV does not need a protector. Why? Protectors do not provide protection. Cable is protected by a $2 ground block and a wire to the earthing electrode. Protectors would only diminish that protection - but enrich some manufacturers. What defines quality of that protection system? Earth ground. Better earthing means less surge will enter a building to overwhelm protection already inside all household appliances.

Above is the technology. If you learn the technology, then Bud's people don't profit by selling protectors without earthing. Page 42 Figure 8: TV damaged by 8000 volts because an expensive plug-in protector was too far from earth ground (basically had no earthing), plug-in protector was too close to appliance, AND earthing system violated principles cited above.

How to identify the ineffective protector? It has no dedicated wire to make that 'less than 10 foot' earthing connection AND manufacturer avoids all discussion about earthing. Therein defines where that ground rod must be located and how everything connects to it.

Do you run the ground wire from breaker box, up over foundation, and down to earth ground rod? Yes to meet code. Not sufficient to protect computers. The ground wire over foundation would have too many sharp bends, be too long, and would be bundled with other non- earthing wires. Ground wire bundled with other wires may even induce surges on those other wires. That ground wire must pass through foundation and down to earthing electrode. Wire must be shorter, less bends, separated, etc.

Concepts that define where an earthing rod is located and how connections are made are in comp.sys.mac.comm on 4 Jul 2007 entitled "DSL speed" at

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What happens when a plug-in protector has no dedicated earthing wire

- cannot make that 'less than 10 foot' connection? Page 42 Figure 8 is one example: the surge finds another path to earth - 8000 volts destructively - via the adjacent TV. TV earthed a surge because it was not earthed where wire entered the building. No earth ground means no effective protection.

Reply to
w_tom

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It that a yes or no?

What I really want to know is if I am "required" to ground a copper piping system in my house for grounding for the CATV if the piping may be replaced with PVC?

If grounding is not "required" then I am going to ask the CATV to come out and bond their service to my electrical service mast.

Reply to
Terry

There is no requirement in the NEC to bond a piping system that does not extend at least 10 feet out into the ground. There are still many inspectors who might well say they would sure prefer seeing a ground clamp on the pipe. It is easier to just put one on.

CATV should share your MDP bonding, usually a ground rod (pretty normally two here - cheaper than having an engineer or test lab stamp to ensure 25 ohms or less)

Reply to
DanG

Thanks.

That is what I wanted to hear.

Reply to
Terry

I am trying to digest your message a little at a time. This seems to assume that the surge damage was in the supply lines. I don't think this is how I took a hit.

I believe the surge came "from" the CATV during the storm. The power supplies in the computers are good.

The damage was the modem, router, and motherboards.

Thanks for your time

Reply to
Terry

NEC says cable must be earthed. Why would a surge that seeks earth ground ignore that cable ground to enter your house and damage electronics - then continue on to another ground?

Every incoming utility must be connected to earth where wire enters the building. That is code required. Water pipe is no longer considered sufficient. Install a dedicated earthing electrode (from the NEC list in article 250.52). Water pipe is no longer sufficient for earthing. Post 1990 code now says any other earthing electrode must be installed. See article 250.52(D)(2) entitled "Supplemental Electrode Required". That electode can be located so that every earthing connection is 'less than 10 feet', etc.

Your posts imply thinking of surges like waves on a beach. Electicity does not work that way. Did a surge enter on cable, damage modem, then stop? Of course not. Where is the outgoing path from modem to earth. No outgoing path means no electricity entered on incoming path. First current must be flowing to earth. Long later is a modem damaged. If surge was incoming on cable, then where is the outgoing path? No current first flowing out to ground? Then no damage..

Damage on cable side of a modem can easily be incoming on AC mains - outgoing via that cable. Surge passes through other things while not damaging those others. Damage would be only at a weakest point. Why would a surge ignore cable earthing, damage a modem, then continue out of modem (how?) to earth ground? Earthed cable is typically an outgoing path. AC electric is most often the incoming path to damage cable side or phone side of modems.

How modems were so often damaged: Surge on black 'hot' wire is shunted to green safety ground wire. Now that surge connects directly to motherboard and modem - completely bypasses power supply. Through modem's off hook relay (destroying off hook relay's PNP transistor) and out to earth via 'telco installed' protector. Just another example of AC line surge that passes through everything but only damages something.

Repaired many modems by only replacing that one transistor. Modem worked fine for years even though other parts also conducted the surge. Only a weakest point was damaged.

Wires highest on utility poll are most often struck; most often a source of incoming surges. Next question - how did that surge seek earth ground? Best destructive paths to earth will only be via some appliances. Things you have assumed not conductive (power supply or linoleum floor tile) are possible conductors. Again, not like waves striking a beach. First current is flowing through sky, appliance, and earth simultaneously. Later something in the appliance fails. To protect, first identify all possible incoming paths - circuits that lightning would use to obtain earth ground via appliances because that wire was not properly earthed. Surge must be earthed before it can enter a building.

Critical earthing requirements include a 'less than 10 foot' connection and the electrode must be single point. Violate the requirements and lightning may seek other destructive paths to earth.

One utility demonstrates how to create a 'single point' when all utilities foolishly enter at mutliple locations. Single point ground is that buried interconnecting wire;

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Step back. Surge protection is not about the appliance. Protection must be viewed in terms of the entire properly. Effective protection 'systems' (so that protection already inside the appliance is not overwhelmed) is a complete building 'solution'.

Reply to
w_tom

All water pipes are bonded to breaker box so that any electricity (a fault) in those pipes is removed. Number one reason for bonding to water pipes is to remove dangerous currents. Number one reason is not earthing.

Also, nothing must connect to water pipes to dump electricity into those pipes (called grounding). Every electrical connection to household pipes is to remove electricity (ie trip a breaker) so that wet humans never conduct electricity.

Homes *bond* (not ground) water pipes. volts500 provides a nice summary of pipe bonding in the newsgroup alt.home.repair entitled "Grounding Rod Info" on 12 July 2003 at

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No longer acceptable is connecting cable to some water faucet. Cable ground as defined by NEC in article 800.33 must be made directly to NEC defined earthing electrodes in article 205.50. This is bonding and grounding for human safety. Then these requirements must be exceeded for transistor (modem) safety.

Reply to
w_tom

w_ has a religious belief (immune from challenge) that surge protection must use earthing. Thus in his view plug-in suppressors (which are not well earthed) can not possibly work. The IEEE guide explains plug-in suppressors work by CLAMPING the voltage on all wires (signal and power) to the common ground at the suppressor. Plug-in suppressors do not work primarily by earthing. The guide explains earthing occurs elsewhere. (Read the guide starting pdf page 40).

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The illustration in the IEEE guide has a surge coming in on a CATV drop. There are 2 TVs, one is on a plug-in suppressor. The plug-in suppressor protects TV1 connected to it.

Without the plug-in suppressor, the surge voltage at TV2 is 10,000V. With the suppressor at TV1 the voltage at TV2 is 8,000V. It is simply a

*lie* that the plug-in suppressor at TV1 in any way contributes to the damage at TV2.

The point of the illustration for the IEEE, and anyone who can think, is "to protect TV2, a second multiport protector located at TV2 is required."

w_ says suppressors must only be at the service panel. In this example a service panel suppressor would provide absolutely *NO* protection. The problem is the wire connecting the CATV entry block to the power service is too long (not a "single point ground"). The IEEE guide says in that case "the only effective way of protecting the equipment is to use a multiport protector."

Needs no protector? The IEEE guide notes that the voltage between cable center conductor and sheath is limited by the breakdown of F-connectors which is typically 2-4,000V. The guide notes that connected equipment can be damaged at those voltages. Plug-in suppressors are likely to clamp the voltage to a reasonable level.

To quote w_ "It is an old political trick. When facts cannot be challenged technically, then attack the messenger." My only association with surge protectors is I have some.

It seems w_ must discredit those that do not agree with his bizarre ideas.

The lie repeated.

And read the responses.

And the lie again.

And the required statement of religious belief in earthing.

The question is not earthing - everyone believes in it. The question is whether plug-in suppressors are effective. The both the IEEE and NIST guides says they are.

w_ has never found a link that says plug-in suppressors are NOT effective. He just twists sources, like the IEEE guide to say the opposite of what they actually say. Read the source.

And w_ has never explained why the only 2 examples of suppression, at the end if the IEEE guide, use plug-in suppressors.

--------------- If there is not 10 foot underground metal water service pipe (water pipe not used as a grounding electrode), the interior metal water pipe is still required to be bonded by 250.104-A.

-- bud--

Reply to
bud--

Dan That is incorrect. Any interior metal water piping that is likely to become energized is required to be bonded to the the main bonding jumper at the service disconnecting means. Which piping is likely to become energized? That is up to the representative of the authority having jurisdiction to decide. That person is the local electrical inspector. Some inspectors will except that the Equipment Grounding Conductor (EGC) of the circuit that may be the source of the unwanted current is sufficient bonding. Others will want the bonding conductor sized to the size of the main breaker.

-- Tom Horne

Reply to
Thomas Horne

Trouble is, it's wrong. See my response directly to DanG.

Reply to
Doug Miller

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