You might be right, but grounding won't hurt either.
I now have the commputer equipment plugged in to a UPS, but I don't think the water pipe in the basement is grounded properly. This means that the CATV and phone might not be grounded properly.
How about taking a piece of bare #6 or larger, bond at the same point that you see the phone and CATV being bonded and run to the point that you see your existing panel ground and bond to the wire or to the grounding lug in the panel.
Measure the ohms of resistance on the ground. Here the "rule of thumb" is just drive two rods without measuring as one will seldom if ever pass. 2 often won't pass, but the code says to drive 2 if the first one doesn't pass.
That is the part I am working on. It would be much easier for me to bond this at the point in front of the house than to fish inside walls to get to the panel.
I will take that bet. The second rod I am driving will be in soil 8 feet lower than the existing one. (Not that I have found the existing one yet) :)
gfretwell asked a critically important question:
If every wire in each incoming utility cable is not somehow connected short to the same earthing electrode, then household electronics damage can result. For example, a surge protector inside your telephone NID; where is its earth ground connection? Where does the TV cable make its short connection to earth? Even code now wants all those utilities connected to same earthing electrode.
Sound like you will be supplementing a questionable ground with another #6 AWG and electrodes. This new connection wire must not go up over the wall and down. Although that longer distance is sufficient for code (for human safety), your interest involves something that must also exceed code. IOW the new 6 AWG ground wire should pass through that wall resulting in less length and fewer sharp bends.
Those other utilities also must be earthed 'less than 10 feet' to the same electrodes.
Water pipe must be bonded. Bonded is not for earth ground. That bonding is essential for human safety reasons. Water pipe bonding need not meet the 'less than 10 foot', no sharp bends, etc criteria. But a water pipe must be bonded (not to earth ground) to breaker box safety ground. That bonding serves a different master.
Should all incoming wires not enter at the same location, then one utility offers a suggestion how to single point ground those widely separated utilities:
Even though his post is not relevant to earthing, still, what volts500 suggests for human safety should also be considered since you are examining both earthing and safety ground systems: "Grounding Rod Info" on 12 July 2003 at
The best information on surges and surge protection I have seen is at:
The IEEE guide is aimed at those with some technical background. The NIST guide is aimed at the unwashed masses.
More important than just connecting to the same electrode, the entry protectors for phone, cable, ... must connect with a *short* wire to the ?ground? at the power service. With a large surge, the house ?ground? will always rise above `absolute' ground. You want the power and cable and phone 'grounds' to rise together. The consequences of not having a
*short* connection are illustrated in the IEEE guide starting pdf pageWith your signal entry protectors in the basement, you can?t get *short* connections to the ?ground? at the power service. (But you could run a phone wire from the phone entry protector to the area of the power service, install a 2nd protector, and distribute wiring from there. Same for cable....)
According to NIST guide, US insurance information indicates equipment most frequently damaged by lightning is computers with a modem connection TVs, VCRs and similar equipment (presumably with cable TV connections). All can be damaged by high voltages between power and signal wires.
Complete nonsense. The NEC has *required* the water pipe (10 ft or more buried metal) to be used as a grounding electrode since 1493.
The illustrations do not particularly improve problems of having signal entry distant from the power service.
As others have said, adding ground rods is probably easier than finding where your system is earthed. And the added rods can be near the power service.
I don't question the ground system of the house. I suspect the water pipe under the house. We have never had any problems with electrical equipment in 35 years. Only computer equipment. It is not the power supplies on the computer equipment. It came in through the CATV and hit the modem, router, and 2 motherboards.
After a lightning hit on my computer equipment, I started looking at the way my CATV and phone were bonded to my copper pipe under the house. I have a UPS now.
I can't locate a place where the water pipe is grounded. I don't think it even comes in contact with the ground except maybe where it enters the laundry.
The wall I am going to fish will be almost directly above the water pipe in the basement. The number 6 will have one bend going down the wall. I will then clamp one end to the water pipe in the crawlspace and split bolt the other to the exposed number 6 in the attic. The number 6 will have one bend to attach it to the split bolt.
I will be driving a ground rod at the place where I clamp the panel to the water pipe. I will make sweeping bends, but I don't see why the bond wire can not have tight bends. There will be a direct grounding electrode at both places.
The house is 35 years old and never had any problems with anything other than computer equipment.
This has caused another question I have had in the back of my mind. We have had CATV for at least 15 years and have never had any damage to the TVs.
Of course we don't leave the TVs on 24/7 like we do the computers.
True or False? Having the TV off (not unplugged) lowers the risk of lightning entering through the CATV? I would say false. I am guessing.
You may never have any damage to anything. Surges are chance events.
Most TVs these days are never actually off. If you have a remote control, part of the TV is always on. And only one of the power wires is switched if a TV is actually turned off. That might eliminate surges entering on the power line, but not surges from power wire to cable wire. And, as indicated in the IEEE guide, surges can enter with a voltage between the cable center conductor and shield.
------------- A UPS of the kind likely used in a house does not intrinsically provide any surge protection. The 'protected' load connects directly to the line except during power loss. The same protection that is included in a plug-in suppressor may (or may not) be included in a UPS. Ratings range from junk to very high. UPSs typically do not have very high ratings. Any surge suppressor in the US should be listed under UL1449.
Having 2 ground rods does not mean the rods will be at the same potential if there is a surge. Even if you have a good earth 'connection', the potential at different locations can be different. If you had a modest surge of 1000A earthed through a ground rod with a very good resistance of 10 ohms, there would be a voltage of 10,000V from the rod to 'absolute' earth. As a rule of thumb 70% of the voltage drop from the rod is in the first 3 feet. From the rod to the earth 3 feet from the rod will be 7000V. From whatever is connected to the rod to the earth 3 feet from the rod can be a lot higher with a long wire making the connection.
Suspect your grounding system. You are suffering electronics damage. Therefore a surge is finding earth ground, destructively, via appliances rather than being earthed before entering the building. Either a surge will be earthed on a short connection OR it may find destructive paths to earth via appliances.
The water pipe is buried. However you must remove any electricity from that pipe that might, inadvertently or accidentally, get conducted into those pipes. That is electricity either entering via buried side of pipe OR from inside the building. Bonding makes any voltage on pipes same as on all household wires. No voltage difference? Then no dangerous electrical currents. That 'bonding' is a wire from cold water pipe to breaker box. Bonding is that wire's purpose; to remove electricity from pipes for human safety reasons. That bonding wire must be located to 'pick up' water pipe currents from inside the building and from outside the building.
Some jurisdictions take it one step farther: now require a 6 AWG wire bonded to a steel bathtub. Again, bonding is for human safety; has no relationship to electronics protection.
View your TV cable. When cable companies were purchased with intent to provide reliable service (including phone and internet), then cable guys were completely retrained in earthing. That cable cannot enter a house directly. First that cable must connect short to the single point earth ground - the grounding that you must suspect - the earth ground rods you will be installing. Entire surge protection for cable is a ground block and a 'less than 10 foot' wire to earth ground. No protector is encouraged by a cable company. Wire is completely surge protected without a protector. Wire length is critical. Electricity is not same at both ends of a wire.
Note the repeated references to wire length. Shorter wire length to earth ground is critical to electronics protection. That cable cannot even be connected to a water pipe. Water pipes are no longer sufficient for earthing. Cable must connect directly to the same dedicated earth ground used by telephone and AC electric. Cable's ground wire also must have no sharp bends, short as possible, not bundled with any other non-grounding wire, etc.
Where is the cable earthed? How long is that earthing connection?
Breaker box must be 'bonded' to water pipe AND connected to another ground - earthing electrode. Those are separate grounds. Wire length to water pipe is not critical. Wire length, and no sharp bends, no splices, not inside metallic conduit, etc is critical to earthing. Earthing wire has nothing to do with water pipe 'bonding'. That earthing wire must be one solid wire from breaker box safety ground (bus bar) to earthing electrode; '10 feet or shorter', no splices, separated from other non-grounding wires, etc.
Again, appreciate that water pipe bonding for human safety does not serve the many other functions provided by a different ground: earth ground rods. 'Bond' to water pipes to remove undesirable (dangerous) electricity. Cable TV wire cannot be bonded to outside water faucet. That would make the earth ground connection too long. That would 'dump' electricity into water pipes - unacceptable. Only wire connection to water pipes is 'bonding' to remove electricity from those pipes - essential for human safety.
An older home may have bonded things to water pipes. Once that connection was legal. Bonding (to safety ground something - to dump electricity into pipes) is no longer legal and is dangerous. Earth electrodes may dump electricity into earth. Two different ground wires from same breaker box perform different functions. A connection from breaker box to earth must be 'less than 10 feet', no sharp bends, not inside metallic conduit, etc.
What is this exposed 6 AWG wire in the attic? What does it connect to and what is its purpose?
Drive earth ground rods as close as possible to where AC electric box, teleph> I don't question thegroundsystem of the house. I suspect the water
Lightning seeks earth ground. If conducted to earth via wrong paths, then you have damage. Which incoming paths are you trying to protect? 1) Lightning strike to your chimney? 2) Lightning strike to utility wires out on the street - a direct strike to household appliances? 3) Lightning that enters from earth ground on one side of the house, passes through household appliances destructively, then continues out other side of house back to earth?
Earthing for first above problem is called Franklin lightning rods. A rod properly installed above that chimney would connect lightning to earth without damage. Earthing provides chimney protection. Same protection for an antenna. That antenna must have its own dedicated connection to earth, or an earthed lightning rod protruding above that antenna. How effective is that protection? Quality of the earthing AND how that earthing connection is made determines whether lightning will earth via the lightning rod or will find a better earthing connectcion via something else.
A lightning strike to utility wires (second problem) means each wire entering a building must be earthed where wire enters the building. For example, one of three AC wires must be earthed directly to meet code - for human safety. Inspect that earthing. A bare copper 6 AWG wire must connect from breaker box to an earthing electrode that is best 'less than 10 feet' away. No sharp bends. Ground wire routed separated from other wires. No splices. Not inside metallic conduit. And not over the top of the foundation and down to an earthing electrode. That wire must be shorter and with less bends: directly through foundation and down to that earthing electrode.
Only some requirements are required by code for human safety - understood by all electricians. Some requirements for lightning protection must exceed code requirements - such as no sharp bends, separated from other wires, and 'less than 10 feet'. IOW that ground wire must meet code for human safety, and must exceed code to earth lightning (transistor safety)
To avoid the third problem, all incoming utilities must be earthed to same earthing electrode. IOW all utilities must enter the building at a same location. If your utilities are widely separated, then one solution uses a buried wire encircling the building so that all utilities connect to a common ground system:
Solutions provided for three different lightning paths. Only component always required for surge protection is earth ground. Are both wires for telephone or the other two AC electric wires earthed? Ground those wires directly and get no electric or phone service. Earthing is provided by a 'whole house' protector. During a surge, those ungrounded phone wires are connected directly to earth by the protector. A surge dumped into earth via a 'whole house' protector will not wander inside the house seeking destructive paths through appliances.
Another with an agenda will say anything to avoid that fact. But his own citation says exactly what a protector does. On page 17 (of 24) in
On page 6 (Adobe page 8 of 24):
The 'whole house' protector (when properly earthed) is so effective as to be used in all high reliability facilities. Responsible solutions don't waste money on ineffective solutions such as 'miracle' plug-in devices. That dedicated earthing wire is essential. Telco even installs an effective (earthed) protector on your telephone line, for free. Find the NID box (where their wires meet yours). Inside is a 'whole house' protector. But the protector is only as effective as its earth ground. Is a ground wire from the NID 'less than 10 feet' to the same earth ground used by cable and AC electric?
A protector does not stop or absorb lightning as some will claim. Surge energy must be shunted / diverted / connected / bonded / clamped to earth. Earth is where the energy is dissipated harmlessly. A protector is simply a connecting device to protection. Protection is the single point earth ground.
How do you verify your protection system? Follow those bare copper ground wires from breaker box to find the earthing electrode. Follow the TV cable before it enters to find a 'less than 10 feet' from cable to earth ground. Follow a green or gray wire from telco NID to that earthing electrode. This single point earth ground is a 'secondary' protection system.
Also inspect your 'primary' protection system:
Other grounding for human safety was described by volts500 in "Grounding Rod Info" on 12 July 2003 at:
Not just the same electrode. The phone, cable, ... entrance protectors must connect with a *short* wire to the ground at the power service. Widely separated utility entrances can produce a high voltage between signal and power wires that can damage equipment connected to both. The IEEE guide provides an example starting pdf page 40. I see no reason to believe the schemes in w_?s link would significantly help. The IEEE guide says that if the utility entry points are distant "the only effective way of protecting the equipment is to use a multiport [plug-in] protector."
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 (or stopping or absorbing). The guide explains earthing occurs elsewhere. (Read the guide starting pdf page 40).
My only agenda is accurate information. That is why I posted links to reputable guides from the IEEE and NIST. Read them for yourself.
What does the NIST guide really say about plug-in suppressors? They are "the easiest solution". and: "Q - Will a surge protector installed at the service entrance be sufficient for the whole house? A - There are two answers to than question: Yes for one-link appliances, No for two-link appliances [equipment connected to power AND phone or CATV or....]. Since most homes today have some kind of two-link appliances, the prudent answer to the question would be NO - but that does not mean that a surge protector installed at the service entrance is useless."
Some of what w_ says is quite good. What he says about plug-in suppressors is nonsense. For reliable information on surge protection read the IEEE and/or NIST guides. Both say plug?in suppressors are effective.
Then read w_?s sources that say plug?in suppressors are NOT effective - oops - he doesn?t have any sources.
? bud--
w_ is a nutcase on this issue. The NEC has *required* water pipes (10 ft or more buried) to be used as a grounding electrode since 1494 (is that better Smitty?)
?Remove electricity from those pipes? is technical illiteracy.
Continued nonsense. When a water pipe is used as a grounding electrode, phone and cable protector ground wires (among other things) can be connected to it in the first 5 feet inside the building. (This is not likely to result in a good ?single point ground?.)
The most important feature of a ?single point ground is a *short* ground wire from phone, cable, ... entry protectors to the service panel ground. (The service panel ground is the magic point because the neutral and ?ground? are tied together at that point - it is the ground reference point of the power service.) If the wire is not short, high voltages can develop between power and phone, cable, .... When the ?ground? rises from ?absolute ground? with large surge current, you want the power and phone and cable ?grounds? to rise together.
Francois Martzloff, who was the NIST guru on surges and wrote the NIST guide, has written "the impedance of the grounding system to `true earth' is far less important than the integrity of the bonding of the various parts of the grounding system."
The way I read Terry?s description, the phone and cable protectors are at significant distance from the power service, as is the case in many houses. In that situation, the IEEE guide says "the only effective way of protecting the equipment is to use a multiport protector."
Hate to tell you this but strikes nearby come up through your grounding system to take out a lot of electrically fragile stuff, especially CMOS (like the above).
Go with a quality whole house surge protector at the breaker box and also individual protector strips at point of use. Most small protectors use a solid state device similar to a zener diode that shunts excess voltages to ground (and vice versa).
Even better would be a UPS sized for your equipment. I use one UPS per computer (looks like you have more than one). Two brands I have used are APC and CyberPower. There are probably more brands out there. They are very cheap insurance. Find them at Office Depot, Circuit City etc.
Most of the UPS units now available on the consumer market are of the switching type that transfer the load to the battery powered inverter before the output of the computer's power supply can fall low enough to cause disk damage or data loss. That is no were near fast enough to effect most surges and spikes. In order for the UPS itself, rather than any built in filtering or Transient Voltage Surge Suppressor, to provide protection from transient power events it has to be of the continuous duty type were the battery is always in line and the supplied Ac power is used to recharge the battery. If the battery is always in line it is one massive sink for sudden voltage fluctuations. You can get the same TVSS benefits of a switching UPS by using a high quality TVSS protector.
-- Tom Horne
HomeOwnersHub website is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.