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Cannot see router

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August 6, 2010 1:18:55 PM

Hi Everyone,

I have a belkin N wireless router hooked to a cable modem. Last night a storm hit and my two PCs (connected via cat 6 to the belkin) were found with the fans on, but no other sign of life. I rebooted, and both came up OK. The internet was down (from the status lights on the time warner modem, called and it was because of the storm, they're fixin it). However, my LAN is also down: I cannot see either computer OR the belkin router (cannot even ping). I thought the router was dead but:

My wireless laptop CAN see the router AND if I turn off the wireless connection and wire it via cat 6 it can still see the router. But neither of my two pcs can see the router. They give me a 'network cable unplugged' error.

I have tried to reboot, plug and unplug the router, etc. I have a surge protector, but is it possible that a surge came through the cat 6 cable and fried my ethernet adapters in BOTH pcs? Never heard of that, sounds far fetched, but I cannot think of anything else. Windows says that the ethernet device is working properly, though that may not mean much. I'm not at home now (no internet) so I cannot check anything until tonight.

Any help is very welcome...

Cisco

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August 6, 2010 3:47:02 PM

ciscocbee said:
I have a surge protector, but is it possible that a surge came through the cat 6 cable and fried my ethernet adapters in BOTH pcs? … Windows says that the ethernet device is working properly, though that may not mean much.

Windows can only say the motherboard CPU is talking to an NIC CPU. Says nothing about the NIC talking to ethernet.

To have damage, well, it is electricity. There must be an incoming path. And most be an outgoing path to earth. Nothing - and grab this sentence like it was from the Bible - nothing stops or blocks a surge. Surge – ie direct lightning strike - without damage is routine. Even a protector must not fail. But nothing stops, blocks, or absorbs a surge as plug-in protectors claim in advertising.

That protector may have contributed to damage; made damage easier. Read its numeric specifications. Where does it list protection from each type of surge? It doesn't. It is a surge protector. It is not surge protection.

Incoming path is something that was temporarily connected to a cloud. Outgoing was something that connects to earth. If Time Warner has properly installed the cable, then cable connects short to earth (ie 'less than 10 feet') where it enters the building. Inspect it. If not, TW must fix a code violation. If yes, then no surge entered via cable. Cable can only be the outgoing path.

Once inside a building, then a surge goes hunting for earth ground - destructively. Nothing stops or blocks that hunt – as stated so bluntly above. Obviously, you let energy enter. The hunt probably found earth destructively via computers and other related equipment. Outgoing to earth maybe via cable wire. That is the most common reason for damage to computers, cable modem and network equipment. Damage most often on the cable side when a surge enters on AC mains. Damage directly traceable to surge energy permitted inside the building.

Noted earlier - nothing stops or blocks a surge. If no one 'whole house' protector was earthed on AC mains, then you all but invited a surge to hunt for earth destructively via all household appliances. Only some appliances make a better connection to earth - destructively. A 'whole house' protector is so effective because it makes the always required - no exception - short connection to single point earth ground.

A protector is only a connecting device to the protection. The protection is single point ground. Where does hundreds of thousands of joules harmlessly dissipate? In the only protection system component that does surge protection – single point earth ground.

Either a surge harmlessly dissipates outside a building. Or that energy must hunt for earth destructively via appliances. Yes, repeated again because so many people educated by scam plug-in protectors do not get it. Either a protector makes the short connection (ie ‘less than 10 feet’) to earth ground. Or it does nothing. Maybe even makes damage easier.

That protector either did nothing or may have made damage easier. That protector is not protection. A protector too far from earth ground and too close to appliances is a profit center.
August 6, 2010 4:30:05 PM

You appear to be very passionate regarding surge protectors. It is good to be passionate about things.

I guess I really don't understand much about surge protectors. I thought they operated by using semiconductors to pass voltage TO ground if it 'surges' above a certain level (I would guess 120 volts in this case). You are saying that this is not possible though?

Anyway, the point of my post was more to figure out if my troubleshooting is correct and it is my ethernet card that is blown, but I do always enjoy learning new things.


Cisco
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August 6, 2010 4:56:04 PM

ciscocbee said:
Anyway, the point of my post was more to figure out if my troubleshooting is correct and it is my ethernet card that is blown, but I do always enjoy learning new things.

First identify the path to earth. Now you have a list of components that are damaged or may be overstressed - ie fail a month from now.

That surge is an electric current. It had an incoming and outgoing path. Connect the dots. Then learn where to inspect for additonal current or future failure.

In the computer's case, that is why more responsible computer manufacturer provide comprehensive hardware diagnostics for free on the hard drive, on a CD, and on their web site. And why Windows also reports failures in the system (event) logs and in Device Manager.

NIC - many layers to a network connection. Your concern is a lowest level - hardware signaling. What lights on both ends of the ethernet cable report. If the transmitters and receivers are exchanging digital waves, then the light says so. Those waves exist even when no data is flowing. If not, an NIC computer could be good - but its ethernet transimitter / receiver is still damaged. And that is a dot in the path from cloud to earth.

Do not just fix hardware. Surges never cause damage when a homeowner is informed. Also fix a defective protection system. That also means connecting the dots. Discovering an incoming and outgoing electrical path that created completely unnecessary damage.

Routine is to have direct lightning strikes - and no damage.
August 6, 2010 5:05:35 PM

ciscocbee said:
I guess I really don't understand much about surge protectors. I thought they operated by using semiconductors to pass voltage TO ground if it 'surges' above a certain level (I would guess 120 volts in this case). You are saying that this is not possible though?


Surges are a massive current source - not a voltage source. That means voltage will increase as necessary so that a constant current always flows. Anything that might stop that current simply suffers an increased voltage until it is blown through. No protector stops or blocks surges. But that myth gets the most naive among us to recommend scam protectors.

Take a $3 power strip. Add some ten cent protector parts. Sell it for $7 in the grocery store. Or attach a Monster Cable name to it, add some expensive paint, and sell it for $80 or $150. Many foolishly assume you get what you pay for.

For over 100 years: the effective protector always makes that short (ie 'less than 10 foot') connection to earth. Not just any earth. Single point earth ground. No earth ground (ie all plug-in protectors) means no effective protection. And no protection claims in its numeric specs.

Again, follow the dots. Damage exists because that current hunted for earth destructively via electronics. Voltage increased as necessary so that the current would blow through some appliance to earth.

What does a (maybe) 300 volt protector do? 6000 volts on the black (hot) wire. Protector simply puts 5700 volts on the other white (neutral) and green (safety ground) wire. It simply gave a surge more paths to find earth destructively via any nearby appliance.

An IEEE brochures shows just that. No ‘whole house’ protector was earthed. So the plug-in protector earthed a surge 8000 volts destructively through a nearby TV. Not the TV plugged into the protector. Protector will earth a surge through any nearby appliance. In this picture, 8000 volts destructively through another nearby TV – the better connection to earth.
August 6, 2010 5:17:17 PM

Hmm... OK. I should have an earthed whole house protector. I just bought the house and the electrical system was inspected and found up to code. In NC code includes grounding requirements. There is also lightning protection for the house (though this will not of course protect from lightning hitting electrical wires nearby and causing surges. Is this what you mean by a 'single point earth ground'?
August 6, 2010 6:39:39 PM

So I did a little reading and from what I understand the ground plug should go to a functional earth ground, so I still don't understand why the surge protector doesn't work. You have a surge, the surge protector does not 'block' the surge, just shuttles the excess current to ground. It should not go through a TV or other device since my ground should be the preferred path (less resistance). What am I missing?
August 6, 2010 10:49:17 PM

ciscocbee said:
Hmm... OK. I should have an earthed whole house protector. I just bought the house and the electrical system was inspected and found up to code. In NC code includes grounding requirements.

Earth for human safety means a ground meets whatever code was in place when the house was built. Earthing for surge protection means earthing must both meet and exceed post 1990 code. Your inspection was only about human safety.

Code defines human safety. Surge protection is about transistor safety. Transistor safety means both meeting and exceeding code requirements.

Receptacle is called equipment ground (safety ground). Completely different from the ground being discussed - earth ground. See repeated references to 'less than 10 foot'? A number that says why wall receptacle grounds are not earth grounds.

More numbers - 50 feet of wire connects a wall receptacle to a breaker box. That wire is less than 0.1 ohms "resistance". Same wire is something like 120 ohms "impedance" to a surge. What happens if a plug-in protector attempts to earth a tiny 100 amp surge? 100 amps times 120 ohms is something approaching 12,000 volts. Will a surge travel through a 12,000 wire? Of course not. Energy will hunt for other paths to earth destructively via nearby appliances.

An IEEE brochure (discussed previously) demonstrates that fact. The figure shows a plug-in protector earthing a surge 8,000 volts destructively via a nearby TV. Number is right there in the figure. 8,000 volts because a wall receptacle safety ground is too far - much more than 'less than 10 feet'.

Discussed was 'less than 10 feet'. Sharp wires bends, splices, wire inside conduit and other factors further increase impedance. Further subverts protection. More reasons why a wall receptacle safety ground does not do effective earthing.

Telcos, connected to overhead wires all over town, suffer at least 100 surges with every thunderstorm. How often is your town without any phone service for four days while they replace their switching computer? Never. Telcos locate each protector at earth ground - as close as possible. And up to 50 meters distant from electronics. Impedance between protector and electronics increases surge protection. Superior protection means a protector is within feet of earth ground. And distant from electronics. Why? Wire impedance.

Code does not address transistor safety. Codes only address human safety. Transistor safety means you must both meet and exceed earthing requirements.


Single point ground is just that. Any wire that enter a structure must first connect short (ie 'less than 10 feet') to an only and best earthing electrode. The single point earth ground. A professional's application note demonstrates the principles:
http://www.erico.com/public/library/fep/technotes/tncr0...

Any wire that enters either structure must first be earthed. That means all wires enter at a common location - the service entrance. Even underground wires must be earthed before entering.

Well, all this is probably completely new. Most have never heard of a 100+ year old, well proven science that even explains why Ben Franklin lightning rods work. You will not understand it in one read. Especially if myths that promote plug-in protectors were learned previously. Unlearning those myths can make learning this well proven, 100 year old solution difficult. Multiple rereads.

August 9, 2010 4:26:37 PM

Still trying to figure this out. Sorry if I'm a little slow...

Questions:

1. Why does s wire with 0.1 Ohms resistance go up to 120 Ohms impedance during a surge? I thought that prorogation of AC at higher voltages was more efficient than lower (why we use step up transformers to bring up the voltage on the transmission lines). I know that there are non-linear conductors that do change resistance with change in voltage or current, but copper wire is not one of them.

2. Even if the impedance goes up, it should still be lower than going into my TV. After all, the first is a wire to ground, the other is a TV to wire to ground. An extra stage of resistance, but ending up in the same place.

Thanks for the help.

BTW I replaced my ethernet cards and now my LAN is up and running. My router still isn't working so I went to the time-warner store and got it replaced. Still doesn't work, so the cable into the house seems broken. They're coming to fix it Tuesday.
August 9, 2010 5:24:06 PM

ciscocbee said:
Questions:
1. Why does s wire with 0.1 Ohms resistance go up to 120 Ohms impedance during a surge?
2. Even if the impedance goes up, it should still be lower than going into my TV. After all, the first is a wire to ground, the other is a TV to wire to ground. An extra stage of resistance, but ending up in the same place.

When 120 ohms impedance exists, the 0.1 ohm resistance is still 0.1. Surges are radio frequencies. That means new factors come into play such as described by the Telegrapher's equation. http://en.wikipedia.org/wiki/Telegrapher_equations And why voltages are so different at various sections of an antenna wire. Voltage on one part of a transmitter antenna wire can be hazardous while the other end may be completely safe.

You need not know these details. Only that those details say why a protector must connect short (ie 'less than 10 feet') to -not just any ground - single point earth ground.

Either a surge harmlessly dissipates outside a building. Or that energy must hunt for earth destructively via appliances. An IEEE brochure shows a plug-in protector earthing a surge 8000 volts destructively via an adjacent TV. Impedance meant AC wires were maybe 12,000 volts - described earlier. So voltage rose above 8000 volts - so that the surge could obtain earth destructively via that TV. Which appliance was damaged easier? Which appliance was easiest to blow through the earth ground? Once that energy is inside a building, nothing stops the hunt.

Surges are a constant current. That means voltage rises as necessary for that current to flow. In this case 8000 volts. And once the arc, destruction, etc has created a new path through that TV, voltage drops. It no longer needs 8000 volts to flow that current through the TV. So even more current flows through the TV - less going anywhere else. The TV acted a protection for other appliances - and that power strip protector.

Again, details that describe many ways that a surge can obtain earth destructively via appliances. Again, you need not fully understand them. But you must understand what it means. If you let a surge inside the building, then it will hunt for earth destructively via appliances - with or without any plug-in protector or UPS.

Wire impedance is why a protector must connect so short to earth. And why that ground wire must have no sharp bends, no splices, not inside metallic conduit, etc. Wire impedance is also why facilities without damage put the protector distant (ie up to 50 meters) from electronics.

Follow a bare copper ground wire from your breaker box. Does it go up over the foundation and down to an earth electrode? Then protection from a ‘whole house’ protector may be compromised. That wire is too long. Has sharp bends going over the foundation. Is adjacent to other non-ground wires. That ground wire must go through the foundation and down to the single point earth ground. Why? Impedance must be lower. Resistance is not relevant (the Borg got it wrong).

August 9, 2010 5:35:11 PM

ciscocbee said:
My router still isn't working so I went to the time-warner store and got it replaced. Still doesn't work, so the cable into the house seems broken. They're coming to fix it Tuesday.

Other modems (ie DSL) have a server inside. You simply bring up that page to see important parameters such as signal strength (or even if a signal exists) from the cable. For example, the DSL radio wave can exist. But the router's server give a dB numbers that says the signal is too low.

Cable companies cannot be bothered to provide such useful information. If you had it, then you were not replacing parts until something worked. You saw the number, then knew exactly what needs fixing. Or you posted that number so that the better informed could reply with an accurate solution immediately. But cable companies cannot be bothered to provide that server page - those so important numbers.

The cable guy will come with a meter to measure the same dB -if he knows his stuff. Some linemen buy even better ones (for $5000) out of their own pocket. Because numbers such as signal strength in dB is the first thing one views to find before fixing a problem.

Be sure to have him inspect the cable earth ground. As you now know, that connection from the cable to single point ground (also used by telephone and AC electric) must be short, no sharp wire bends, etc. If not, he may have to drop the cable down to near that ground, before the cable rises back up to enter the building. Not grounded to any other ground wire or faucet. It must connect direct to the same ground rod used by AC electric – at that ground rod. All ground remains separate until they meet at the single point earth ground.

August 9, 2010 5:39:25 PM

Do you have a link to that IEEE brochure? I don't think you gave it before.

Thanks!

Cisco
August 9, 2010 5:49:43 PM

OK, I'll get the cable guy to do that.
August 9, 2010 9:45:02 PM

Sigh. I don't think I'm too bright. I still don't get it. Please help me understand (you've been very patient so far).

Connecting the dots:

So I get a surge of current through my lines. Now if everything in the house (and all surrounding houses) are unplugged, it is dissipated though the ground attached to our houses, as well as the transmission ground at the transformer.

If things are plugged in, the appliances cannot accept the current at the regular voltage, so the voltage goes up. When it hits ~300 volts (still pretty low) the resistance of the semiconductors in the surge protector drop to near zero, allowing the current to pass to ground.

If what you say is true, then the impedance is too high for this to happen and instead it goes through my TV as a 'better' route to ground. But (again connecting the dots) what is this better route to earth ground? If it goes back through the grounding on the TV it would still have to go through the inadequate longer than 10 feet ground used by the surge protector. What other better (lower impedance) route to ground does it have? It sure didn't arc 2 ft to the wood floor and then arc through the floor to a pipe and then to ground. I think I would have noticed.

So why would it make an additional step to overcome the resistance in the TV just to get to the same place as it would have got to by shunting to ground via the zero resistance (at that voltage) surge protector?

So confused...
August 10, 2010 12:57:25 AM

ciscocbee said:
If what you say is true, then the impedance is too high for this to happen and instead it goes through my TV as a 'better' route to ground. But (again connecting the dots) what is this better route to earth ground?

If energy is earthed outside the building, than it has zero reasons to overwhelm protection inside any appliance inside the building. It has zero reasons to take a difficult path to earth via appliances. It need not increase voltage to maintain the current flow.

All appliances contain serious protection. A surge earthed outside the building does not overwhelm that internal appliance protection.

So we did an autopsy. All computers have superior protection in a power supply. But two powered off computers were on power strip protectors. That black (hot) wire surge was connected to the green (safety ground) and white (neutral) wires. Now the surge was on all wires and connected directly to the motherboard. Power strip protector compromised protection in the computer – bypassed the power supply. Gave the surge more wires to find earth - destructively.

Surge current was outgoing via NICs. Found a third networked computer. Through that NIC, into motherboard, out via modem, and to earth via phone lines. A best path to earth is a phone line. All phone lines have an earthed ‘whole house’ protector. Now we have connected the dots.

Did the surge also take other paths to earth? Does not matter. Many transistors were damaged by a direct lightning strike because energy was permitted inside the building. Damage was completely unnecessary. Plug-in protectors (no earth ground) made damage easier.

Without a connection to earth, that surge current had to increase voltage to get inside and blow through appliances. Voltage always increases as necessary so that the same current always flows.

Damaged were ICs on the NICs, and standard 56K modem damage. Surge was through a PNP transistor that drives the modem’s off hook relay. Into the relay's coil. Out via the relay's wiper. To earth ground via phone line. Standard error message was "No Dialtone Detected".

Even though current passed ‘coil to wiper’, that relay was undamaged. But its PNP transistor failed. Standard damage. Burned out PNP transistor means that modem could not connect to phone lines. We replaced every IC and that PNP transistor to make all computers work – without any future failures. (So much for another myth about lightning causing irrepairable damage.)

Just another example of how surges seek earth once anyone lets a surge inside the building. If energy is inside anywhere, then it will go hunting for earth via appliances. And it will increase voltage as necessary to blow through anything that might try to stop a surge.

It passed through motherboard without damage. Obvious once the path is traced. It did not find earth destructively via other network computers. Does not matter where else that surge current went. It found earth ground destructively because the homeowner did not earth one 'whole house' protector. And because those two power strip protectors bypassed protection – bypassed power supplies. Once inside, that current increased voltage as necessary to flow though existing appliance protection.

All appliances already contain protection superior to what may be attached to its power cord – ie power strip protector. Your concern is a surge that will overwhelm internal protection. Sometimes a power strip protector can even make damage easier – the above example. But the only solution always used where damage can never happen – always connect a ‘whole house’ protector as short as possible to single point earth ground. Then a surge does not increase voltage to flow current inside the house. Then energy is not inside hunting for earth destructively via appliances.

August 10, 2010 12:21:51 PM

Hmm... OK.

One other question: Are the telegrapher's equations for AC and DC, or AC only (they talk about impedance which I thought was only relevant to AC circuits). I assume the surge is DC (and overwhelms any residual AC component) so I'm just curious if they apply. There should be no rf component to a lightning surge I assume.

Best solution

August 10, 2010 3:31:26 PM
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ciscocbee said:
I assume the surge is DC (and overwhelms any residual AC component) so I'm just curious if they apply. There should be no rf component to a lightning surge I assume.

It was an old joke in engineering school. A "DC spike". Fact that the voltage and current switches means it contains many AC components. Lightning is radio frequencies. Can be heard on AM (longwave) radios.

The telegraphers equation was also about DC batteries slowly switched on and off by a switch. The telegrapher's key. Key held down for long (many millisecond) periods. That was also a "DC spike".

The underlying concept taught in math - Fourier Series.
August 10, 2010 3:52:06 PM

OK. Neat.
August 11, 2010 12:34:20 PM

Update: Time Warner (oh how I hate them) finally came to fix the problem after blowing me off for the first appointment (and losing 1/2 day vacation in the process).

Seems that lightning struck where the cable drops from the power line. The cable ground was severed (actually the entire cable was severed) and the surge went through into my poor ethernet adapters. Guess the surge protector was a non issue in this case.

Westom: I did ask the tech guy about the cable ground near the house. He said that it is grounded, but because the lightning entered both ground and the inner co ax wire, the ground was overwhelmed (same thing you were talking about before, the distance from the power line to the house where the cable is grounded is much more than ten feet) and the rest of the surge went through the cable into my router and from there to my ethernet cards.

Not sure how you protect against this. I guess you could ground the cable every ten feet until it gets to the house, but that would be quite ugly. And possibly a tripping hazard.

Oh well.

Cisco
August 11, 2010 12:35:59 PM

Best answer selected by ciscocbee.
August 12, 2010 12:26:14 AM

ciscocbee said:
Westom: I did ask the tech guy about the cable ground near the house. He said that it is grounded, but because the lightning entered both ground and the inner co ax wire, the ground was overwhelmed
If that ground was overwhelmed, then a ground rod is now loose in the earth. Remember, he is a lineman. He typically has no electrical knowledge . He is only told what he must do. Most do not know why.

If the connection from single point ground to cable was more than ten feet, then he removed and rerouted the cable to be only 3 feet to earth. That assumes he knew why and therefore understood why all that work is so important. Most lineman are told what to do. But without proper electrical knowledge, do not know why ‘less than 10 feet’ (or every foot shorter) is that critical. Therefore he probably could not be bothered to reroute the cable.

Surge down a center conductor is (except in special cases and yours is not one) a popular myth. If the shield was properly earthed, then no surge was inside the cable. Engineering reason why from Richard Harrison, a well respected industry professional:
> Coax, inside, rejects common-mode propagation of lightning energy.

In short, only reason why energy might be inside the cable is because the entire cable was not properly earthed. Fix the earthing - then no surge energy inside the cable.

Better earth ground mean no energy enters a building. Why would a surge enter via cable, then through the ethernet port, then go nowhere? Most surges are outgoing via the cable. Then may also do additional damage to the coax wire.

Defined previously is everything necessary so that direct lightning strikes never cause damage inside the building. Immediately obvious - he did not fix a completely defective earth ground. And, well, how many earth ground rods do you have? Are multiple rods still firmly in earth - cannot be shaken?

For some reason, energy had to increase voltage to blow through ethernet ports rated at least 2000 volts. To increase voltage that much because the earth ground was virtually non-existent. Which is why most Time Warner damage is incoming from the house via AC mains. Yes, ethernet ports are typically that robust. Says how massive energy inside the building was to find earth destructively via that port. Says how defective your earthing was - and apparently still is.

Fix the mistake. The objective: learn from this event. Fix an obviously defective earthing system. So far, I hear nothing that says anything was fixed. Start by going to Lowes. Ask him to put your hand on a 10 foot copper clad ground rod and on 6 AWG bare copper wire. Even feel the weight of that rod. You will need that 'feeling' to inspec what you have in the ground. Buy nothing. Then go home and see what you really have. That is how a solution might begin.
August 12, 2010 3:19:28 PM

Hey. The brochure you mentioned is IEEE-1100-1999, correct? I just downloaded all 424 pages.

From what I understand though, I still need a surge protector to shunt the surge to ground, I just need a good ground. I think the category C surge protectors are what they recommend. After all, you can have all the single point less than 10 ft earth grounds you want, but if there is no mechanism for the surge going through your mains (from the lightning that hit the power lines down the street) to get to the ground, it will still blast through your electronics.

In fact, it could be even worse with a good ground since it will be that much more eager (I suppose differences in potential could be labeled 'eagerness' of electrons - whoa, good alliteration if I do say so myself) to get to the ground through the electronics.

So it still seems surge protectors are necessary, but that they connect to a good ground, correct?
August 12, 2010 3:21:41 PM

Quote:
Engineering reason why
from Richard Harrison, a well respected industry professional:
> Coax, inside, rejects common-mode propagation of lightning energy.

Why is this? It is a metal conductor after all. Do you have links to Richard Harrison regarding the underlying mechanisms?

Thanks

August 12, 2010 4:57:34 PM

ciscocbee said:
In fact, it could be even worse with a good ground since it will be that much more eager (I suppose differences in potential could be labeled 'eagerness' of electrons - whoa, good alliteration if I do say so myself) to get to the ground through the electronics.

Those categories are really only what the appliance may expect to see if energy does not obtain earth before entering the building. Category basically is a designer's criteria for estimating how robust his design must be.

Design a protection system based upon current. Voltage is only a symptom. And design for where that current flows. A better earth ground means current goes there - is harmlessly dissipated. Means voltages remain lower.

That current is going to flow no matter what you do. Better earthing does not mean more current or more surges. Better earthing means that constant current does not create a higher voltage.

To better understand, start with a wooden church steeple. Wood is an electrical conductor. Lightning (typ 20,000 amps) seeks earth via wood. Wood is not a superior conductor. So 20,000 amps creates a high voltage. 20,000 amps times a high voltage is high energy. Church steeple damaged.

Franklin installed lighting rods. Lightning rods (like protectors) do no protection. Rods only connect lightning to what does protection - earth ground. Using a conductive metal wire, 20,000 amps creates a low voltage. 20,000 amps times a low voltage is low energy. No damage.

Lighting had no reason to conduct via wood. Lightning has no reason to conduct via household appliances. If provided a superior (electrically shorter) path to earth, then no large voltage exists. No massive energy to destroy a wooden church steeple or household appliances.

To explain that coax cable concept, first learn about longitudinal and normal mode electricity. And learn concepts taught in electromagnetic wave theory. Even parameters in the telegrapher's equation and how your cable connects line amplifiers further explain why a protector to the center conductor is unnecessary for your situation. Why earthing a shield (and that includes the cable companies earth ground to their nearby amp) is so much more important. And why that protector to the center conductor must make the always required short connection to earth to be effective.


The IEEE brochure is not the Emerald Book. Relevant picture is on Page 42 (of 61) Figure 8. When a surge is not earthed, a plug-in protector connects that current 8000 volts destructively via TV2. Energy was permitted inside. It hunts for earth via appliances:
http://www.lightningsafety.com/nlsi_lhm/IEEE_Guide.pdf

Voltage must rise maybe 10,000 volts both inside and to earth beneath that building. If different, then 8000 volts can be created destructively inside the TV. Its not about voltage. Surge protection is always about where that current will flow. It current flows to single point ground beneath a building, then earth at 10,000 volts means house is also at 10,000 volts. And no current flows inside the house. That current will flow no matter what tries to stop it. The current is constant. Voltage will increase as necessary to let that constant current flow. Current flowing directly to earth does not create a higher voltage inside the house. Protection is always about where the current flows so that no high voltage is created.
August 12, 2010 8:23:04 PM

The IEEE brochure on pg 42 just says that you need a surge protector for BOTH TVs (and the co-ax cable), not just the one. It still recommends surge protectors.
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