Whole house phoneline surge protection

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snipped-for-privacy@optonline.net wrote:

It's not "free", per se. It's already been paid.
Also, your use of the word "should" is right on. It's a crap shoot if the hapless subscriber can talk the repair line answerer into dispatching a service technician on a WORKING line.
If the telco tech finds NO trouble on THEIR line, and the service is NOT covered by an inside maintenance plan (subscription feature), a significant (~$75) charge could apply.

That goes without saying. (Anything is possible.)
I encountered the occasional ~20-year-old service where the system was NEVER bonded.
There was a hand-coil of solid ground wire to MAKE the run but it had never been completed. This was typical of a new house that was "pre-wired" by the phone company BEFORE the plumbing or electric had been installed. One can assume that the technician that left the service UNgrounded had some intention to return to finish the job. He never made it back. I know the feeling. I occasionally fixed them. Of course, I never revealed my discovery to the property owner.
In today's "legacy" (incumbent) telephone world, there is NO "going back" to finish a job.
IF telephone plant gets NO respect at all, its grounds get even less.
Telephone companies have been around only slightly fewer years than railroads. (132 years and counting)
They had all their liabilities covered YEARS before there was any talk of divestiture and breaking-up the Bell System monopoly. They will NOT replace customer equipment.
It has been my experience that an in-line suppressor circuit caused a dial-up connection to degrade and slow down. Beware. Good luck.
--
:)
JR

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On Jun 6, 4:24 pm, snipped-for-privacy@invalid.com wrote:

Appalling are the large number of Americans who don't know how electricity works. Talking to the telco phone banks is like asking an English major why a light bulb works. They don't know. Only way to get problems solved is to get the lineman - the only telco service people who know how electricity works. You can spend hours explaining the problem to a phone droid. The lineman takes a look and solves it in minutes.
This problem is so acute that Verizon recently created a VP of customer service.
If you did not have earthing, then you had no surge protection. AND if all incoming utilities are not earthed to the same point (directly or via a protector), then damage will still result. Nobody is 'required' to solve surge damage due to multiple earth ground rods. However one utility discusses the problem AND solutions in "Preventing Damage Due to Ground Potential Difference" at: http://www.cinergy.com/surge/ttip08.htm
Bottom line: you (the homeowner) is responsible for providing proper earthing. If you don't provide sufficient earthing, then inadequate earthing by each utility may be installed. Any utility wire in any cable that enters without a connection to earth ground can earth lightning, destructively, through appliances. One common path to earth is incoming on AC hot (black) wires, and destructively to earth via telephone appliances and that telco installed 'whole house' protector. All incoming wires must connect to that same earthing electrode - the single point earth ground.
This is America. The homeowner is ultimately responsible for getting all utilities to properly earth. How good is that earthing (meaning how good is that protection)? Well, what single point earthing electrode(s) did you install?
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Code says the second ground rod must be located at least 6 feet away.
As long as a wire from NID (demarc) to earth ground rod is sufficient gauge (14 or 10 AWG), then increasing wire gauge does little to create better earthing. Again, the word is impedance. Thicker wire means lower resistance; not lower impedance. Lower impedance is more important. Lower impedance is best created by making that earthing connection shorter, no sharp bends, no splices, etc. Increasing wire gauge provides minimal if any significant improvement. Shorter wire length is more important than a thicker wire.
Better protection means a shorter connection to earth and a longer distance to the protected appliance.
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Wrong.
Nick
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As far as I know (from way back in college) impedance differs from pure resistance only when there's one or both of inductance and capacitance.
Of course I could be wrong.
Anyway, it'd be interesting to know how it relates to grounding.
Thanks!
David
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David Combs wrote:

. A wire has resistance and inductance. At power line frequencies the inductance can generally be ignored.
Surges are very short duration events. That means they are high frequency events. Wire inductance can not be ignored, and is more important than resistance in determining the impedance of the wire.
The impedance of the ground wire in a branch circuit limits the effectiveness of a plug-in suppressor for earthing a surge. But the IEEE guide explains plugin suppressors do not work primarily by earthing a surge.
But impedance of branch circuit wires also greatly limits the surge current (and thus energy) that can reach a plug-in suppressor.
--
bud--

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On Jun 29, 11:29pm, snipped-for-privacy@panix.com (David Combs) wrote:

The 'top of the front page' articles in Electrical Engineering Times were entitled "Protecting Electrical Devices from Lightning Transients". Low wire impedance is defined and required for better surge protection at: http://www.planetanalog.com/showArticle.jhtml?articleID=201807830
What undermines a protector? Earthing wire that is too long, sharp bends, splices, inside metallic conduit, bundled with other non- grounding wires, and not using a single point earth ground. Many of those compromising installation mistakes increase wire impedance. Effective protection requires a low impedance connection to earth. Protection can be supplemented by increasing impedance between protector and electronics. 50 foot of romex between the 'whole house' protector and an appliance means even better appliance protection. That distance, all those sharp bends, multiple splices, etc increase wire impedance.
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wrote:

If the first ground rod is ok and about 8 feet long, it will do almost no good to install a second ground one or two feet away. I think the code is 6 feet and maybe a #6 wire. Anyway no mater what the code, the rods need to be atleast 6 feet apart to get the benifit out of two rods. The rods need to be installed almost as far apart as they are long.
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On Jun 6, 3:24pm, snipped-for-privacy@invalid.com wrote:

I have a rural house that suffered several modem failures from lightning surges also. I got the same story when I asked them to check the grounding. They said it was properly grounded at their junction box. Problem was the junction box was 635' from my residence. I drove a 10' ground rod adjacent to the demarc box on my residence and connected it directly to their ground terminal. Haven't lost a modem or phone since. Some battles are just not worth fighting!
Red
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bud-- wrote:

bud, I'm not trying to get in the debate you have with you know who. This is meant as a sincere question :)
Can you explain in layman's terms what "clamping" means. You say it doesn't stop, absorb, divert--so exactly what does it do? To me those things would be the only thing I can think of that could fit the word "clamping". Again, a sincere request to explain exactly what clamping means in a way a layperson could understand.
-- John Ross
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Clamping means limiting the voltage difference between different circuits or conductors. When MOVs in a typical surge protector turn on, the voltage difference between the various conductors is kept to the turn-on threshold of the MOVs, which is typically a few hundred volts. So, the appliance, instead of seeing a differential voltage of say 2000 volts between say hot and neutral, only sees a maximum voltage of 350 volts, which is survivable. Plug -in surge protectors have this protection between the various conductors passing through them, AC, phone, etc.
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My *next* stupid question: what's a MOV?
Thanks,
David
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David Combs wrote:

. http://en.wikipedia.org/wiki/Varistor
MOV = Metal Oxide Varistor A varistor is a resistor with a resistance that is not constant.
If you know what a Zener diode is, a MOV is like a bidirectional Zener diode.
A MOV tries to limit the voltage across it. As surge voltage rises above a characteristic clamp voltage rating, the current rises very rapidly. That can result in thousands of amps through the device (for a very short time). Most surge suppressors are based on MOVs because MOVs have high current and high energy dissipation ratings in a small package, and they are cheap.
(Clamp voltage) times (current) times( time) equals energy that is absorbed by the MOV as heat. That can produce some damage.
MOVs have an energy rating, which is the max energy the MOV can absorb in a single event. After that, they will still function but with further hits will degrade.
If the single event energy rating is far above the actual energy hits, the cumulative energy rating is far higher than the single event rating. With high ratings a plugin suppressor is not likely to fail.
--
bud--

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Cool!
And for an educational thread, thanks to one and all!
David
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On Jul 4, 8:49 pm, snipped-for-privacy@panix.com (David Combs) wrote:

While reading wikipedia's discussion on MOVs, well, where does that surge energy get dissipated? That is what MOVs (like zener diodes, gas discharge tubes, etc) do. None protect by absorbing surge energy. If so, then all would explode. Each works by - as NIST says -

From a 1 Jan 2007 discussion entitled "Acceptable Lightning Ground?" in rec.radio.amateur.antenna :

"Planning guide for Sun Server room" from Sun Microsystems:

Surge energy must be diverted to where energy gets dissipated harmlessly. Some will confuse energy 'absorbed' by an MOV as the protection. However as MOV joules increase, then energy absorbed by that MOV decreases. That's what we want. More energy diverted into earth. Less energy absorbed by the protector. A protector does not provide protection. What absorbs (dissipates) a surge provides protection - earth ground.
Protection is about dissipating surge energy without damage. A short connection to earth. Diverting surge energy is what avalanche (zener) diodes, MOVs, and GDTs do, as even the Wikipedia source would note.
Furthermore, it is not just any earth ground. All incoming utilities must connect 'short' to the same "single point earth ground". How to correct an installation mistake is demonstrated by a utility: http://www.cinergy.com/surge/ttip08.htm Another industry professional demonstrates that every incoming utility (including underground) wire must be earthed (directly or via a protector) in "The Need for Coordinated Protection" http://www.erico.com/public/library/fep/technotes/tncr002.pdf
MOVs that diverts a surge must be sufficiently large so as to not fail catastrophically or trip that failure indicator light. MOVs must be sized so that even a direct lightning strike is earthed and MOVs remain functional. As many have observed, plug-in protectors manufactured for profit rather than protection have a history of failure indicated by that lamp. That lamp says protector circuits were grossly undersized - was ineffective proetction.
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Wow, the amount of misinformation and misapplied information here is amazing and all the apples and oranges compaisons make it even more so.
A direct lightning strike can not be "earthed" for the expected duration of most lightning strikes. No component yet known to man will withstand a direct lightning strike. Protection is not sold to protect agains direct lightning strikes - ever. Don't let the advertising hype and phoney warranties fool you.
There is a lot more to surge protection than the path to earth. In fact, most often the actual path to earth is irrelevant: What IS relevant is the path of the surge AROUND the equipment being protected; the protection components are by definition sacrificial and there is no way around it.. Earth protection is going to do nothing for a surge that sends the hot line thousands of volts in one direction and the neutral likewise in the other direction. Neutral is NOT earth to surges of the magnitudes discussed here. Whole House protection is indeed worthwhile, and a good idea, but ... it does not for instance mean that you don't still need protection for your computer. There are plenty of surges and spikes generated IN your home every time a motor starts, changes speeds, or a relay throws, a switch is activated, and on and on. They can be very substantial. That, on top of the spikes and surges that make it through the power xfmr is why even with whole house protection, one should still have protection on their more expensive components; computers, electronic sewing machines, refrigerators, microwaves, etc. etc.. Microwaves in fact are another substantial source of spikes when that klystron kicks on and off, just as are many makes of laser printers. And etc.. Besides, a UPS is still much better; it's fast, disconnects the mains, and lets the computer or whatever it's protecting be powered down gracefully in any situation from a brownout to loss of grid.
Get real, people; either quite guessing and surmising or get off the topic. I think I only saw two people in this thread seemed to actually know what they were talking about. The rest of it's crap of the highest quality as crap goes.
HTC
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TWayne wrote:

. Comments do not involve a direct lightning strike to a house. For that protection you need lightning rods.
Francois Martzloff was the surge guru at the NIST. He wrote numerous published technical papers on surges an surge protection. He is an expert in the field.
------------------------- One of Martzloffs papers looked at a 100,000A lightning strike to a utility pole behind a house in typical urban distribution. It is calculated that on average a worse event would happen once in 8,000 years (more often in central Florida, less often in Nevada).
Of the 100,000A, 30,000A went toward the house on the neutral. The energy on the neutral was directly earthed by the N/G/earth-electrode bond required in US services. Some of the energy is inductively and capacitively coupled to the hot service wires. I believe Martzloffs paper is the basis for the (IEEE standard) maximum likely surge on hot power lines of 10,000A
Service panel suppressors with ratings over 10,000A are readily available.
Martzloffs paper should still be available on the internet if you want to read it.
------------------------ Another Martzloff technical paper looked at a MOV at the end of 30 ft and longer branch circuits with 2,000-10,000A surges and no suppressor in the service panel. (Compare 10,000A with the max likely 10,000A above.) The maximum energy dissipated in the MOV was 35 Joules. In 13 of 15 cases it was 1 Joule or less.
It should be noted that neither service panel or plug-in suppressors protect by absorbing energy, but they absorb some energy in the process of protecting.
One of the reasons energy at the MOV is so low is that at about 6,000V there is arc-over (US) from hot bus to panel/neutral/system-ground/earthing-electrode. After the arc starts the voltage falls to hundreds of volts across the arc. That dumps most of the surge energy to earth.
Maximum Joule dissipation was for the short branch circuit and surprisingly the lower current surges below 5,000A. The reason is that the MOV was able to clamp the voltage at the panel and hold the voltage below 6,000V required for arc-over. Receptacles also arc-over at about 6,000V
As I wrote elsewhere, I recently bought a major brand plug-in suppressor with ratings of 590J and 30,000A per MOV, 1770J and 90,000A. Compare to 35J on a severe surge.
Martzloffs paper should still be available on the internet if you want to read it.
---------------------------- Martzloff has also written "In fact, the major cause of [surge suppressor] failures is a temporary overvoltage, rather than an unusually large surge."
Source should still be available if you want to read it.
----------------------------- The NIST guide, written by Martzloff and referenced elsewhere, cites US insurance information that says the most commonly damaged equipment is computers (with modem) and TV (presumably with cable). All can be damaged by high voltage between power and signal wires. The IEEE (starting pdf page 40) guide has an illustration of a surge coming in on a cable service resulting in 8,000V between power and cable wires. The guide also shows using a plug-in suppressor to protect the TV.
All interconnected equipment has to be connected to the same plugin suppressor and external wires, like phone and cable, have to go through the suppressor.
---------------------------- From Martzloffs research (and other sources) I see no reason why a properly connected service panel suppressor or plug-in suppressor cant protect against about any lightning surge.
I eagerly await your sources that say service panel and plug-in suppressors can not protect against lightning (other than direct strikes to the house). .

. A great deal of the protection is keeping the ground references for power and phone and cable at the same voltage. That requires *short* ground wires from phone and cable entry protectors to the earthing wire at the power service.
Keeping the ground references for power, cable, and phone together is a major part of how plug-in suppressors work. .

. A UPS will let the protect equipment power down gracefully. But they cant disconnect fast enough to protect against a surge. A lightning induced surge might be over in 80 microseconds. .

. Perhaps you could provide sources that support your opinions. I can find you a source for most of what I have written in this thread.
--
bud--

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wrote Re Re: Whole house phoneline surge protection:

So, given the above would a surge suppressor like this
http://www.apc.com/resource/include/techspec_index.cfm?base_sku=PRO7T
provide any worthwhile protection to the phone line and computer plugged into it?
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Caesar Romano wrote:

Sure.
For your amusement the UL listings are: UL497A telephone surge protector UL1283 EMI filters UL1363 outlet strip UL1449 surge suppressor
For surge suppression the significant ones are UL497A and 1449. UL listing means the suppressor is at least above a floor (and can be way above).
As I have said previously, personally I like to have high Joule (or equivalent surge current) ratings, but I may go to extremes. The 2 that I am using have total device ratings of 1770 and 2600J. Both have connected equipment warrantees. They cost about $30.
What you use depends at least partly on the risk. Live in central Florida? Very short branch circuit wire to service panel?
At the risk of being repetitious - all interconnected equipment needs to be connected to the same plug-in suppressor. All external wires (cable, phone, ...) need to go through the suppressor.
--
bud--

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Notice that the APC does not list each type of surge and protection from that surge. Francois Martzloff defined the problem in the first conclusion of his 1995 IEEE paper:

Bud will selectively quote sentences from that paper trying to dispel the bottom line. Without a dedicated connection to earth ground, that APC does not provide effective protection. Without that earthing connection, then where does surge energy get dissipated? Therefore APC cannot claim protection from each type surge in specifications.
UL numbers say nothing about effective protection. For example, UL1449. When the surge test occurs, a protector can completely fail - provide zero protection - and still get UL1449 approval. Why? UL says nothing about the appliance (or power strip) working. UL standards only address your safety. None of those UL specs state anything about protection. A UL1449 protector can completely fail during testing. But if it does not spit flame during that testing, then it can be UL registered.
Most every fire company has at one time seen this problem even with UL1449 approved protectors. Even a fire marshal describes why UL1449 approved protectors still create a fire hazard. Scary pictures: http://www.hanford.gov/rl/?pageU6&parentU4 http://www.westwhitelandfire.com/Articles/Surge%20Protectors.pdf http://www.ddxg.net/old/surge_protectors.htm http://www.zerosurge.com/HTML/movs.html http://tinyurl.com/3x73ol http://www3.cw56.com/news/articles/local/BO63312 /
Did you know your telco installs and earths a 'whole house' protector on your phone line? Protection that is required. A superior and effective protector installed for free, in part, because 'whole house' protectors accomplish so much and cost less money. You need one 'whole house' protector for AC mains that will cost about $1 per protected appliance. Even if using plug-in protectors, that 'whole house' protector with proper earthing is still necessary. A protector is only as effective as its earth ground. Even Martzloff notes a problem created by unearthed protectors during a type of surge that is typically destructive.
Plug-in protector is for a type of surge made irrelevant by protection already inside computers.
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