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w_tom wrote:
.


. Still never answered - how common mode power surges get past the N-G bond in US power services. .

. Apparently w_ cant google because the institution only lets w_ look at newsgroups - the internet has dirty pictures. .

. The example in the IEEE guide starting pdf page 40 is a common mode surge on a cable drop. The illustration shows how a plug-in suppressor provides protection. Because of his religious blinders, poor w_ cant understand the simple explanation and has to reinterpret what the IEEE guide says. .

. From the IEEE guide. Surge comes in on cable drop. 2TVs. Plug-in suppressor at TV1 protects it. Voltage at TV2 (cable to power) goes from 10kV to 8kV.
Repeating: 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."
Repeating: w_ says suppressors must only be at the service panel. In this example a service panel protector would provide absolutely *NO* protection. The problem is the wire connecting the cable entry block to the power service ground 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."
Because it violates his religious belief in earthing, w_ frequently lies about what this illustration shows. .

. Explained often and ignored because of religious blinders.
Repeating: The guide explains earthing occurs elsewhere.
Repeating: If w_ could read he would find in the IEEE guide example (pdf pg 40) that "the vast majority of the incoming lightning surge current flows through" the ground wire from the cable ground block to the power service. And the guide says that is "as the NEC/CEC writers intended." The surge is earthed. But not primarily through the plug-in suppressor.
.

. Hundreds of posts? w_ exaggerates 1E6 times.
Specs provided and ignored. There are some in my other post. .

. Look at a surge coming in on power wires to the service panel. If you earth a relatively modest 1000A surge through a very good 10 ohm impedance to earth, the ground at the service panel rises 10,000V above absolute ground potential. Equipment connected only to power can float above absolute ground. The only way to protect equipment with phone/cable connection is to make sure the phone and cable ground potential is the same as the power ground. That requires a short connection from entrance protectors to the power system ground. That is called a single point ground.
Plug-in suppressors do the same thing except earthing does not occur primarily through the suppressor. The IEEE guide explains earthing occurs elsewhere. A plug-in suppressor is a local single point ground. Since earthing is not involved at the suppressor poor w_ cant understand. .

. Martzloff says "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." [But remember that Martzloff has a hidden agenda.] .

. And the required statement of religious belief in earthing. Never fly in a airplane - they arent earthed at all and have no lightning protection.
Everyone agrees earthing is a good idea. The only question is whether plug-in suppressors work. Both the IEEE and NIST guides says plug-in suppressors are effective.
w_ still has not found another lunatic that says plug-in suppressors are NOT effective. Why doesnt anyone agree with you w_?
w_ has still never answered simple questions: - Why do the only 2 examples of protection in the IEEE guide use plug-in suppressors? - Why does the NIST guide says plug-in suppressors are "the easiest solution"? - How would a service panel suppressor provide any protection in the IEEE example, pdf page 42?
Bizarre claim - plug-in surge suppressors don't work Never any sources that say plug-in suppressors are NOT effective. Twists opposing sources to say the opposite of what they really say. Invents opinions and attributes them to opponents. Attempts to discredit opponents. w_ is a purveyor of junk science.
--
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| w_tom wrote:
| . |>> The comments questioned above were only whether a common mode surge |>> coming in on power wires can get past the N-G bond in US services. And |>> it is a side issue because plug-in suppressors will protect from both |>> common and transverse mode surges. | . | Still never answered - how common mode power surges get past the N-G | bond in US power services.
Maybe you should ask in sci.physics. I do remember explaining this once before, but I don't know if it was in this subthread or another. I will try again, and this time the post will be nothing more than this to be sure it doesn't get lost in the mix of includes and rebuttals that most posts in this and many other threads tend to have.
The leading edge of a surge propogates at a significant fraction of the speed of light along a wire. When that wire splits apart, the edge propogates over both of those wires. Unless those two wires together have the same characteristic impedance as the wire the edge arrives on, there will also be a backward reflection of that edge along the same wire it arrived on. The proportions of energy going over each wire from that point vary according to the characteristic impedance.
The N-G bond is one of those "wires". The continuation of the neutral is another. The surge edge impulse will this go its way over both of those paths, dividing the energy between them (and likely also some to the reflection back up the service drop N/G combination wire).
The fact that the N-G bond is a usable short path to ground does not affect the division of impulse energy.
If the grounding electrode connection(s) are attached directly at this point of bonding, the electrical energy will propogate in all of these directions. This includes the grounding wire of the various circuits fed from the panel the N-G bond is in. In other words, the surge that came in on the service neutral will propogate over the neutral of the branch circuits, the ground of the branch circuits, and the conductors that attach to the grounding electrodes.
The energy in the neutral and ground wires of the branch circuits will now be lower. But it will not be zero. The energy in the hot wire may be reduced as well, depending on how it branches out and around. But there will be some energy level remaining on hot, neutral, and ground.
This then makes up a mixed mode surge. Some of the energy is common mode. What is different between any pair of wires being considered is the differential or traversal mode.
The (or rather, a significant part of) energy of the surge gets past the N-G bond to the neutral bus and to the branch circuit neutral wires simply because they are connected.
The surge energy is NOT caused by any means to entirely divert over the N-G bond to the ground bus, and to only the grounding electrode wires, just because they happen to be earthed.
The path selection the energy impulse takes at a point of multiple paths is in inverse proportion to the square of the instantaneous characteristic impedance. If you want to have zero surge going over the neutral wire, then you need to make it have a (nearly) infinitely high impedance. In other words, disconnect the neutral before the surge arrives.
All of the above pertains to the surge IMPULSE. The behaviour of an impulse is quite different than the behaviour of DC or low frequency AC. In the latter case, the CHANGE of voltage will still propogate just like an impulse, but the impulse will return, effectively cancelling out most of the current that is associated with it. The slight difference is the charging current of the circuit (quite small in home wiring). The change in voltage when you flip on a switch is quite small relative to short time frames like a microsecond. But a lightning surge can have very large voltage changes in that same time frame, especially if it is a direct strike (as opposed to just an induced surge from a nearby strike).
The N-G bond serves many purposes well. But for high transient voltage surges, it only marginally reduces the surge (the amount diverted away to ground).
A well designed surge suppressor will design the various connections in a way that will have a LOW characteristic impedance at the frequencies the high transient impulse represents for the path to the grounding electrodes, and a HIGH characteristic impedance at these same frequencies for the path to the protected electrical circuits. It will do this on all conductors, not just the neutral. It has to do the opposite for the low AC frequency of the power service, aside from the neutral to earth connection which can be low impedance at all frequencies. An arc gap might be used between the hot conductors and that ground path, to be a low impedance above breakdown voltages.
--
|---------------------------------------/----------------------------------|
| Phil Howard KA9WGN (ka9wgn.ham.org) / Do not send to the address below |
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snipped-for-privacy@ipal.net wrote:

. Martzloff et al. looked at whether you have to model a branch circuit as a transmission line. You don't. But Martzloff had a hidden agenda.
Too bad none of the 6 EE authors of the guides are as smart as you. Maybe you should publish a paper.
--
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| snipped-for-privacy@ipal.net wrote:
|> |> | w_tom wrote:
|> | . |> |>> The comments questioned above were only whether a common mode surge |> |>> coming in on power wires can get past the N-G bond in US services. And |> |>> it is a side issue because plug-in suppressors will protect from both |> |>> common and transverse mode surges. |> | . |> | Still never answered - how common mode power surges get past the N-G |> | bond in US power services. |> |> The leading edge of a surge propogates at a significant fraction of the |> speed of light along a wire. When that wire splits apart, the edge |> propogates over both of those wires. Unless those two wires together |> have the same characteristic impedance as the wire the edge arrives on, |> there will also be a backward reflection of that edge along the same |> wire it arrived on. The proportions of energy going over each wire from |> that point vary according to the characteristic impedance. | . | Martzloff et al. looked at whether you have to model a branch circuit as | a transmission line. You don't. But Martzloff had a hidden agenda. | | Too bad none of the 6 EE authors of the guides are as smart as you. | Maybe you should publish a paper.
But at least now you know how the surge can get past the N-G bond. So you don't have to ask anyone else that question, anymore.
--
|---------------------------------------/----------------------------------|
| Phil Howard KA9WGN (ka9wgn.ham.org) / Do not send to the address below |
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snipped-for-privacy@ipal.net wrote:

. No. I know you can misapply theory to predict a result that doesnt happen in the real world.
You appear to be educated beyond your intelligence.
--
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bud-- wrote:

Many times over. :(
--
Service to my country? Been there, Done that, and I've got my DD214 to
prove it.
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IEEE authors routinely noted the problem with what Bud posts. Bud will cite selectively what Martzloff wrote. Bud will claim plug-in protectors need no earth ground.
Bud will not post what Martzloff also says - bluntly. A plug-in protector without proper earthing can earth a surge destructively through household appliances. How curious. This engineer has seen same even many decades ago. And Bud's citation - Page 42 Figure 8 - says the same thing - contradicts Bud. What does Martzloff say and what does Bud ignore to promote plug-in (point of use) protectors?

Plug-in protector without that so critical 'less than 10 foot' connection to earth can, instead, earth a surge, 8000 volts destructively, through TV2. This also from a Bud citation on Page 42 Figure 8.
Effective protection earths surges where all wires enter the building. This same solution is why telco COs suffer maybe 100 surges in every thunderstorm - and no damage. Those same telcos avoid everything Bud has recommended. Effective protectors make that 'less than 10 foot' connection. We call the effective protector (from responsible manufacturers) a 'whole house' protector. Only one is required on each incoming wire. Some of those responsible manufacturers are Intermatic, Square D, Leviton, Cutlet-Hammer, Keison, Polyphaser, Siemens, and GE. Who is not on that list? Belkin, APC, and Tripplite. Why? Where is that dedicated wire to earth ground? No earth ground means no effective protection.. Somehow Bud's protectors use magic to absorb what three miles of sky could not stop?
One need not remember these names. A responsible homeowner simply examines the protector. Will it make a 'less than 10 foot' connection to single point earth ground? If not, it is probably a grossly overpriced, ineffective protector promoted by Bud.
A protector is only as effective as its earth ground. All this being irrelevant to the OP's question.
One 'whole house' protector properly earthed means surges cannot explain electronics failure inside that dryer. Internal electronics failures best understood by an autopsy of that 'dead body'.
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w_tom wrote:
.

. Cite selectively? w_ forgets to mention that Martzloff wrote in the same document: "Mitigation of the threat can take many forms. One solution. illustrated in this paper, is the insertion of a properly designed surge reference equalizer [multiport plug-in surge suppressor]."
At the time of the paper, 1994, multiport suppressors were just a concept or very new. In 2001 Martzloff wrote the NIST guide which also says plug-in suppressors are effective.
Because plug-in suppressors violate w_'s religious belief in earthing he has to twist what Martzloff (and everyone else) says. .

. And another repetition of the lie. .

. Martzloff wrote a guide for customer service reps for rural electrical coops including: "Whole house protection consists of a protective device at the service entrance complemented by [plug-in surge suppressors] for sensitive [electronic equipment] within the house." .

. The required statements of religious belief in earthing.
w_'s religious blinders only let him see what agrees with his religious view. Everything else is invisible. w_ is the poster child for cognitive dissonance.
--
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Martzloff says what is necessary to make a protector effective. Earth ground. Why does Bud forget to mention that part? Bud also forgets what Martzloff also says. A plug-in protector may even be harmful to adjacent appliances. How curious. We saw the exact same thing when a plug-in protector earthed surges destructively through a network of powered off computers. Page 42 Figure 8 demonstrates the same problem.
Bud ignores what is written in Martzloff's very first conclusion. The plug-in (point of use) protector can even contribute to appliance damage:

Why would Bud ignore what Martzloff says? Profits are at risk. Bud must post selectively. Every source says the protector will only be as effective as its earth ground.
Bud says a protector works by 'clamping to nothing'. Professionals say that clamping (shunt) must be short to single point earth ground.
Bud says a protector works by making surge energy magically disappear. Professionals say that energy must be dissipated in earth.
Bud says that a MOV connecting two wires together makes the common mode voltage disappear. Professionals say that will leave both wires at the same thousands of volts - a voltage that can be reduced only by connecting it short to earth ground.
Bud says a protector is connected to earth by neutral and safety ground wire. Professional (such as both front page articles in EE Times) state that wire to earth ground must be short (ie 'less than 10 feet'), have no sharp bends, no splices, separated from other wires, etc. Provided previously were voltages when the wall receptacle is 50 feet from the breaker box. Something less than 12,000 volts when the surge is a trivial 100 amps. 12,000 volts is protection? No wonder professional cite Page 42 Figure 8 - the surge earthed 8000 volts destructively through an adjacent TV.
Why does Bud forget these other facts from professionals? Take a $3 power strip. Add some $0.10 parts. Sell it for $25 or $150. Profits are at risk when the consumer learns "A protector is only as effective as its earth ground". Consumer might learn that one 'whole house' protector from responsible manufacturers provides significantly superior protection for tens or maybe 100 times less money.
A short list of facts that Bud must avoid to promote plug-in protectors. So where is that manufacturer specification that claims protection from each type of surge? Bud says the plug-in protector is complete protection. The manufacturer will not even make that claim. Bud never provides a single manufacturer spec that claims protection. Bud cannot cite what does not exist. So Bud posts insults.
Honesty is not Bud. Profits would be at risk. Where is that manufacturer spec? Crickets.
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| Martzloff says what is necessary to make a protector effective. | Earth ground. Why does Bud forget to mention that part? Bud also
For surge energy components that are low in frequency, earth serves as the "sink". It's the other end of the difference between earth and sky.
For surge energy components that are high in frequency (e.g. the leading edge of the transient rising voltage), if they make it to earth, it will have more places to go instead of reflecting back.
| forgets what Martzloff also says. A plug-in protector may even be | harmful to adjacent appliances. How curious. We saw the exact same
To the extent that a surge on hot or neutral jumps over to ground in a surge protector at the appliance location, that means the ground wire has the surge. If the 2nd appliance is on the same branch, it now gets another surge.
But it would get the first surge on the hot wire, too, right? Maybe. Maybe not. Maybe it was switched off in such a way that such a surge would be well attenuated.
| Why would Bud ignore what Martzloff says? Profits are at risk. Bud | must post selectively. Every source says the protector will only be | as effective as its earth ground. | | Bud says a protector works by 'clamping to nothing'. Professionals | say that clamping (shunt) must be short to single point earth ground.
A protector can provide additional paths to "spread out" the surge even if it isn't connect to earth. That may be a good thing in some cases (none of the paths have anything to damage) or a bad thing in other cases (more things can be damaged if the now weaker split up surge is still strong enough to do damage).
| Bud says a protector works by making surge energy magically | disappear. Professionals say that energy must be dissipated in earth.
Maybe ths surge is floating away with the magic smoke? :-)
| Bud says that a MOV connecting two wires together makes the common | mode voltage disappear. Professionals say that will leave both wires | at the same thousands of volts - a voltage that can be reduced only by | connecting it short to earth ground. | | Bud says a protector is connected to earth by neutral and safety | ground wire. Professional (such as both front page articles in EE | Times) state that wire to earth ground must be short (ie 'less than 10 | feet'), have no sharp bends, no splices, separated from other wires,
E.g. must have very little inductance and other impedances for high frequency transients.
| etc. Provided previously were voltages when the wall receptacle is 50 | feet from the breaker box. Something less than 12,000 volts when the | surge is a trivial 100 amps. 12,000 volts is protection? No wonder | professional cite Page 42 Figure 8 - the surge earthed 8000 volts | destructively through an adjacent TV. | | Why does Bud forget these other facts from professionals? Take a $3 | power strip. Add some $0.10 parts. Sell it for $25 or $150. Profits | are at risk when the consumer learns "A protector is only as | effective as its earth ground". Consumer might learn that one 'whole | house' protector from responsible manufacturers provides significantly | superior protection for tens or maybe 100 times less money.
A plug-in (a power strip type being the typical example) does provide supplementary protection from a variety of surge classes. It just does not do as good a job as an entry protector with a ground connection. But even the latter is not 100% protection. Nothing is 100% protection. Doing both is the maximum protection that is practical in most cases.
--
|---------------------------------------/----------------------------------|
| Phil Howard KA9WGN (ka9wgn.ham.org) / Do not send to the address below |
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w_tom wrote:

. Intelligence is not w_.
Just the same drivel - *all* debunked.
Still *no* link to another lunatic that says plug-in suppressors are NOT effective. You cant find anyone who agrees even on the internet???
Still *no* answers to simple questions: - Why do the only 2 examples of protection in the IEEE guide use plug-in suppressors? - Why does the NIST guide says plug-in suppressors are "the easiest solution"? - How would a service panel suppressor provide any protection in the IEEE example, pdf page 42? How come you dont answer simple questions w_???
Bizarre claim - plug-in surge suppressors don't work. Never any sources that say plug-in suppressors are NOT effective. Twists opposing sources to say the opposite of what they really say. Invents opinions and attributes them to opponents. Attempts to discredit opponents. w_ is a purveyor of junk science.
For real science read the IEEE and NIST guides. Both say plug-in suppressors are effective.
--
bud--

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Look at the three citations from Bud. Bud says a plug-in protector will make all types of surges somehow disappear. Bud's IEEE citation shows how a plug-in protector might work. Then shows why the plug-in protector - too close to appliances and too far from earth ground - will even earth a surge 8000 volts destructively through adjacent appliances. Page 42 Figure 8. That energy must be dissipated somewhere. Bud calls that 8000 volt damaged TV "effective protection".
Bud claims a protector needs no earthing to magically stop what even three miles of sky could not stop. But Bud's NIST citation repeatedly says different. On page 6 (Adobe page 8 of 24) at:

On page 17 (Adobe page 19 of 24):

Best protection can be useless if grounding is not done properly. But Bud says a protector works by 'clamping to nothing'? Why does Bud's citation contradict Bud?
And finally Bud makes some claim that Martzloff recommends plug-in protectors. But Martzloff says the plug-in (point of use) protector can even harm appliances:

Why do each source contradict what Bud says? Maybe Bud could provide a manufacturer spec that claims protection? No, Bud cannot even do that. Plug-in protectors do not even claim to provide Bud's 'magic box' protection from type of surge that typically causes damage. Why does Bud forget to admit this?
Spend tens or maybe 100 times more money for Bud's ineffective protectors. Or install (earth) what all locations that cannot suffer any damage must do. Why do telco COs not use what Bud recommends? They suffer maybe 100 surges during every thunderstorm. They cannot waste money on protectors that are ineffective. Instead, telcos earth every incoming wire at the service entrance. How curious. The one solution for massive protection is sold by people Bud does not promote. GE, Siemens, Square D, Cutler-Hammer, Keison, Leviton, Intermatic, or Polyphaser all sell protectors that make that earthing connection.
How do we know these manufacturers make effective protectors? The effective protector has a dedicated wire for that 'less than 10 foot' earth ground. What happens when the connection to earth is longer? More of the surge seeks earth ground destructively inside the building. Shorter earthing connections mean even better protection. Bud says no earthing is needed for protection.
All appliances contain significant protection. Protection that can be compromised by an adjacent protector. Protection that can be overwhelmed if the typically destructive surge is not earthed where wires enter the building.
Bud distorts what the IEEE, NIST and Martzloff say. Profits are at risk. Responsible sources even say why an effective protector makes that short, low impedance connection to earth (as demonstrated in both front page articles from EE Times). Bud's citations even contradict Bud.
A protector is only as effective as its earth ground. As the NIST says bluntly, the function of a protector is to "simply divert it to ground, where it can do no harm." A direct quote that Bud must deny. NIST could not be more honest. Did we mention those 'scary pictures' created by undersized plug-in protectors that Bud recommends?
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w_tom wrote:
.

. w_'s religious blinders don't let him see what the IEEE, NIST and Martzloff say.
w_ still has never answered simple questions: - Why do the only 2 examples of protection in the IEEE guide use plug-in suppressors? - Why does the NIST guide says plug-in suppressors are "the easiest solution"? - Why did Martzloff say in his paper "One solution. illustrated in this paper, is the insertion of a properly designed surge reference equalizer [multiport plug-in surge suppressor]." - How would a service panel suppressor provide any protection in the IEEE example, pdf page 42? Where are you answers w_???
And where is a link to another lunatic that says plug-in suppressors are NOT effective. You can't find anyone who agrees even on the internet???
Bizarre claim - plug-in surge suppressors don't work. Never any sources that say plug-in suppressors are NOT effective. Twists opposing sources to say the opposite of what they really say. Invents opinions and attributes them to opponents. Attempts to discredit opponents. w_ is a purveyor of junk science.
For real science read the IEEE and NIST guides. Both say plug-in suppressors are effective.
--
bud--

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Again Bud 'cut and pastes' his diatribe while his citations say otherwise. Where is that manufacturer spec that claims any protection? Bud cannot define protection when plug-in protector manufacturers will not make that claim in writing. How are they effective? Take a $3 power strip. Add some $0.10 parts. Sell it for $25 or $150. "Plug-in suppressors are effective" at enriching the manufacturer.
When grossly undersized to fail due during a surge, well, failure is also effective for improving the bottom line. And that failure gets the naive to effectively recommend more plug-in protectors.
Profits are at risk. So again, Bud posts his myths incessantly. Where are those spec numbers that claim protection? Bud cannot post spec numbers that do not exist. So Bud even pretends that Page 42 Figure 8 does not exist: a plug-in protector earthing a surge 8000 volts destructively through the adjacent appliance.
Of course Bud will reply again. Bud repeatedly posts same insults and myths to get the last word. Bud never posted a single spec that claims plug-in protection. Bud cannot post numbers that never existed.
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w_tom wrote:
.

. Being evangelical in his belief in earthing, w_ trolls google-groups for "surge" to paste in his religious tract to convert the heathens. That is how he arrived here. He continues to cut and paste his religious tract because his religious belief in earthing has been challenged. .

. Of course I did. And I already told you twice that I already told you.
w_ just posts the same lies - a la Goebbels.
w_ still has never posted a link to another lunatic that says plug-in suppressors are NOT effective.
w_ still has never answered simple questions: - Why do the only 2 examples of protection in the IEEE guide use plug-in suppressors? - Why does the NIST guide says plug-in suppressors are "the easiest solution"? - Why did Martzloff say in his paper "One solution. illustrated in this paper, is the insertion of a properly designed surge reference equalizer [multiport plug-in surge suppressor]." - How would a service panel suppressor provide any protection in the IEEE example, pdf page 42?
Bizarre claim - plug-in surge suppressors don't work. Never any sources that say plug-in suppressors are NOT effective. Twists opposing sources to say the opposite of what they really say. Invents opinions and attributes them to opponents. Attempts to discredit opponents. w_ is a purveyor of junk science.
For real science read the IEEE and NIST guides. Both say plug-in suppressors are effective.
--
bud--

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| The comments questioned above were only whether a common mode surge | coming in on power wires can get past the N-G bond in US services. And | it is a side issue because plug?in suppressors will protect from both | common and transverse mode surges.
I see a possible point of confusion here. The term "plug-in suppressor" has TWO different applicable devices that different people might associate with this term:
1. A power strip type surge protector that plugs into the outlet (and appliances are plugged into it). Some have connections for other things like 75 ohm coax on F connectors, RJ-11 connectors for phone lines, and maybe even RJ-45 for LANs (haven't see that, yet, but I can't rule it out).
2. A surge protection module that plugs into breaker panel or into a special type of receptacle (common in hospitals, but maybe they are showing up in more areas, now). The more common one is a module that plugs into the space of 2, 4 or 8 breakers in a common plug-in breaker style panel.
Type #1 has no means to protect against a common mode surge that arrives on all THREE wires, unless it has a diversion path (usually to earth). But doing this at distance from the breaker panel creates new risks, such as elevated ground potential running backwards through the circuit.
If you think this protector can protect against a THREE wire common mode surge, do tell where you THINK the surge energy will be diverted to.
Type #2 isn't any better at protecting against common mode. But closer to the N-G bond and particularly to the grounding electrode connections, it is more likely to see a reduced surge voltage on the ground wire and thus be able to divert some energy from the hot/line wires over to the ground wire (or the neutral if it doesn't have a ground connection that is separate from the neutral ... which should only be done in the main panel that has the N-G bond).
--
|---------------------------------------/----------------------------------|
| Phil Howard KA9WGN (ka9wgn.ham.org) / Do not send to the address below |
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snipped-for-privacy@ipal.net wrote:

OK Phil, at least; unlike some other posters; your arguments are clearly written and well argued. So let me pose a question. If a common mode serge reaches a plug in Transient Voltage Surge Suppressor and that device does what it is designed to do; which if I understood my previous training correctly is to keep the voltage as near to the same on all three wires as possible; isn't that effective protection. No voltage difference would mean no current flow. No Current flow equals no power delivered to the protected load. No power equals no damage. Objective achieved, declare victory, and go home.
I have done remote installs from Alaska to Argentina to Arizona and in the real world work we did single point grounds and listed TVSS installs kept the equipment functioning month after month and year after year. When these sites failed we got phone calls and lots of them. The Alaska site had a vent control failure that caused the batteries to fail explosively and a colleague was en route to the site before the acid stopped fuming. The Arizona site had a physical failure of the structure years after I left the company that manufactured it. I still got a phone call. So far not one call for a lightning or surge caused failure. To what do we owe our clean record of power system survivability in lightning prone environments. Meir careful adherence to the IEEE and NIST guidance on protection that some on this newsgroup keep trying to dismiss as ineffective would be my answer. But I'm sure some would say that since it violates their belief that low impedance earthing is the only answer it's just dumb luck.
--
Tom Horne

"This alternating current stuff is just a fad. It is much too dangerous
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| OK Phil, at least; unlike some other posters; your arguments are clearly | written and well argued. So let me pose a question. If a common mode | serge reaches a plug in Transient Voltage Surge Suppressor and that | device does what it is designed to do; which if I understood my previous | training correctly is to keep the voltage as near to the same on all | three wires as possible; isn't that effective protection. No voltage | difference would mean no current flow. No Current flow equals no power | delivered to the protected load. No power equals no damage. Objective | achieved, declare victory, and go home.
No, it is not effective protection against a common mode surge. It can still attenuate the surge in some ways, especially if the ground wire is not part of the arriving surge.
In the case of a common mode surge, there is no voltage between the leads of the MOV, so they would not conduct, assuming the leading edges arrive in sync. But there is voltage propogation, and thus a charging current.
In the case of a mix mode surge (one wire is a higher voltage than the other, but both are high in the same polarity), the MOVs still should conduct. When they do, the best they can accomplish between these two wires is to bring the voltages close together. They could change a mixed mode surge into a (nearly) pure common mode surge.
Now back to common mode. The surge will continue on to the device that was supposed to be protected. It will suddenly raise the voltage of the device as a whole. It is unlikely that the very fast rise time will make it all the way through to digital circuits in a computer, but if it did, that could be destructive to the very sensitive parts just because of the high voltage causing inappropriate breakdown of various barriers of the high density solid state circuitry. Still, in very quick order, the voltage rises, and has no where to go. Translate the "no where to go" to bouncing around from end point to end point of the various apparent subpaths of the device. That can include attached devices like keyboard, mouse, modem, ethernet, video, etc. Those next devices are also charged up by the surge. Some of them provide paths out to other places, such as the modem going to the phone line or cable TV connection. You can then see a high current rise on those paths as well.
When I was in college, home on break, I woke up in the night due to a thunderstorm. I had recently installed a new TV antenna to get a new UHF station, but had not put any protection on it, yet. So I went to the living room and unplugged the antenna lead coax from the TV and tossed the end into the middle of the room. I went back to bed and heard the storm pass. Later on in the morning another storm line came through. During it I heard a very loud lightning hit and my mother who was already up and in the kitchen screamed. I got up to see what had happened. The antenna took what might have been a direct hit. The carpet around the end of that antenna lead was charred about 20 cm radius (not an exactly uniform circle). Nothing else was damaged. The coax lead was fine. The antenna was fine. The TV was fine. I was able to watch the new TV station without the need to replace anything. Insurance covered most of the carpet replacement. I got stuck paying the difference since it was my antenna.
At the end of that coax, the voltage gradient rose very high. At least a lot of the energy from the surge dissipated into the air in some way. I wasn't there so I could not see how wide the flash really was. My mother did say she saw a bright flash, but thought it was just from the lightning as seen through the windows. But it was very very hot for at least a little distance from the end of the coax and apparently not anywhere else.
| I have done remote installs from Alaska to Argentina to Arizona and in | the real world work we did single point grounds and listed TVSS installs | kept the equipment functioning month after month and year after year. | When these sites failed we got phone calls and lots of them. The Alaska | site had a vent control failure that caused the batteries to fail | explosively and a colleague was en route to the site before the acid | stopped fuming. The Arizona site had a physical failure of the | structure years after I left the company that manufactured it. I still | got a phone call. So far not one call for a lightning or surge caused | failure. To what do we owe our clean record of power system | survivability in lightning prone environments. Meir careful adherence | to the IEEE and NIST guidance on protection that some on this newsgroup | keep trying to dismiss as ineffective would be my answer. But I'm sure | some would say that since it violates their belief that low impedance | earthing is the only answer it's just dumb luck.
The guidelines are most certainly not ineffective. To a great degree I believe that a clean and careful installation contributes to how well the various protection methods work. To the extent that a high transient surge behaves like RF, which I believe a significant portion of the energy does, minor non-obvious details like the angles two wires bolted to the same connector have relative to each other makes a big difference in how much of that high transient energy can go from one to another. Other factors can come into play in various installations, some more than others, such as common mode surges being induced from one circuit to another.
One element of protection that I think helps is added inductance following any MOVs. Cheap power strips don't have it. Some, like the Tripp-Lite isobar series, do. It's there more for isolation purposes between different plugged in devices. But it would have the effect of making the path to the protected device appearing to a fast rise transient as high impedance, and letting the (now conducting) MOV be the low impedance path, at least for differential/tranversal surge modes. But even for a common mode surge, it can help attenuate the surge fast rise component. What gets through would be much less like RF in behaviour.
I'm going to be putting up a new TV antenna, soon, to get digital TV from Pittsburgh, since the local cable TV decided not to make HD free in the basic package. This is a different house than the previous antenna. This one will get protection before it gets wired into the house. In addition to the lightning arrestor device located outside at the base of the mast, I will be putting in an additional protection of my own design. This will consist of a 4 foot long PVC pipe, stuffed with steel wool plus a copper drain conductor running through the PVC pipe in contact with the steel wool. The coax will run though the middle of that steel wool. After the pass through the steel wool, it will then wrap a few times through a large ferrite core. All this will be buried in the ground and the copper wire grounded (maybe cadwelded) via an electrode at each end of that PVC pipe (capped on each end). The idea of this is to dissipate the magnetic field of a common mode surge going over the coax. I would not do this kind of thing on power wires (they could prematurely "dissipate" the steel wool). But for TV coax, it should be OK. I don't know how effective it really will be. I won't skip any other protection just because I put that thing on there. I'll still disconnect during storms or times away from home (why I change the TV coax connections to BNC, even if it is an impedance mismatch).
Gun safety courses teach multiple methods of gun handling safety with the intent that every one of them always be practiced. It isn't about being paranoid; it's about the value of what is being protected by these methods. Lightning risk might not be quite the same thing. But in my view, it is just being wise, not paranoid, to use as many different forms of protection as is practical.
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| Phil Howard KA9WGN (ka9wgn.ham.org) / Do not send to the address below |
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snipped-for-privacy@ipal.net wrote:

. The stuff the enginers wrot missed that entirely. You proved that guy that wrot the NIST stuff had a hiden agenda, but geez - them 5 enginers that wrote the IEEE stuff are sure stupid. Probly had a hiden agenda too. An they were in the IEEE part that is suposed to be expert with surges. An they even had other pointy heded IEEE guys look at the stuff. The IEEE is just a club of intelectul loosers. I bet you arent one. And they aimed ther stuff at enginers. Them enginers will beleve anything. . > Now back to common mode. The surge will continue on to the device that

. I bet ya dont fly in airplaines. They get hit by lightnining all the time and crash. It is a BIG coverup.
Keep up the good work phil.
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Bud again refuses to post technically. So Bud is now resorting to insults and mockery. Bud's three citations from the IEEE, NIST, and Martzloff are quoted in another post. All three contradict what Bud claims. So Bud must now insult.
What do industry professionals always install with care when surges cannot cause damage? A single point earth ground. When protection must be better, then the earth ground is enhanced. Bud tells us that earthing is not necessary for surge protection. How curious. In Orange Country Florida, emergency response facilities suffered surge damage. So they installed Bud's plug-in protectors? Of course not. To stop surge damage, they simply fixed defective earthing: http://www.psihq.com/AllCopper.htm
So Bud will insult them as well?
Typically destructive surge seeks earth ground. If not earthed before entering a building, then that surge may seek destructive paths through household appliances - Page 42 Figure 8 from a Bud citation. And "Conclusion 1" from Martzloff.
Bud says a 'magic box' will stop what three miles cannot stop. That 'magic box' will make surge energy just disappear. 'Magic boxes' that even create 'scary pictures' because they are grossly undersized? Bud says such failures do not exist.
Bud recommends spending $25 or $150 for each appliance. But effective protectors from responsible manufacturers costs about $1 per protected appliance. No wonder Bud is now resorting to insult and mockery. All he need do is post a manufacturer spec that claims protection. But again, Bud does not post what does not exist. Even those plug-in protector manufacturers will not claim to provide protection. So Bud posts mockery and insults.
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