Regarding plug-in surge suppressors - a bunch of crap. Specific comments on what you said are like arguing with a Scientologist.
The "1993" paper I furnished a link to is part of a NIST "anthology on surge protection last updated in 2005. Both NIST references are current on the NIST web site.
The IEEE document is new. It is also your link.
All 3 papers from the NIST and IEEE recommend plug-in surge suppressors. Two of these papers are overall recommendations on surge protection for the general public or people involved in surge protection. Apparently you are smarter than the NIST and IEEE.
One of the authors of the Upside Down House papers you quoted was Arshad Mansoor. An electrical engineer commented: "I found it particularly funny that he mentioned a paper by Dr. Mansoor. I can assure you that he supports the use of suge equilization type plug-in protectors. Heck, he just sits down the hall from me. LOL."
I have supplied 3 supporting references. You have supplied none. I eagerly await your link to a reputable source supporting your views.
Bud - even your own supporting reference recommends the 'whole house' solution. With every paper you cite, I repsonded with waves of other papers, testimony from engineers who actually do this work, and underlying concepts you don't want to touch: equipotential and conductivity. Your response is to pretend I provided no sources. You pretend that an industry benchmark in this technology- Polyphaser - does not even exist.
Pictures from companies that do protection always start with and center that protection system around earthing. Only plug-in manufacturers hope others will not learn why earthing is the most essential part in a protection system:
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(page 14)
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Multiple I/O port protection, Single Point Ground considerations
Planning guide for Sun Server room (page 89)
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Not even the military (ie 10th Communicati> High-current surges on the power system originating
Bud - do you read your own citati> Regarding plug-in surge suppressors - a bunch of crap. Specific comments
I am for a surge suppressor at the power service and a single point ground. The issue is ONLY whether plug-in surge suppressors are effective. I don't remember waves of your papers in this thread. I don't remember any links from you in this thread [one in a different branch which is irrelevant]. One of my links is from the IEEE. Maybe you didn't know that is an association of electical and electronic engineers. PolyPhaser is probably a good reference if you have a transmitter with a big tower that attracts lightning. If I was a ham I would be very interested.
Earthing is a good idea. The question is whether plug-in surge suppressors are effective.
Hot damn - actual links!!!
I have previously said that Ufer grounds are a lot better than ground rods. I am on record as for them. Not relevant to surge suppressors.
What do you know - a transmitter tower site. Most of us do not have a very tall lightning rod next to our houses. For those of us who don't expect to protect from a direct lighting strike a Surge Reference Equalizer will work.
Thanks for the page reference. I assume you mean pdf page 14, not document page 14. This page is about is measuring the ground resistance of a Master Ground Bar at a Telco central office. It may surprise you but few of us have a telephone switch in our basements. Not mentioned is what the MGB is used for - which is to provide a single point ground reference for wires entering the room/floor/whatever. I am in favor of single point grounds. I saw no mention of plug-in surge suppressors not being effective, although I personally wouldn't use one on a telephone switch.
Surprise, surprise - another transmitter tower site. I previously have said that single point grounds at the service are very important. From PolyPhaser: "Another is to provide some form of impulse protector for each of the equipment's Input or Output (I/O) ports. These ports are usually the ac power connection, a telephone or control line, and an antenna transmission line." That is exactly what a Surge Reference Equalizer does (but not likely inclding a transmitter antenna).
"Page not found" - not uncommon with your links.
No source link. Sorry, I want to read the original in context.
As I said earlier, I agree that a surge suppressor on the power service and a single point ground reference is a good idea. But if this is one of my sources it says plug-in surge suppressors work.
My references all say that plug-in surge suppressors are effecive; didn't you read them? One of my sources [IEEE, the best one] was originally posted by you; do you read your own citations before posting them? Another of you previous posts had a different link recommeding plug-in surge suppressors; you must have not read that one either.
The issue is ONLY whether plug-in surge suppressors are effective. My links show the IEEE and NIST recommend them. Did you see that? You constantly try to change the subject, but your links are totally irrelevant or are silent on this issue, as usual.
When it comes to 'as usuals', still not provided are references that say "plug-in surge suppressors are effecive". No reason is provided for plug-in protectors to be effective. Equipotential is only one requirements for effective protection. Equipotential alone somehow makes plug-in protectors effective? No possible.
Where concepts behind a unique type of plug-in protector is cited (multiport SRE), still the author instead recommends 'whole house' protection. Where other citations only show where a plug-in protector exist, no proof or claim that the plug-in protectors are effective. In fact, anything that a plug-in protector might do effectively is already inside the appliance.
Meanwhile other responsibile sources repeatedly cite what is necessary for protection - earthing. What does that plug-in protector not provide? Earthing. Why are other highly regarded sources such as Polyphaser not discussing plug-in protectors? Polyphaser's application notes discuss effective solutions that provide both 'equipotential' AND 'conductivity to earth'. Both are required. Plug-in protectors do not provide both which is why plug-in protector manufacturers do not discuss earthing. No earth ground means no effective protection. Provided are days worth of reading that promote effective 'whole house' techniques - both in theory and in practical experience.
To lightning, a commercial radio tower, a utility AC street wire, television antenna, telco central office, or household appliances are same. All are paths to earth that may be destructive or made trivial. Protection is about earthing. Protector - be it a Franklin lightning rod or a 'whole house' protector - is about connecting a transient short to earth ground. So much research on how to protect is performed on transmitter buildings, telephone central offices, etc - same research subjects mocked by Bud hoping the lurker will believe insults rather than technical citations.
What does a Surge Reference Equalizers paper claim?
Even after studying SREs, earthed 'whole house' protector is cited as a 'best' solution. So where does anyone make responsible claims for this SRE plug-in protector? Instead, responsible sources repeatedly cite earthing as critical to protection - even after discussing merits of SRE. What does an SRE multiport protector not provide? Earthing. Each example of effective protection lists no plug-in (point of use) protectors. Of course. Even the multiport SRE protector had no effective earthing - which explains why that paper then recommends earthed 'whole house' protection.
In a previous discussion, Bud apparently did not read an IEEE Green Book (IEEE 142) quote entitled 'Static and Lightning Protection Grounding' :
We protect by intercepting or diverting to what lightning seeks - earth ground. Where is that multiport (plug-in protector) solution even mentioned? With no effective earthing, then how then can a plug-in protector be effective? Question that Bud avoids answering.
So tell me again how this multiport plug-in protector intercepts or diverts? Where are the two functions of protection - equipotential and conductivity - provided by that plug-in protector? How does a plug-in protector that costs tens of times more money per protected appliance somehow out perform well proven 'whole house' techniques? How does it provide equipotential when the room violates what is necessary for equipotential? Three more questions that demonstrate why an earthed 'whole house' solution, instead, was advocated.
Martzloff, et al noted that plug-in protectors may even contribute to damage:
Not relevant? Earthing defines effective protection as even described by IEEE Green Book. Why claim grounding is "not relevant to surge suppressors"? Hundreds of citations note earthing as essential. An abridged summary list was posted on 30 Mar 2005 in alt.comp.periphs.mainboard.asus at:
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Then we have this backtracking:
Why waste m> 1) Quantitative measurements in the Upside-Down house clearly
Same author who recommends 'whole house' protectors in your cited paper on SRE (point of use or plug-in) protectors also says plug-in protectors may even contribute to damage. Yes, we demonstrated same by tracing how a transient entered and left a computer network. A plug-in protector provided more destructive paths through a computer - contributed to damage. Since that shunt mode protector provides no earthing, then a surge must go somewhere - such as destructively through an adjacent computer.
We learned about protection from transmitter sites and other high tech facilities. Where was early protection research conducted? On the Empire State Building during lighting strikes to transmitters. Lessons there proved how to best protect even homes. So why mock technical papers from those locations? Best knowledge for household protection comes from those commercial venues - as so repeatedly demonstrated by reams of citations.
Shame on Bud for totally misrepresenting what Polyphaser said. Polyphaser - a highly respected industry standard - is not recommending an equipotential solution from a SRE type, plug-in protector. Claiming that Polyphaser supports SRE claims means Polyphaser's paper was not read:
What was misrepresented as Surge Reference Equalizers (SRE) is actually 'whole house' protection. Polyphaser does not recommend ineffective solutions. SRE is protection only using 'equipotential' - ineffective. Polyphaser discusses protection using 'equipotential' AND 'conductivity'. Effective solution is also called 'whole house' protection.
How does one completely misrepresent that Polyphaser statement? Polyphaser states 'shunt' and 'earth ground'. 'Whole house' solution could not be more obvious. Meanwhile Polyphaser defines additional criteria for protection:
And again, connection to earth must be short - ie 'less than 10 feet'. What connection to earth is provided by a multiport, SRE, plug-in protector? Oh. Earthing is not even mentioned until his paper then recommends a different 'best' 'whole house' solution. A solution that provides both equipotential and conductivity to earth is not SRE advocated by Bud. Plug-in protectors remain unproven, are demonstrated ineffective, and can even contribute to adjacent transistor damage.
Another source: IEEE Red Book (Std 141) also recommends protection:
So where is this 'point of use' or plug-in solution recommended? As with all responsible citations for effective protection, earthing - not some multiport plug-in protector - is constantly recommended and discussed. How do we protect homes? We learn from radio transmitter stations, telephone switching office, emergency response centers, maritime communication stations, server rooms, and all those other facilities that were mocked instead of learned; that cannot suffer surge damage.
Finally Montandon and Rubinstein wrote a 4 Nov 1998 IEEE paper entitled "Some Observation on the Protection of Buildings Against the Induced Effects of Lightning". A direct strike to a building can create induced effects inside that building:
As usual when demonstrating protection even for homes, Montandon and Rubinstein use a telecommunication building with adjacent antenna towers. Yes, another transmitter tower site. With grasp and experience rather than mocking citations ("Surprise, surprise - another transmitter tower site."), then one learns concepts. Montandon, et al conclusions for equipotential as a solution eliminates SRE as a solution:
Figure 9 demonstrates problems created when utilities don't enter at a common point - a building wide common point and not some protector inside a room.
So where is equipotential established by point of use (plug-in) protectors? Demonstrated are problems created by improper cable entry to buildings, multiple bonding, and improper routing and bonding to ground. Solutions require lower impedance and better conductivity. SRE plug-in solution in a room does none of this. Due to current flows through everything within a building (that makes the SRE solution impossible), Montandon, et al demonstrate equipotential; better achieved by routing, bonding, and lower impedance. Same solutions that other citations discuss. Solutions that demonstrate why 'whole house' protection (that also costs less) is so effective. Solutions that demonstrate why plug-in protectors must avoid earthing discussions. Once we apply missing facts, then every claim of effective plug-in protector collapses. Plug-in protectors are not reliable protection. But they do cost more money.
Repeatedly cited is that need for earth ground - a system that provides both equipotential and c> ...
You have obviously not read, or not understood, the links I provided - ALL 3 recommend plug-in surge protectors. The IEEE paper CLEARLY describes how SREs work.
The issue is ONLY whether plug-in surge suppressors are effective.
Your sources may or not be interesting but do NOT say plug-in surge suppressors are ineffective; they say nothing about them. As usual, you change the subject.
The IEEE paper, referenced several times previously is
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- this is YOUR paper
- the title is "How to protect your house and its contents from lightning: IEEE guide for surge protection of equipment connected to AC power and cummunication circuits"
- much of its concern is 'transistor safety' - your favorite
- it was published by the IEEE in 2005
- the IEEE is the dominant organization of electrical and electronic engineers in the US and the publisher of some of your references
- the 5 authors have broad experience with surge suppression
Question: If plug in surge suppressors are not effective, why does the paper, divided into 7 sections, contain section 5: Multi-port point-of-use (plug-in) protectors section 6 Specific protection examples (all using SREs) Place your answer in a separate post from other responses.
If plug-in protectors were so effective, then why do responsible sources and responsible manufacturers instead discuss earthing and 'whole house' protection? Why then from that paper and from an author that discusses SRE; his own papers discuss superior and properly earthed 'whole house' solutions AND note that adjacent plug-in (point of use) protectors may even contribute to damage?
The issue is effective protection. Two types of protectors exist. Series mode and shunt mode. Series mode protect by stopping, blocking, or absorbing surges. Series mode protectors are not discussed here. Shunt mode protectors work by intercepting or diverting - words right out of the IEEE green book. SRE is a shunt mode protector.
So where is its earth ground connection? What does multiport SRE divert (shunt) to? Into adjacent electronics? What kind of protection is that? From generations of experience and without being part of a complete room solution: ineffective.
Somehow a multiport, SRE, plug-in (shunt mode) protector will work by only doing equipotential; by not doing conductivity? Equipotential does not work in a room that does not bring every one of six ports to a single point? Defined in that paper is one port that violates SRE effectiveness: enclosure port.
And finally, one will spend tens of times more money per protected appliance for this shunt mode protector that does not shunt to earth? More money for inferior protection that is even too close to transistors? These are damning questions demonstrated by reams of citations (IEEE papers, experience from industry professionals, lessons learned even on the Empire State Building, those so highly regarded application notes from Polyphaser, etc) on effective protection.
The bottom line fact remains: a protector is only as effective as its earth ground. A shunt mode protector must make the short (low impedance) connection to a single point earth ground. This solution provides both conductivity and equipotential; both necessary because neither is sufficient. An SRE solution (using a shunt mode protector) inside a room not specifically constructed to provide equipotential just does not work. And so even those authors of the SRE paper move on to discuss a 'best' 'whole house' solution.
Reasons why the SRE is not effective:1) shunt mode protector that does not provide conductivity to earth, 2) attempts equipotential in a room that violates that principle, 3) defined in a paper that then defines a 'whole house' solution as better, 4) costs tens of time more money, 5) would already be inside an appliance if so effective, 6) attempts to intercept or divert a surge too close to transistors - a problem identified and solved in transmitter tower sites and telephone switching centers so many generations ago, 7) and completely ignores what has long been demonstrated the most essential component in an effective protection 'system': single point earth ground.
Somehow this SRE would have eliminated what killed the cow? Yes, only if the room was part of the SRE solution - a faraday cage. Rooms just are not constructed to make that possible. Shunt mode protector that is effective must provide both equipotential and conductivity - because neither alone is sufficient.
How does electronics get best protected - and at least cost? Building is constructed with an Ufer ground. Best protection starts with architect's prints. We still don't build as if transistors exist. So we earth as best we can after not having done a superior solution up front. Protection 'system' is only as effective as its earth ground. Plug-in protector manufacturers hope we never learn that fact.
As I have said, surge protection at the power service entrance is a good idea. But the issue is ONLY whether plug-in surge suppressors are effective. "That paper and from an author" - what paper and what author. What "responsible sources and responsible manufacturers". As always, you have no links that directly address plug-in surge suppressors. And then you change the subject.
How about larry moe 'n curlys insurance company and Consumer reports. Are they "irresponsible"? Its you against the world, and now even against larry moe n' curly.
The IEEE paper, referenced several times previously is
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- this is YOUR paper
- the title is "How to protect your house and its contents from lightning: IEEE guide for surge protection of equipment connected to AC power and cummunication circuits"
- much of its concern is 'transistor safety' - your favorite
- it was published by the IEEE in 2005
- the IEEE is the dominant organization of electrical and electronic engineers in the US and the publisher of some of your references
- the 5 authors have broad experience with surge suppression
Question: If plug in surge suppressors are not effective, why does the paper, divided into 7 sections, contain section 5: Multi-port point-of-use (plug-in) protectors section 6 Specific protection examples (all using SREs) Place your answer in a separate post from other responses. I guess in your excitement you forgot to explain this.
What is performed by both plug-in protectors and 'whole house' protectors? Where does every buck spend provide (enhance) protection? Where does labor and parts result in significant transistor safety? Among many points - plug-in protectors cost massively more for inferior, if any, protection. Either we spend and enhance effective 'whole house' protection, or we waste time and money on protectors from less responsible manufacturers. Less responsible? Show me where a plug-in manufacturer even claims protection from transients that cause damage? You cannot. Plug-in manufacturers do not make that claim. Where are the numbers listing each type of transient? Not provided.
Every cited paper - and now we add Mike Holt to the list - does not blindly recommend plug-in protectors. These papers discuss merits (pluses and minuses) of such protection; noting inferiority problems using plug-in protectors. Spend tens of times more money and still get less - if any - protection? Why does Mike Holt say, "properly used"? He demonstrates numerous problems with plug-in protectors. Below is a sampling of why plug-in protectors are compromised AND can even contribute to adjacent appliance damage.
Figure 8 shows a plug-in protector adjacent to TV1. How much voltage difference between that protector and earth? 8000 volts. Is that TV going to charge up to 8000 volts and not find other, destructive paths to earth? Of course not. 8000 volts can find paths - some destructive - to earth via appliance. 8000 volts again demonstrates why protection must be located at service entrance - why plug-in protectors are not effective. Mike Holt makes a specific reference to "properly used", and demonstrates why plug-in protectors can even contribute to damage of adjacent electronics.
How curious? A point 1 in that Martzloff, et al paper says same thing:
Mike Holt puts numbers to an objectionable voltage - 8000 volts.
How many papers make a same po> Figure 8 shows a very common improper use of multiport
Remember - they are shunt mode protectors. They shunt transients to earth - to provide both conductivity and equipotential. Mike Holt also notes what a plug-in protectors must do:
How curious. The protector works by connection to earth ground. Why does the plug-in protector manufacturer 1) not provide the dedicated earthing connection, and 2) does not discuss earthing? Why does plug-in manufacturer avoid discussing that 8000 volts? That's 8000 volts that will find other earthing paths within the room - except if the room is constructed as part of the protection.
Why would a plug-in protector connect currents back to an earth ground that was ignored by that same current at the 'whole house' protector? Think what is claimed. If earth ground at the 'whole house' protector cannot earth a transient, then why would that same transient seek that same earth ground via a plug-in protector? If current cannot obtain earthing at the 'whole house' protector, then a transient through a plug-in protector will find other (potentially destructive) path to some other earthing inside the room.
Where is labor, money, and time better spent? Enhancing service entrance earth ground; not buying grossly overpriced and ineffective plug-in protectors. If earthing is not sufficient, then what will plug-in protectors earth to? Less money better spent fixing the reason why a transient was not earthed before entering a building. Money better spent on fixing the real problem - insufficient earthing.
Mike Holt recommends plug-in protectors in Section 5? Au contraire. Mike Holt cites numerous reasons in Section 5 why plug-in protectors fail. Martzloff, et al make a same point with 'six ports'. Any one port violated, then damage can result. How curious that a Martzloff paper (knowing full well that most every lurker here will not comprehend these 'six ports') then moves on to recommend a 'whole house' solution.
Will a layman appreciate 'six ports' defined in a Martzloff paper? Of course not. Yet all 'six ports' must be understood to make a plug-in protector effective. Mike Holt further defines multiple reasons why a layman cannot "properly used" plug-in protectors.
Mike Holt demonstrates another plug-in protector problem:
Five points are listed. Then Mike Holt describes the problem:
What is the homeowner to do when information is not readily available? Instead obtain conductivity and equipotential by properly earthing effective 'whole house' protectors. Earth trasnsients long before they get into the room.
BTW, Bud, everyone has a limited budget. $100 or $10,000 does many times more at the 'whole house' as compared in plug-in protectors. There is no separation between 'whole house' and plug-in solutions. It all comes from the same dollar bills. More of one means less of the other. Plug-in protectors typically cost tens of times more money for inferior and complicated protection.
Consumer must understand all six ports? Consumer must answer Mike Holt's five questions? Solution in a room not even designed to be part of the protection system? No wonder plug-in protector manufacturers don't say how or why their products work. No wonder they will not tell you, me, and every lurker what is necessary for a 'point of use' protector - earthing. What did Mike Holt define to make a plug-in protector effective?
And because that path is too far, the voltage different is listed in his figure as .... 8000 volts.
And so again - this time from Mike Holt - we have THE most critical component in every protection system: **earthing**.
Mike Holt describes how a plug-in protector even causes damage to TV1 and TV2 in figure 8.
Show me every housewife who will address all those grounding questions? Most men lurking here don't even fully understand the concept. And yet that is what Mike Holt demonstrates - what Martzloff calls the 'six ports'. Any one path to ground not part of a multiport protector means electronics damage. Or what was described previously as no equipotential.
Again, a plug-in protector may simply make electronics damage possible - even to powered off appliances. Just another reason why effective protection in transmitter tower sites, telephone switching centers, 911 emergency response centers, etc all put protection at a single point earth ground AND distant from electronics. Notice that last phrase: effective protection is located "farther from electronics".
Where in Section 5 does Mike Holt recommend plug-in (point of use) protectors. Instead he describes, multiple times over, why plug-in protectors fail to protect.
Mike Holt describes another problem with plug-in protectors:
Why would one recommend spending more money on a plug-in protector that has so many compromising complications? Even all its MOVs don't get used in protection. Carefully address everything in Section 5; what Martzloff calls 'six ports' are necessary to make protection effective. Even room construction must be considered. Smart money installs a 'whole house' protector AND enhances the most critical 'system' component: earthing.
Less technical expertise, labor, and money provides a superior solution - a 'whole house' protector and single point earth ground. An effective solution even sold under more responsible manufacturer names such as Cutler-Hammer, Leviton, Polyphaser, Siemens, Square D, and GE. A solution found in Home Depot, Lowes, and electrical supply houses. A simpler solution that is standard protection even in high reliability facilities such as maritime communication stations, cell phone towers, and every telephone switching station. Do they use plug-in protectors? Of course not. They want effective protection - not complications and hype. Protection is defined by and is as effective as its earth ground.
Every dollar wasted in plug-in protectors is better spent in the 'whole house' solution - especially in earthing.
Don't ask me why a home insurance company did not first learn the science. Ask them? If they know a plug-in protector is effective, then they have provided reams of facts that I did not learn after numerous decades of doing this stuff. Always looking for new facts - which is why IEEE always demands reasons 'why'.
I don't see Consumer Reports recommending protectors. What issue? What date? Why no specific citation or quote? Why is being an electrical engineer sufficient to be knowledgeable on transient protection? What kind of assumption is that? Instead post technical whys and whys nots - with quotes and numbers (technical reasons) from that article. Why do you think Bud - and rightly so - has trouble with any citation he cannot read in long and painful detail. Where are those details from Consumer Reports?
Sun Microsystems no longer provide their Planning Guide for Sun Server Room. Therefore you had a problem with it - and rightly so - because you could not review what Sun recommends in a server room. Meanwhile larry moe 'n curly provide no date or issue, no numbers, no direct quotes, .... nothing. And you don't have a problem with that? Why the double standard? Why was your next post about what could very easily be nothing more than a rumor - some speculation about a CR recommendation? He provided no citation, no numbers, and not a single reason (from CR) why a plug-in protector is recommended. You have no problem with such posts?
Major progress - IEEE (NIST, ...) now are recognized as recommending plug-in surge protectors. There are, of course, pluses and minuses for any protection scheme. Not obvious what other "cited paper" you refer to.
This paper is not Mike Holt's. It is from the IEEE. Mike only provides a link to it. If Mike provided a link to the Bible, it would not become Mike's document.
The IEEE provides this example to show how a SRE can protect the first TV, and says that protection is effective. The IEEE paper says a second SRE is needed at the second TV. If the CATV entrance is distant from the power entrance, as this example describes, there can be a large difference in the ground potential at the CATV ground block and the power service ground, 10 kV as this example describes. A single point ground reference at the power service for all incoming wires is desirable but not always present.
In additon, the CATV ground block, as you have said, provides no surge protection for the signal conductor - the limit being the flashover voltage at connectors. IIRC the IEEE paper said this was about 4 kV, which could appear at the TV antenna connection. The SRE has surge protection on this wire, which is not provided in 'whole house'.
No link, or even name provided for paper. Hey, wasn't that a major issue for larry moe 'n curly's reference to Consumer Reports??
The whole point of SREs is that they protect against this exact hazard.
You need to learn how to read. The IEEE (not Holt) provides section 5 to show how SREs can provide protection, and follows with section 6 to demonstrate specific examples of protecting with SREs. To say the IEEE doesn't recommend SREs is remarkably dense.
A MOV clamps the voltage across its terminals. Surge supressors fundamentally clamp the voltages on the protected wires to a common reference point. We both agree the ground path fom an receptacle to the power service panel is relatively high resistance. The protection provided by plug-in surge supressors is primarily by clamping, the conduction to earth is secondary. In the fig 8/fig 9 TV example, most of the earthing of the surge on the CATV service is via the "Coax sheath ground bond" from the CATV entrance ground block to the power service entrance (IIRC the paper says that).
The plug-in protector works primarily by clamping. Essentially the whole problem in this thread is that your religous views recognize only earthing, not clamping. The IEEE recognizes SREs are effective, thus action primarily by clamping can be effective.
'Whole house' and single point ground are good ideas.
For power/phone/CATV/... entrances not immediately adjacent you won't have single point ground. CATV ground blocks don't arrest surges arriving on signal wire. Surges can arrive in other ways. Plug in surge protectors can provide protection, as recognized by the IEEE (and others).
Most men (and women) lurking here can read the IEEE paper and understand it better than you.
[The IEEE says Joule ratings are substantially meaningless.] Every protection scheme is a series of tradeoffs. The circuit of 6B, with the protected equipment downstream from the fuse, will disconnet the protected equipment with the MOV. And the manufacturer may or may not set the fusing to an appropriate level. The IEEE doesn't seem to see this as a critical problem. Surge protectors installed at the electrical service also have overcurrent protection which is subject to the same problem.
================================================================ Another relevant article is
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This is an article from "Electrical Construction and Maintenance" magazine reviewing the book "IEEE Recommended Practice for Powering and Grounding Sensitive Electronic Equipment" (the Emerald book in the color book series)
A quoted definition from the IEEE Emeral book is: "Surge reference equalizer. A surge-protective device used for connecting equipment to external systems whereby all conductors connected to the protected loads are routed, physically and electrically, through a single enclosure with a shared reference point between the input and output ports of each system."
With comment from the article: "It has been found that, with multiport loads (such as computers with AC power input and data communication ports, televisions with AC power and CATV ports, or fax machines with AC power and telephone ports), a transient voltage surge event on one port, even if protected by transient voltage surge suppressor (TVSS), causes a transient voltage surge to be impressed across the other ports, often causing damage to the load equipment. One potential solution is the use of a surge reference equalizer to prevent differences in the ports' ground references under transient voltage surge conditions."
Fig 8 from the IEEE paper above is repeated in the book, and SREs are recognized as a tool in protecting electronics - same as the IEEE paper above.
Bud describes differential mode protection. Destructive transients are common mode. Yes a MOV can clamp (short circuit) a voltage between two wires. And that transient is typically not destructive. Differential mode transients are not typically sourced by lightning. Typically destructive transient is common mode. Clamping between two wires only puts that common mode transient on both wires - and still seeking earth ground.
Defined previously were two computers connected to plug-in protectors and powered off. A destructive transient was clamped by MOVs inside adjacent protectors. Now that destructive transient has more paths into the adjacent computer. That transient took paths provided by clamping in an adjacent protector. Incoming on AC wire. Outgoing on network. Down network wire to a third computer. Out that third computer via a modem and phone line to earth ground. Each damaged IC in that path was replaced; computers worked again.
Adjacent protectors did clamp the transient. Transient was clamped right into a destructive path through computers. Telephone switching centers don't put protectors adjacent to electronics for same reasons. Telco prefers shunt mode protectors to be up to 50 meters away from electronics - and short distance to earth. Why? As demonstrated above, clamping adjacent to electronics can even contribute to electronic damage. Clamping at the earth ground shunts (diverts, connects, intercepts) a destructive transient to earth long before it can find earthing paths destructively through electronics.
Fig 8/9 TV example demonstrates but another 'sneak' path that contributes to damage. Why. Clamping was too close to electronics and too far from earth ground. Rooms are constructed with 'sneak' paths everywhere. Just another reason why clamping must be at the earthing connection. That IEEE paper (previously attributed to Mike Holt) demonstrates too many ways for a plug-in (point of use) protector to fail; even contribute to electronics damage.
Shunt mode protectors are effective when shunting (clamping) short to earth ground. Plug-in protectors (also called shunt mode devices) hope you never learn about the typically destructive transient AND why shunting must be both short to earth and distant from electronics.
Bud is describing protection from a transient that typically does not do damage AND that is made irrelevant by protection already inside all electronics.
Why is the 'whole house' protector so effective? 1) It shunts or clamps all types of transients. It does that clamping distant from electronics. 2) It does that clamping short to earth. It is properly sized. 3) It connects to what shunt mode protectors need to be effective: single point earth ground. Not just any ground. A short connection to single point earthing. Clamping is ineffective if no earthing to clamp to. Earthing that provides both equipotential and conductivity. And yes, both conductivity and equipotential are necessary for shunt mode devices to be effective. MOV not clamping to earth (above example) even contributed to damage of three networked computers. I have seen such damage too often to believe plug-in protectors are worth ten times more money per protected appliance.
Why are 'whole house' protectors so effective? A short connection to (clamping to) earth ground determines effectiveness. Earthing being the protection. Protector being nothing more than a temporary connection (clamping) to protection. Protector being only as effective as the protection it connects to: earthing.
To provide both conductivity and equipotential, the clamping of a typically destructive transient is best distant from protected electronics AND as short as possible to earth. Such protection effective for all type of transients - and costs many times less money.
Consumer Reports reviewed surge protectors Nov 1994. I know you want to look it up to check the statements of larry moe n' curly, but could all
3 of them be wrong?
Bud does not describe differential mode protection. Bud describes protection for any surges on power (and signal) lines. You don't (can't?, won't?) get it.
Differential mode(surge lifts hot, neutral and ground not affected): MOV from H-N clamps the voltage. MOV from H-G clamps the voltage. If the N-G voltage is separated the MOV from N-G clamps the voltage. If the signal line has a ground (as CATV) it is connected to the power ground. All signal wires (CATV signal, phone, LAN, ...) have protectors (MOV, gas discharge, whatever) that clamp the voltage on that wire to the common ground at the SRE. ALL wires are clamped to the common SRE ground, a local single point ground.
Common mode(surge lifts hot and neutral, ground not affected): MOV from H-G clamps the voltage. MOV from N-G clamps the voltage. If the H-N voltage is separated the MOV from H-N clamps the voltage. If the signal line(s) have a ground (as CATV) it is connected to the power ground. All signal wires (CATV signal, phone, LAN, ...) have protectors (MOV, gad discharge, whatever) that clamp the voltage on that wire to the common ground at the SRE. ALL wires are clamped to the common SRE ground, a local single point ground.
Surge on signal wires: If the signal line(s) have a ground (as CATV) it is connected to the power ground. All signal wires (CATV signal, phone, LAN, ...) have protectors (MOV, gas discharge, whatever) that clamp the voltage on that wire to the common ground. If power line voltages shift, a MOV from H-N clamps the voltage and a MOV from H-G clamps the voltage and a MOV from N-G clamps the voltage. ALL wires are clamped to the common SRE ground, a local single point ground.
In all cases the ground potential at the SRE may be different from the power service or signal entrance protectors.
(If the -{NID, CATV ground block, dish protector, phone-extension-to-the-garage protector, whatever}- are not immediately adjacent to the power service, and connected with short wires to the power service grounding electrode conductor at the service panel, the ground potential of the signal protector(s) will be different than the power service if a surge hits any of the protectors or the power service.)
(Clamping is not a short circuit.)
The IEEE (NIST, ...) say SREs are effective protection.
Perhaps you missed that the IEEE paper said SREs are effective.
Bud is describing protection from ALL surges AND
Provide a link affirming that electronics is effectively protected from surges by internal devices.
2 If the -{NID, CATV ground block, dish protector, phone-extension-to-the-garage protector, whatever}- are not immediately adjacent to the power service, and connected with short wires to the power service grounding electrode conductor at the service panel, the ground potential of the signal protector(s) will be different than the power service if a surge hits any of the protectors or the power service. This is not an uncommon sitution, and is illustrated in the IEEE paper, fig 8. Resulting surges, as you have often said, can be fatal to the equipment.
If the power service does not have surge protection the energy dissipaton capacity of internal devices is likely not high enough to protect
If the power service does have a surge protector, the service clamp voltage is generally high, to give long life and low 'aging'. The clamp voltage at the electronics is typically much lower. The result is the devices at the electronics still conduct and can be destroyed.
Power line surges shunted at the equipment can lift the ground at the equipment from the power service ground. (This is your common complaint about plug-in surge suppressors.) This effectively puts a surge on the signal wires which the device may not handle (the same point you make about plug-in (not SRE) surge protectors).
A CATV ground block does not protect the center conductor. The IEEE paper IIRC said this voltage can reach 4 kV at (at which point there is flashover at the connectors). This voltage can appear at a TV, or other equipment, which might not like the voltage.
NEVER fly in an airplane. They seldom drag an earthing chain while flying, leaving their avionics totally exposed to lightning. (I'm sure there is a major coverup of the frequent plane crashes.)
The IEEE (NIST, ...) say SREs, which I certainly agree have a poor earthing connection, are effective protection.
----------------------------------------------- Other surge protection devices and schemes may be a good idea but the issue is ONLY whether plug-in surge suppressors are effective.
The IEEE (NIST, ...) say SREs are effective protection.
Do you disagree with the IEEE (NIST, ...)? Are you smarter than the 5 electrical engineers that wrote the IEEE paper?
Consumer Reports did normal mode testing of protectors in 1994. APC once provided numbers for normal mode transients. But neither that Consumer Reports test nor APC made any claims about a type of transient that typically does damage.
CR then made some very abridged claims in 2000. However something strange happened. Suddenly CR eight year indexes starting 2003 dropped all references to surge protector reviews. Those 2000 reviews should remain in the CR indexs until 2008. But by 2003, CR makes those 2000 tests difficult to find. Tests that provide few details and apparently did not test per how damage typically occurs.
Larry, Moe and Curly did discuss many things. However they also could not tell us What's on first, Who's on second, and Where is third. Important questions of that age. Today, we only google for live's little questions.
This discussion was completely about terrestrial protection. But same principles - conducting lightning to the earth ground (or outgoing connection) also apply to planes. Aircraft designers have it far more complex. Unlike a terrestrial building, a single point earth ground can be anywhere. They must design everything in terms of layers - layers of earthing - which is well beyond the scope of this discussion. For example, the earth ground this time in this picture is quite obvious: plane's tail:
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Next time the outgoing transient path could be anywhere else. Planes are struck routinely without damage. Same principles that also define the 'whole house' protector so effective - conducting lightning in paths that are not destructive. Concepts of equipotential and conductivity even apply to airplanes. Same concept that must be applied with greater care due to transients from and to more directions.
Review that famous picture. Plane conducted direct lightning strike; no problem.
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