w_tom Yes or no did you repeatedly state that connections to water pipes are only for removing electricity? Remember only a yes or no answer is acceptable! Any other answer is a duck and dodge.
Antenna towers are likely to take a direct lightning strike resulting in huge currents. A house is not exposed to anything vaguely resembling that over its power/signal lines, nor to the effects from direct induction. I remember no post to any thread that thought a house could be protected from a near strike on a power line. You would have to explain how tower protection is relevant to a house. But don't bother - see next point.
"A protector is only as effective as its earth ground. No earth ground means no effective protection." This seems to be very basic. If true it should be easy to find support the basic science, the concepts. I asked for a single specific paper at Phaser that is relevant. You seem to have forgotten.
Regarding Dr. Mansoor I deferr to Charles Perry: "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."
Regarding Martzloff and others - sorry but I want to read what they say, and in context. Got a link?
Wow - an actual link. Oh - rats, what I get is:
"Effective January 1, 2005, EPRI PEAC has been merged into EPRI Solutions, Inc., a subsidiary of the Electric Power Research Institute (EPRI). You will automatically be redirected to
Sorry, that one came from Perry. However it does advocate plug-in point-of-use surge suppressors. NIST believes they provide protection. And you did supply the link
None of them I read did. But I am so happy. Because it will be easy for you to provide one or two reputable links that clearly support "A protector is only as effective as its earth ground. No earth ground means no effective protection." Hey - didn't I ask for links in my last post? Did you forget?
Kindly don't supply 30. I don't have the time and have become disillusioned.
Oh, personal testimony endorses astrology and even more bizare beliefs. Something scientific would be nice.
......
Article 250 of the NEC was extensively reorganized in 1999.
2005-250.52-A-1 is the direct descendant of 1999-250-81-a. All comments about being removed/obsolete are wrong. And water pipe "can be added" is wrong - it "must" be added (if 10 ft...).Many people have contested your water pipe posts. We are quite aware that a supplemental electrode is required. It is very unlikely anyone would challenge "water pipe is no longer acceptable as an only earthing electrode" from this post. But "water pipe is no longer acceptable as an earth ground", from previous post, has a different meaning.
Many reasons? Name several.
--------------------
From your (w-tom) posts in a recent thread [with my comments]
"Water pipe must be bonded to AC electric for human safety reasons. The only electrical connection acceptable to pipes are connections that remove electricity. This for many reasons including future use of plastic pipe and plumber safety. No longer acceptable to wire electrical devices to water pipes with intent of making that water pipe a safety ground. Electric wire connections to water pipes are permitted only to remove dangerous electric currents from those pipes."
[Appears to me to say a water pipe may not be used as a grounding electrode. Also, with the grounding electrode conductor attached within 5 ft of the entrance and the meter bonded, there is a hazard to a plumber? And I never have figured out what "remove electricity" is.]"What some non-electricians are having a problem with are other electrical and electronic reasons why a water pipe ground is not sufficient. Involves parameters that concern engineers - that include and go beyond an electrician's code requirements. Remember, code is only about human safety. But the earthing system also performs other functions - such as transistor safety."
[You are arguing that a ground rod provides superior earthing to a water pipe. Ground rods (and plates) are the only electrodes that must have their ground resistance measured (25 ohms is "good") - unless 2 rods are installed, then ground resistance can be over 25 ohms. I have seen stated typical ground resistance values of 3 ohms for municipial water systems. But ground rods are better?]Two reasons why water pipe earthing is no longer sufficient. NEC requires water pipe be bonded to AC electric safety ground - for human safety reasons. NEC requires other electrodes (2 through 7) for earthing.
[Appears again to say a water pipe may not be used as a grounding electrode.]
This should have been an independent point - I thought of that after posting.
bud--
Yes, 'structure earthing' is a topic different from the original surge protector and surge protection question. But it does have a distant relationship since earthing also defines whether a surge protector is effective. That relationship dicussed later.
Article 250.81(a) began a series of changes in building earthing - in what is considered sufficient. Originally a building (home) used water pipe bonding for two purposes:
Point First: to remove electriticy from pipes so that a human could not be electrocuted. Other items might be bonded to those pipes (ie telephone line) because water pipes were considered a good safety ground.
Point Second: breaker box was bonded to water pipes as an only electrical earth ground. Code considered water pipes as a low resistance and reliable earthing.
Along comes plastic replacement pipe. Code also began considering safety of plumbers who, while standing in water, might disconnect a pipe and be electrically shocked (right there are two of 'many' reasons). Code changed. Any grounding for human safety must use devices dedicated only for that electrical purpose (reliablity - another reason). Water pipes are not intended primarily for electrical earthing - therefore water pipes are no longer sufficient for earthing. Water pipes are not intended primarily for electrical bonding - therefore anything that must be bonded cannot use (connect to) water pipes for that human safety ground function. In short, any connection to pipe must be only to remove electricity - not dump electricity into a pipe
Safety cannot be obtained by dumping electricity into pipes for many reasons including the most obvious - plastic pipes.
We still meet the original purpose of above Point First. We bond - a connection from cold water pipe to breaker box safety ground - to remove electricity from pipes. We cannot make any electrical connection to pipes anywhere in the building to dump electricity into those pipes as was once considered acceptable. And we bond to remove electricity from those pipes.
From Mike Holt at:
Point Second: 'earthing a building' again says that water pipe is no longer sufficient for earth ground - use of plastic pipe is only one reason why. Code lists six other earthing electrodes that are acceptable. So why is cold water pipe still on that electrode list? If cold water pipe was removed from the list, then cold water pipe must include an electrical isolator between interior water pipes and buried pipes - similar to what is often found on some natural gas pipes. That isolator would be rediculous - counterproductive. So we don't completely ban cold water pipes as an earth ground. We make the electrical isolator unnecessary by saying water pipes are earthed; but are not sufficient for earthing. Cold water pipes no longer provide earthing requrired by code - they are not sufficient.
We don't demand an electrical isolator between undergound and interiior pipes. But cold water pipes (in most cases) are no longer sufficient for earthing as demonstrated by previous quotes from the NEC and even the above Mike Holt explanation. Since 1990, electrical service must have some other earthing solution AND that earthing solution must be close to every incoming utility. That's right. Code states distance to earth ground even for cable TV and telephone.
Above defines earthing and bonding only for human safety. Now we go one step farther - earthing for transistor safety. Code does not consider transistor safety except where those transistors might threaten human life. But we humans also need transistor safety. And code is written to make that protection easier. For transistor safety, we need a short, direct and independent connection from each incoming utility to a single point earth ground. Reasons why are beyond the code and often are not understood by electricians. Code only addresses human safety issues; not transistor safety issues.
Some utilities, such as coax cable, require no surge protector to have surge protection. That coax cable connects directly (hardwired) to a dedicated earth ground. Other utilities (telephone and AC electric) require a short earthing connection via surge protectors. We now have a relationship between earth ground and our main topic - surge protectors. We now have but another reason for a dedicated earth ground. Remember, I said there were many reasons - not just plastic pipe.
As noted so many times previously, a surge protector only *diverts* a surge to earth ground. Surge protectors provide no protection. Protector is simply an electrical connection device - similar in function to a switch. Protector connects surge protection to each wire inside each utility cable.
Too often, cold water pipe is too far away to perform earthing. But again, a distant cold water pipe is not sufficient for earthing. Earthing connections must be less than 10 feet for transistor safety. Just another reason why a building uses any one of those other six earthing electrodes defined by National Electrical Code (NEC). Superior earthing provided by Ufer or halo grounds - if we really addressed transistor safety.
Cold water pipe grounding once served two functions - bonding (remove electricity from water pipes) and earthing (connect breaker box to earth ground). Point First function remains as it did 30+ years ago. Point Second function is now located elsewhere. A third and recent function - surge protection - typically requires earthing not sufficiently provided by cold water pipes.
Of course many people contest my posts - as described above. I would not post if others were not posting half truths, misguided assumptions, wlld speculation, or just confused. I have no interest posting where the informed are posting accurately. I post where myths are common. Notice that Tom Horne's reply was intended to be confrontational - not provide useful facts. For that matter, Saddam clearly has weapons of mass destruction because well over 70%believed it. I didn't. I first read those reports from advanced physics labs and other sources; where facts and numbers rather than speculation were provided. But I must have been wrong because 70% said otherwise. Number of who disagree means nothing. Otherwise Saddam has WMDs. You don't care about how many disagree. You worry about underlying facts and numbers. Provided are many facts and even a quote from the NEC as to why cold water pipe is no longer sufficient for earthing.
Code is written (Article 250.52) so that an electrical isolator need not be put on cold water pipes. We earth for numerous reasons. Reasons that also make a surge protector effective. Cold water pipe is no longer sufficient for earthing.
Meanwhile, the sound byte: a surge protector is >
You *still* don't understand that energy will be absorbed & dissipated when current flows through a resistance? P = I^2 * R where P is the power dissipated in the resistance of the protector, I is the current through the protector, and R is its resistance. QED - the protector will dissipate surge energy.
To say it will only divert a surge is blatantly wrong. You cannot get around the laws of physics, no matter how often you post that incorrect idea.
The remaining points below in your post, predicated on that misconception, are wrong.
Ed
Because "energy will be absorbed & dissipated when current flows through a resistance" then the purpose of wire is to absorb and dissipate electrical energy. Surge protectors, like wire, will dissipate some energy when performing their function: to conduct, shunt, divert, transport that electricity. Shunt mode protectors do not to suppress, absorb, dissipate, or arrest energy as ehsjr repeatedly claims over so many years. Although some energy is dissipated (neither wire nor protectors are perfect conductors), well, a one hundred joule protector will absorb how many joules in a lightning strike? (One joule is one volt and one amp for one second: how many in lightning?) How many joules will that 100 joule protector suppress, absord, or arrest?
A wire diverts (conducts) energy to my vacuum cleaner. How many joules has its power cord suppressed, absorbed, dissipated, or arrested? About 3700 joules. Well that proves it. The purpose of a power cord is to absorb electricity. Meanwhile the power cord carries another 3,456,000 joules into the vacuum cleaner. Irrelevant. That wire dissipated / absorbed energy. Absorbing enery must be its purpose.
When ehsjr posts this same refrain, a credible source is cited in reply. This time the National Institute of Science and Technology is quoted from in their publication 960-6 entitled "Surges Happen! How to Protect the Appliances in your Home.":
ehsjr wrote:
You clipped your innacurate statement that is the bone of contention: " As noted so many times previously, a surge protector only *diverts* a surge to earth ground."
Your second sentence below admits that surge protectors will dissipate some energy. Congratulations! But then you contradict yourself in the next sentence, saying "shunt mode protectors do not suppress, absorb, dissipate ..."
You mention what you call a credible source. Here's what it says to that question: "Joules -A (simplified) measure of the surge energy that the protector can dissipate without damage to itself. The higher the value, the more energy the protector can handle. Typical values range from about 100 joules, up to 1000 joules or more. Because this joule number is often based on the three combinations of the wiring, many specifications show the total joules rather than a breakdown among each of the three combinations. Maximum surge current (below) may give better information."
Your comparison is ridiculous. The valid comparison is of the MOV to the vacuum cleaner, not to its cord. Just look: -------
-------------|Vacuum |
-------------|Cleaner| ------- ---
-------------|MOV|
-------------| | ---
The document you mention can be found here:
Note that most of these have a two-prong plug, which is their sole connection to the power system. For the TV set, a simple" AC plug-in surge protector on the power cord would be sufficient." ...
"A simple solution to the problem of voltage differences for two-link appliances is to install a special surge protector that incorporates, in the same package, a combination of input/output connections for the two systems. Each link, power and communications, is fed through the protector which is then inserted between the wall receptacles and the input of the appliance to be protected. This type of surge protector is readily available in computer and electronics stores, and the electrical section of home building stores."
Your source denies your mantra that point of use protectors are no good or offer no protection or whatever variation. The source is credible according to you. You picked it, I did not. Polyphaser, which you often cite, sells point of use protectors, which again opposes your position. Your physics is wrong, your example is pure smokescreen. You have admitted that point of use protectors absorb energy - you have even posted pictures dramatically proving that they do.
Your incessant drivel that protectors are not protection, or that point of use protectors are not effective, or whatever variation you use serves only to dilute and discredit some of the excellent points you do make. It's really simple. Good protection starts with a good ground system. Relying solely on a point of use protector is a crap shoot - it might protect your equipment, and it might not.
Ed
to 100 joules"
Yes - while same MOV typically diverts many thousands of joules to earth ground. Ed tells us a transient of 101 or 200 joules will damage a 100 joule MOV. Of course not. ehsjr was provided numbers so many years ago which he apparently did not understand. A wire also dissipates joules when it carries thousands more joules elsewhere. My vacuum cord dissipates 3000 joules while delivering (diverting) millions of joules to that vacuum cleaner. But since the vacuum wire does not degrade with use, then we don't rate that wire in joules. We rate MOVs in joules because MOVs degrade (not burn out - degrades) when acting like a wire.
MOV life expectancy is measured in joules. Posted so many times previously to ehsjr - who ignores numbers he apparently cannot understand. A 40 joule MOV (2V130) dissipated 0.6 watts during what? A 25,000 watt transient. So what happened to the other 24999.4 watts? ehsjr forgets those numbers from 5 years ago. Some silly idea that an MOV absorbs near 100% of a transient.
Yes, a 100 joule MOV can dissipate 100 joules or more (depending on other transient parameters) - while MOV diverts many thousands of joules to ground. Again, a protector is only as effective as its earth ground - where the transient is dissipated. Ed simply spins a half truth into some idea that a 100 joule transient will be dissipated by a
100 joule MOV. Somehow his myth: a plug-in protector located between a TV and a power receptacle will absorb a direct lightning strike. It will stop what three miles of sky could not. Total nonsense used to promote ineffective plug-in protectors. When properly installed, a protector diverts a transient to earth ground.Ignoring repeated spin that Ed has posted over so many years - and moving on to numbers provided by MOV manufacturers. As the number of MOV joules increases, then number of transient joules dissipated in earth ground increases exponentially.
MOV joules from manufacturer charts estimate MOV life expectancy. MOV manufacturers provide charts for MOV joules verses transient current verses impulse time verses number of transients. MOV joules measures an MOV life expectancy which is a number different from many times more joules that are diverted.
MOV dissipates energy - as a wire does. When an MOV - or a wire - dissipated 100 joules, many times more energy is dissipated elsewhere. ehsjr tells us the purpose of that wire or MOV is to absorb all transient's energy. He uses junk scientist reasoning. Notice he provides no numbers from manufacturer datasheets.
A 10000 volt 100 amp impulse of maybe 14 joules arrives at an earthed MOV. According to Ed, almost all of up to 1000000 watts are dissipated in that MOV. Not true for one minute. MOV with a threshold voltage of
200 volts dissipates maybe 0.3 joules. Where is the rest of that energy dissipated? In this example, diverted to earth ground is well over 90% of the energy. Notice why a protector is only as effective as its earth ground. Notice where the energy is dumped - dissipated.Why do we rate MOVs in joules? Suppose that MOV is rated at 2 joules. Manufacturer life expectancy chart says it will divert 10 identical transients before degrading (not vaporizing or 'burned out' which is unacceptable for MOVs). If that MOV increases to 5 joules, then chart estimates degradation after 500 transients. 500 transients at 0.3 joules - about 150 joules dissipated by a 5 joule MOV. 10 transients by a 2 joule MOV - 3 joules dissipated when MOV has degraded. An MOV that is 2.5 times larger has a life expectancy 50 times larger. Welcome to what MOV joules measures - life expectancy.
Notice the emotion that ehsjr posts:
Some cannot post facts and numbers. So they insult. That sentence demonstrates his frustration. Above are numbers from an MOV manufacturer datasheet. ehsjr is posting half accurate facts. Ed forgets to provide a whole story. Why? If the purpose of a protector is to divert to earth, then the plug-in protectors are not effective. Which plug-in protector company or reseller does Ed work for?
Yes MOV dissipates energy - just like a vacuum cleaner power cord dissipated energy. Using ehsjr half truths, then purpose of that power cord is to dissipate energy. Meanwhile the purpose of a shunt mode protector is to *divert* that energy to earth ground - as Franklin lightning rods also do. Ground: what plug-in protectors avoid to promote their ineffective products. A protector is only as effective as its earth ground.
If a power cord had a life expectancy, it too would be rated in joules. But joules - to measure MOV life expectancy - are not the number of transient joules diverted as Ed would proclaim. An effective shunt mode protector *diverts* - no matter how many times I get insulted by ehsjr.
Meanwhile another industry professional - Sun Microsystem from their Planning guide for Sun Server room Section 5.4.7 Lightning Protection (Adobe page 89):
To sell > To answer the question you posed about how many joules will
to 100 joules"
You previously stated: "As noted so many times previously, a surge protector only *diverts* a surge to earth ground."
Now you have recognized and stated that an MOV style protector
*absorbs* energy.Therefore, you cannot truthfully maintain your position that point of use surge protectors are not effective, or are usless or that they provide no protection or whatever way you put it.
The degree of effectivness is a completely different matter. A point of use protector can be overwhelmed, as can a whole house protector, if energy in excess of what they can absorb appears at their terminals. But until the surge kills them, whatever surge energy does appear at their terminals, they absorb, in accordance with ohm's law. You can't get around P = I^2R where R is the resistance of the MOV and I is the current through it.
Talking of the energy in a lightning strike is pointless. What matters is the energy that arrives at the MOV's leads. Provided it is sufficient to cause the MOV to go into clamping mode, the MOV will attempt to absorb the energy at its leads, or die trying.
Are you really so desparate to attempt to support your position that you compare a wire in series with a load, to an MOV which is in parallel with the load?
The wire you mentioned is in series with the vacuum cleaner. The MOV point of use supressor is in parallel with the device plugged into it. If you make the proper analogy, the wire you are talking about would have to be placed in parallel with the vacuum cleaner. And it would vaporize, long before millions of joules reached your vacuum cleaner.
Your lack of understanding of a series vs a parallel circuit explains why you think as you do on this subject.
With something that glaringly wrong, the rest of your post is not worth a response.
Ed
It would be nice, particularly in an engineering forum, if you could find a clear unambiguous description to replace "remove electriticy from pipes".
"Dedicated only for that electrical purpose"? You are also excluding structural metal framework, and Ufer grounds. Of the 6 electrodes required to be included, if present, only water pipe and structural framework are required to have grounding electrode conductors (GEC) increase in size as the service size is increased. Ufer does not have to be larger than #4 and rods/plates does not have to be larger than #6. It would seem the NEC views water pipe and structural steel as an effective electrodes, with a greater grounding capacity that other electrodes.
You said there were "many reasons besides plastic pipe for why cold water pipe is not sufficient as an earthing ground." You give here: Plumber safety. Cite a source. And since a water pipe is still required to be a grounding electrode how is this a reason. One? = "many"?
[By water pipes I mean burried >10 ft.... and especially municipal metal water pipe systems.]If intended only for bonding, the NEC required bonding conductor would be much smaller than the GEC that is actually required.
The link is actually a IEEE document, "How to protect hour house and its contents from lightning" probably of great interest to any one still on this thread, very good - good post. I presume this quote is that connections cannot be made directly to a water pipe for communications protectors or other earthing or bonding purposes (although, IIRC, they can be made within 5' of the entrance). I presume it is not saying water pipes can't be used as a ground electrode because the NEC requires them to be used as a grounding electrode.
From page 7:"The NEC/CEC requirements for connecting all metal piping and large metal parts of the structure to the building ground serve two purposes: If there is metallic buried water piping, bonding it to the building ground improves the quality of that ground. Also, in the rare event of a direct strike to the piping, or to a metallic part of the structure, the ground bond conducts the lightning currents safely into the building ground."
Cite a source that agrees with your isolator argument.
I'm not aware any signal utilities required a dedicated earthing. In any case the NEC requires all earthing to be tied together into one system. And we both believe in single point ground where power neutral-ground/bond connection and signal protector earthing connection are tied with minimal length and earthed together. Dedicated earth ground??
In your excelent Holt/IEEE post, Fig 7 illustrates a TV protected by a plug-in point-of-use multi-port surge suppressor. The illustration has a cable ground block remote from the electrical service and attached to it by a ground wire. The cable has a lighting strike and the ground current lifts the cable ground block 10kV above the service panel. At the TV the cable is at 10kV with respect to the TV, not recommended. With a multi-port suppressor installed, at the suppressor (at the TV) the cable ground is connected to the power ground. These points thus will be at the same voltage although that voltage will be thousands of volts different from the electrical service and the cable ground block. Since the surge suppressor clamps hot, neutral, and cable center conductor to that local reference ground the TV is not damaged although it is at thousands of volts above ?absolute' ground. The TV has not been protected by diverting the surge to ground but by clamping all wires to a common reference point.
This illustrates protection primarily by clamping action, not diversion to ground - common to plug-in suppressors. Plug-in suppressors are strongly supported by this - your - link. Also by another of your links and the NIST in a previous post.
In the meantime you have not furnished one or two links that clearly demonstrate that "only" diversion works. Musta forgot again
In your case it seems to be 100% to 0%.
Hmm - I'm right and everyone else is wrong - sounds like paranoid schizophrenia.
Of course there are numerous reputable links - "facts and numbers" - supporting your views - you just forgot to include them - again.
bud--
Purpose of connecting (bonding) breaker box safety ground to water pipes is to 'remove electricity'. Yes, that is it not technically explicit. Yes, there are exceptions. Should I post a thesis on this - or did you read code for further details? Where is that purpose incorrect? No, the code does not explicity define the purpose. But what it demands is repeated and even summarized by Mike Holt. Connecting to pipes to safety ground a device - to 'dump electricity into those pipes' - is no longer acceptable.
Telephone line, once grounded anywhere inside building to cold water pipes (as was so common in the 1960s), is no longer acceptable. Cable TV wire cannot be 'earthed' to outside water faucet. Telephone ground can no longer be made to pipes as was standard in the 1960s. We connect wires to pipes only to 'remove electricity'. And not just electricity that might short to interior pipes. We also must 'intercept' a current that may be coming from outside mains. Cold water pipe must be bonded where it enters building - required by code for human safety. Electricity must be removed from pipes.
I need not cite sources for plumber protection. We have changed the code whereever plumbers would be at risk. A ground wire must bypass water meter so that plumber need not fear things electrical. A bypass ground must connect hot pipe to cold pipe so that hot pipes are safety grounded AND so that a plumber is not at risk if changing that hot water heater. We bond for human safety so that even a plumber standing in water need not be harmed when disconnecting a pipe and need not have electrician's knowledge. Review of code will demonstarte many new requirements that now protect the plumber - which was long overdue.
Structural metal work or Ufer ground: why do you misrepresent what NEC demands? NEC defines the acceptable (and sufficient) six earthing electrodes. Other earthing electrodes are not permitted. If cold water pipe was not a seventh item in the list, then code water pipe would require electrical isolation. The list is specific; what is only permitted for earthing. Structural metal work and Ufer ground are listed in Article 250.52(A) making your question puzzling. Did you read the code; a list of what is acceptable for earthing?
Cold water pipe is specifically listed as not sufficient in Article
250.53(D)(2). Code lists what is only acceptable as an earthing electrode - including Ufer ground, et al - AND code states that cold water pipe is not sufficient for earthing.You posted:
You could only post this is you did not read Article 250.52(A).
Why is cold water pipe still listed as an earthing electrode? Because if cold water pipe is not an earth ground, then cold water pipe connected to breaker box must be electrically isolated from earthing. Code is specific what can and cannot be an earthing electrode. Cold water pipe can make a connection to earth ground BUT cold water pipe is no longer sufficient as the ONLY earth ground (exceptions exist that are well beyond the scope of this discussion).
#4 AWG is sufficient for earthing. Anything to improve that earthing is totally irrelevant to code and irrelevant to whether cold water pipe is sufficient to earthing. Why do you disparage #4 AWG wire because water pipe has a larger diameter? Water pipe with a larger diameter makes the #4 AWG wire insufficient? Nonsense. Irrelevant both to what code says and what is discussed here.
Furthermore, if we built new homes for transistor safety, then water pipe - what you regard as a better earthing electrode - would be an electrically inferior ground. Transistor protection is defined first and foremost by earthing. We earth for reasons in code (human safety) and then we also earth for transistor safety.
Why are you confusing communication ground with electrical ground (citing Mike Holt quote)? Code wants communication and electrical earthing to be common. Obviously earthing can become more complex in industrial environments. But a residential communication and electrical electrode should always be at same point. Code even states maximum permissible length for each earthing wire. We also need that common earthing point for transistor safety - another requirement beyond scope of code and that defines effectiveness of a protector.
Mike Holt's example of protectors insists that even 'point of use' protectors be grounded. Why? Protectors earth a transient. What must it 'clamp' to? Earth ground. IOW 'clamping' is also 'diverting' a transient to ground. Why do you confuse 'clamping' with 'diverting'? Mike Holt defines grounding essential which is why I am so mystified why you have misrepresented 'clamping':
Goes right back to a protector's purpose. An effective protector 'diverts' transients to earth as so many responsible and previously cited sources state. Manufactures selling ineffective plug-in protectors ignore all that hoping you never learn what a protector must do. An effective protector clamps / diverts a transient to earth ground.
Obtain appliance protection using 'point of use' protectors to obtain equipotential - as is discussed by Mike Holt. But be very careful. Anything that violated equipotential makes a plug-in protector solution ineffective - as Mike Holt notes. Any one path violating equipotential and the entire protection is compromised. An appliance wire drapes down to floor. Equipotential violated. Table electrically connected to floor or wall. Equipotential violated. Peripheral cable draped onto adjacent baseboard heater or air duct. Equipotential violated. Equipotential at the equipment requires a total room-wide analysis. Like a wooden church steeple, even tables, linoleum tile, and wall paint must be considered - all may be conductors. Every incoming electrical connection to an appliance must first make the single point connection. Good luck accomplishing that inside rooms not constructed accordingly.
Notice how equipotential and 'point of use' protection gets complex - and plug-in protector manufacturers avoid this. Mike Holt introduces requirements for using 'point of use' protectors. Most important, Mike says a 'whole house' protection system is still required even if using plug-in protectors.
Let's see. We pay $20 (or $100 for Monster Cable products) per appliance. How many appliances? 50? Or we spend much less money to enhance a building's earthing. Enhanced earthing means a transient is less likely to overwhelm protection already inside an appliance. Did that plug-in protector manufacturer also forget to mention protection already exists inside appliances? Curious how many facts that manufacturer will forget to mention. Previously demonstrated was how a plug-in protector can even contribute to damage of a powered off computer - subvert or bypass existing internal protection. Damage demonstrated by literally tracing the surge and replacing each damaged IC. A destructive path made possible by an adjacent plug-in protector.
Yes you can attempt equipotential at each appliance, spend massively more money, and also create these risks:
'Point of use' protectors can provide some protection ... from transients that just are not typically destructive. Spend so much more money and yet not get same protection that can be obtained from enhancing 'whole house' protection - for tens of times less money. Not effective also explains why so many plug-in protectors are grossly undersized. Grossly undersized - the internal MOV vaporized - which is not an acceptable failure mode. And yet above pictures demonstrate the problem.
Telephone COs connect to overhead wires everywhere in town. Why is that telco computer undamaged every year? Telco wants protectors that connect short to earth and are ideally 50 meters distant from the computer. Yes, that separation between protector and electronics enhances protection. Yes a shortest connection to earth enhances protection. A 'whole house' protector with superior single point earth ground is more effective - and costs so many times less money. Why would anyone spend $100 for a Monster Cable product? No separation. No dedicated and short connection to earth. It does not even claim to protect from typically destructive transients.
But again, purpose of a protector: made obvious by what an MOV, an avalanche diode, a spark gap, a gas discharge tube (GDT), and even telephone line protectors installed on all phone lines 50 years ago - all do. Each diverts a destructive transient to ground. Each is 'clamped' to an earthing connection. Earthing is the purpose of shunt mode protectors - divert, clamp, connect, shunt a destructive transient to earth.
Def> It would be nice, particularly in an engineering forum, if you could
Did not forget. But a large number of facts have not yet been established. The answer (and I did not make that claim) is found long after basics have first been established. Because we can discuss SP200, first we must do SP101.
You are misinterpreting the Code. 250.50 explains that the electrodes listed in 250.52(A)(1) through (6) should be bonded together into an electrode system, *if they are present*. The purpose of this is to enhance the grounding system by combining all of these acceptable electrodes. The title of 250.52(A) is "Electrodes Permitted for Grounding". (A)(1) is a metal water pipe, and (A)(3) is a Ufer, so why are they different in terms of acceptability?
If none of those electrodes are present, then you need to install one or more of the types listed in 250.52(A)(4) through (A)(7). These are fabricated types of electrodes, and any other underground metal structures. This is a practical matter, since you wouldn't install an underground water pipe or building structure just for grounding. It has nothing to do with it not being acceptable.
No it doesn't. It allows the use of the pipe, but requires a supplemental electrode. This is to provide backup in case the water pipe is replaced with plastic, not because it is inadequate as an electrode. (See the explanation in the handbook)
250.52(B) lists the "Electrodes Not Permitted for Grounding". There are only two... underground gas piping (obvious reason), and aluminum. Water pipe is not on that list. Why do you insist that it is not acceptable?Ben Miller
Where does your post disagree with what was posted previously? Only where you have changed my wording. Code defines what is acceptable as an earthing electrode in Article 250.52(A). Fence post is not listed and therefore is not acceptable as an earthing electrode. Are you now saying the fence post can be used as an earthing electrode even though Code 250.52 does not say so? Of course not. Only earthing electrodes
- notice the word "acceptable" - are listed in Article 250.52(A).
Notice the word "sufficient" was not used because "sufficient" and "acceptable" have two completely different meanings. Article 250.52(A) lists only electrodes that are "acceptable".
Meanwhile if building uses only cold water pipe for earthing, then is building earthed "sufficient" for code? Of course not. Cold water pipe is an "acceptable" earthing electrode [per Artcile 250.52(A)], but it is not "sufficient" [per Article 250.53(D)(2)]. Does that mean cold water pipe as an earthing electrode is "not acceptable"? Again, of course not - as I stated how many times. You posted:
I never said that. You are not reading with care - and I repeatedly keep posting this point. The words 'sufficient' and 'acceptable' are not same. Why do you assume those two different words with completely different meanings are same when I even post sentences to demonstrate the two words as different? What is 'sufficient' and what is 'acceptable' are two completely different conditions. So many times posted was cold water pipe can be an earthing electrode (which obviously means 'acceptable'). BUT cold water pipe is **not sufficient** as an earthing electrode.
You are replacing "sufficient" in my posts with the word "acceptable". Why? Go back. I was very specific about the words "sufficient" and "acceptable". And yet somehow you (and Bud) still replace the word "sufficient" with a word of completely different meaning: "acceptable". Please reread what was repeatedly posted; taking care to differentiate "sufficient" and "acceptable". No matter how many times I demonstrate difference between "acceptable" and "sufficient", Bud insists those words have same meaning.
To repeat for maybe a 15th time: Cold water pipe is no longer
*sufficient* as a building earthing eletrode. That does not for minute, anywhere, anytime, say that a cold water pipe is not acceptable. What has changed since 1990? Cold water pipe that was once both "sufficient" and "acceptable" for building earthing now is only "acceptable" [Article 250.52(A)] and is "not sufficient" [Article 250.53(D)(2)]. Code is quite specific.Home owners of pre-1990 homes should c> ...
Where does your post disagree with what was posted previously? Only where you have changed my wording. Code defines what is acceptable as an earthing electrode in Article 250.52(A). Fence post is not listed and therefore is not acceptable as an earthing electrode. Are you now saying the fence post can be used as an earthing electrode even though Code 250.52 does not say so? Of course not. Only earthing electrodes
- notice the word "acceptable" - are listed in Article 250.52(A).
Notice the word "sufficient" was not used because "sufficient" and "acceptable" have two completely different meanings. Article 250.52(A) lists only electrodes that are "acceptable".
Meanwhile if building uses only cold water pipe for earthing, then is building earthed "sufficient" for code? Of course not. Cold water pipe is an "acceptable" earthing electrode [per Artcile 250.52(A)], but it is not "sufficient" [per Article 250.53(D)(2)]. Does that mean cold water pipe as an earthing electrode is "not acceptable"? Again, of course not - as I stated how many times. You posted:
I never said that. You are not reading with care - and I repeatedly keep posting this point. The words 'sufficient' and 'acceptable' are not same. Why do you assume those two different words with completely different meanings are same when I even post sentences to demonstrate the two words as different? What is 'sufficient' and what is 'acceptable' are two completely different conditions. So many times posted was cold water pipe can be an earthing electrode (which obviously means 'acceptable'). BUT cold water pipe is **not sufficient** as an earthing electrode.
You are replacing "sufficient" in my posts with the word "acceptable". Why? Go back. I was very specific about the words "sufficient" and "acceptable". And yet somehow you (and Bud) still replace the word "sufficient" with a word of completely different meaning: "acceptable". Please reread what was repeatedly posted; taking care to differentiate "sufficient" and "acceptable". No matter how many times I demonstrate difference between "acceptable" and "sufficient", Bud insists those words have same meaning.
To repeat for maybe a 15th time: Cold water pipe is no longer
*sufficient* as a building earthing eletrode. That does not for minute, anywhere, anytime, say that a cold water pipe is not acceptable. What has changed since 1990? Cold water pipe that was once both "sufficient" and "acceptable" for building earthing now is only "acceptable" [Article 250.52(A)] and is "not sufficient" [Article 250.53(D)(2)]. Code is quite specific.Home owners of pre-1990 homes should c> ...
Not only is it "not technically explicit" it is technically illiterate.
Hard to establish basics when you don't use understandable language.
Current score Against at least 2 electrical engineers at least 3 electricians numerous other people
For none
Links to sites establishing the same claims or supporting the basic science: none
bud--
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