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Let me guess Archangle -- you're an electrical engineer who deals with electronics -- voltages in the mV and current in the mA ranges -- right? I'm more accustomed to dealing with things in the kV range.

Quite a bit of what you say is indeed true -- some of it simply isn't.

Lightning arrestors on power systems regularly get blown by direct strikes -- you really think you can build consumer side protection on that order of magnitude?

Tip10 wrote:Let me guess Archangle -- you're an electrical engineer who deals with electronics -- voltages in the mV and current in the mA ranges -- right? I'm more accustomed to dealing with things in the kV range.

Quite a bit of what you say is indeed true -- some of it simply isn't.

Lightning arrestors on power systems regularly get blown by direct strikes -- you really think you can build consumer side protection on that order of magnitude?

First, you weren't the one I was calling clueless. Sorry, I should have been clearer.

You're making incorrect assumptions about my experience and knowledge.

I've never suggested that commercial grade lightning arrestors or whole house arrestors are a bad idea. I've commented several times that lighting will sometimes do what it darn well pleases. As I said, it can ignore the surge suppressors and everything else and come through the window and hit you directly. It can blow up the power company's equipment, your whole house surge suppressor, your power strip surge suppressor, and the CPAP machine's protective circuitry if any. Surge suppressors and other countermeasures only improve your odds.

I will say that there is almost no case where a surge suppressor directly at the CPAP machine decreases your protection. There are a lot of cases where it will save your CPAP machine.

Sorry, my bad also.
I suspect our backgrounds, or at least our chosen education is pretty similar.

I got into the discussion late and probably should have just stayed out of it -- you were doing quite well on dealing with correcting most of the BS that was flying in the thread.

Have a good one.

archangle wrote: As I said, it can ignore the surge suppressors and everything else and come through the window and hit you directly. It can blow up the power company's equipment, your whole house surge suppressor, your power strip surge suppressor, and the CPAP machine's protective circuitry if any. Surge suppressors and other countermeasures only improve your odds.

According to your subjective reasoning, ET stealing a CPAP is just as likely. An engineer would have posted numbers. You never do.

Lightning blows up a 'whole house' protector when a layman invents strawmen. Provided were numbers that define effective protection. Lightning is typically 20,000 amps. A minimally sized 'whole house' protector from responsible companies is 50,000 amps. It does not blow up. But when educated by advertising, one claims, “The surge suppressor will often give its life to protect the circuitry inside your CPA machine.”

Sacrifice? What happens if too few joules during a destructive surge (tens or hundreds of thousands of joules)? Either it disconnects as fast as possible. Leaves a surge connected to a CPAP. Or sometimes it does not disconnect fast enough. Scary pictures result:
http://www.ddxg.net/old/surge_protectors.htm
http://www.zerosurge.com/HTML/movs.html
http://tinyurl.com/3x73ol entitled "Surge Protector Fires"
http://www3.cw56.com/news/articles/local/BO63312/
http://www.nmsu.edu/~safety/news/lesson ... orfire.htm
http://www.pennsburgfireco.com/fullstory.php?58339

Sacrifice itself? He obviously did not learn numbers that say why scary pictures occur. An engineer did. Energy was permitted inside because an earthed 'whole house'protector was missing.

A damning and constantly ignored question is, “Where are power strip specs that claim any protection?” A pseudo engineer avoids numbers. Obviously. No power strip claims that protection. One cannot post what does not exist. No problem. Subjective hearsay is proof.

If really an amateur radio operator, then you would know this stuff. Hams discuss this constantly. For example, multiple articles in QST entitled "Lightning Protection for the Amateur Radio Station”. Protection for their equipment or a CPAP is always about earthing. Either a surge is connected directly to earth (cable TV, satellite dish). Or earthed via one ‘whole house’ protector (AC electric). Sun Microsystems demands same for Sun Server rooms. US Air Force requires it in training manuals. AT&T is blunt about earthed protection in "How can I protect my DSL/dialup equipment from surges?” Munitions dumps do not waste money on power strip protectors. Protection is required. They earth ‘whole house’ protectors because nothing inside a munitions dump must *sacrifice* itself. Engineers do not spend tens or 100 times more money on scam power strips. But you do.

Best protection means lighting strikes and other energy is not anywhere inside a house. So that power strips do not create scary pictures. So that protection is what engineers have been doing for over 100 years. The OP asked for CPAP protection. Least expensive solution is also the superior one. Earthing one ‘whole house’ protector so that ineffective protectors do not ‘sacrifice themselves’ or threaten house fires. Cheapshots and empty accusations do not help anyone.

Informed CPAP owners earth one ‘whole house’ protector. Do not waste money on power strips recommended only by hearsay, subjective claims, and cheapshots.

westom's understanding of the physics of surge protection is very flawed.

However I agree that:

1) A whole house surge suppressor is a good idea.
2) A whole house surge suppressor is probably better than most individual surge suppressors.

On the other hand:

3) I doubt that many people who read this will get a whole house surge suppressor installed.
4) A whole house surge suppressor is not 100% protection for everything in the house.
5) Those without whole house suppressors will improve their odds by using individual surge suppressors on their CPAP machines.
6) Those who do have whole house suppressors will improve their odds by using individual surge suppressors on their CPAP machines.
7) Most whole house surge suppressors or individual surge suppressors have a light you need to check periodically to see if they're still working. The suppressor may need replacement occasionally.
8) When you're using the CPAP away from home, you don't have the choice of a whole house surge protector.

archangle wrote: 4) A whole house surge suppressor is not 100% protection for everything in the house.
5) Those without whole house suppressors will improve their odds by using individual surge suppressors on their CPAP machines.
6) Those who do have whole house suppressors will improve their odds by using individual surge suppressors on their CPAP machines.

Again the numbers. A 'whole house' protector properperly earth will do 99.5% protection. Those numbers from the IEEE Green Book entitled 'Static and Lightning Protection Grounding'. A plug-in protector will do maybe another 0.2% of the protection.

Without earthing a 'whole house' protector, a plug-in protectors can:
1) sometimes make CPAP damage easier (as demonstrates by an IEEE brochure that shows a protector earthing a surge 8000 volts destructively through an adjacent TV),
2) can create those scary pictures (have even created house fires),
3) is typically undersized to even trip a fail light (that says it was grossly undersized - ineffective),
4) does not claim to protect from typically destuctive surges (no spec numbers),
5) will not even discuss the always so critical earth ground (so NIST calls it "useless"),
6) has an obscene profit margin compared to $1 per appliance for a 'whole house' protector,
7) is not the solution in facilities that cannot suffer damage, and
8 ) must be protected by earthing a 'whole house' protector.

Best road protection is already inside a CPAP if a plug-in protector does not compromise that internal protection. More effective that the plug-in protectors is something that is typically insufficient for household protection - unplugging.

Yawn.

westom wrote:A pseudo engineer avoids numbers.

Hmmmm.....

westom wrote:Cheapshots and empty accusations do not help anyone.

Perhaps you should stop making them then!

The bottom line is that close-by or direct lightning strikes are going to kill semi-conductor junctions (the things inside the integrated circuits that make most contemporary electronic devices, such as xPAP machines, work) dues to the massive dV/dT spike created in the local ground plane.... effectively its almost like a localised EMP effect in terms of outcomes. There's not a lot that can be reaslistically done to prevent that at the sort of investment level an individual domestic consumer is likely to be able to sustain

Cable-born spikes from more distant lightning strikes are a different matter, and may able able to be protected again at affordable levels for individual domestic consumers.

billbolton wrote: The bottom line is that close-by or direct lightning strikes are going to kill semi-conductor junctions (the things inside the integrated circuits that make most contemporary electronic devices, such as xPAP machines, work) dues to the massive dV/dT spike created in the local ground plane.... effectively its almost like a localised EMP effect in terms of outcomes. There's not a lot that can be reaslistically done to prevent that at the sort of investment level an individual domestic consumer is likely to be able to sustain

True as long as we conclude subjectively - ignore numbers. Or automatically believe what is promoted by advertising and hearsay. And if we ignore what was already posted.

A lightning strike near a long wire antenna can create thousands of volts on that antenna. Then we earth it with an NE-2 neon glow lamp. A milliamp through that lamp reduces thousands of volts to tens of volts. Because induced energy of nearby lighting is near zero. That induce surge is promoted only when numbers are ignored.

A direct strike to a lightning rod meant tens of thousands of amps – the entire lightning bolt – flowing to earth on a wire. Four feet away from that wire was an IBM PC. The entire lightning current, according to you, must have vaporized the PC. Reality. The direct lightning strike only four feet from a PC that did not even blink. Please learn the numbers and technology before assuming so many myths. Nearby strikes (induced surges) do not cause damage. Direct strikes are why we earth surge protectors.

Four feet from an IBM PC? How much higher must dV/dT be for that urban myth to finally become hearsay?

Obviously, a lightning strike took out every nearby car radio, television, mobile phone, and wrist watch. Reality. None of that was damaged. EMP myths are popular - and mythical. Subjective reasoning can make anyone an ‘expert’.

A milliamp through an NE-2 neon glow light eliminates energy of a nearby strike. And contradicts popular myths. Please learn what was already posted before repeating these legends. An overwhelming majority are educated by subjective legends; not by science.

Informed homeowners and CPAP users earth one 'whole house' protector so that lightning strikes and other typically destructive surges cause no damage. Some also earth lightning rods to eliminate a less frequent event - a building strike. Nearby strikes and the resulting EM fields are made irrelevant by protection already inside every appliance – including a CPAP.

Realistically, EMP does not cause damage. EMP causes fictional damage. As defined in earlier posts.

billbolton wrote: Cable-born spikes from more distant lightning strikes are a different matter, and may able able to be protected again at affordable levels for individual domestic consumers.

Best protector for cable is a copper wire. Code requires cable to connect by wire to earth ground. Earthed where cable enters the building. A reply to roster explained how that cable earth ground must be installed to make nearby direct lightning strikes irrelevant.

Cable companies recommend no plug-in protector on their cable. Why would anyone waste that money? Best protector for cable is a wire. Resulting protection is made even better by making that connection shorter to single point earth ground. And upgrading that earth ground. Apparently it was not explained enough times?

Protection for CPAP means no surge energy enters a building on any wire.

westom wrote:True as long as we conclude subjectively - ignore numbers.

Numbers are meaninglessly huge for close-by and direct strikes.

westom wrote:Informed homeowners and CPAP users earth one 'whole house' protector so that lightning strikes and other typically destructive surges cause no damage.

That seems a very subjective statement to me.

westom wrote: Realistically, EMP does not cause damage. EMP causes fictional damage. As defined in earlier posts.

Your version of real is clearly VERY different to mine then.

In any case, the issue is not EMP, just outcomes which are very like the effects of EMP but on a very localised scale. The underlying physics of a close-by and direct lightning strikes is different from a nuclear detonation EMP, but the outcome is quite similar for the electronic systems in the vicinity of a close-by and direct lightning strike.

westom wrote:cable earth ground must be installed to make nearby direct lightning strikes irrelevant.

When the whole immediate ground plane is at a much higher potential than the nominal ground plane was just microseconds previously, it is never irrelevant to PN junctions.

billbolton wrote: The underlying physics of a close-by and direct lightning strikes is different from a nuclear detonation EMP, but the outcome is quite similar for the electronic systems in the vicinity of a close-by and direct lightning strike. ...
When the whole immediate ground plane is at a much higher potential than the nominal ground plane was just microseconds previously, it is never irrelevant to PN junctions.

Surge protection is about equipotential. That means a ground plane may increase 5000 volts. And to all interior electronics, that is near zero volts across every PN junction. If everything increases by 5000 volts, then obviously no voltage exists inside. Concepts that define how a Faraday Cage works.

Examples: 1) Why do cars suffer direct lightning strikes and keep operating? Because the entire car increases thousands of volts. Therefore no electronics or occupant is harmed. No potential difference exists inside.

2) Why does a bird land on a 33,000 volt wire and remain unharmed? Same thing. Bird is at the same 33,000 volts as the wire. That is zero volts to the bird.

Nobody is discussing NEMP. I don't know why you mentioned it.

Equipotential is why earthing must be single point. Why protection increases when enhancing the earthing system. Why every wire (overhead and underground) connect to single point earth ground before entering. And why power strip protectors without a dedicated wire to earth ground are ineffective.

As long as every wire enters as was done 100 years ago, then voltage inside a building stays at near zero while the ground plane can even increase thousands of volts. Same concept in a car directly struck. Same concept of the bird sitting on a 33,000 volt wire.

Ground potential rise (GPR) is just another reason why plug-in protectors are ineffective protection. Will not discuss GPR or earthing. And why a power strip protector can make CPAP damage easier. Effective protector always has that short connection to single point earth ground. GPR is just another reason why.

GPR is also why the NIST defines plug-in protectors as useless:
> A very important point to keep in mind is that your surge protector will work by
> diverting the surges to ground. The best surge protection in the world can be
> useless if grounding is not done properly.

A radio station demonstrates how nearby strikes and GPR are made irrelevant using a lightning protection technique pioneered in munitions dumps:
http://scott-inc.com/html/ufer.htm
Protection is always about earthing – not about the protector’s obscene price tag. Nearby and direct strikes constantly while the most surge sensitive semiconductors (CMOS) remain unharmed. They installed what does all protection – a ‘whole house’ protector connected short to better earthing.

GPR and EM fields are completely different. GPR is made irrelevant by proper single point earth ground. Why ‘whole house’ protectors are so effective. And why plug-in protectors are so ineffective as to avoid the entire topic. EM fields made irrelevant by superior protection existing inside all electronics – even in wrist watches and mobile phones. An IBM PC only four feet away from an entire lightning strike did not even blink.

Equipotential and GPR: more reasons why CPAP owners need one 'whole house' protector properly earthed - and nothing else.

westom wrote:And to all interior electronics, that is near zero volts across every PN junction.

It not anywhere near zero at the instant of the strike/back strike!

Here's what one whole of house surge protection vendor as to say...

http://www.euroelectrical.com.au/Surge%20Protection.html wrote:Be aware that a direct lightning strike to your property will result in damage and no level of protection - within a reasonable budget - will prevent this!

By the way I also found this on Whirlpool.....

westom wrote:Perhaps you are not the engineer I thought you were. Surge protectors utilising MOVs as their active component absorb nothing at all. For the benefit of the OP, a MOV is, in layman's terms, a voltage switch. When the voltage exceeds a certain level, the MOV suddenly changes from an insulator to a conductor. The excess voltage then bypasses your device and is effectively short-circuited across the MOV.

So where does it conduct that energy to? Through the safety ground? Of course not. Obvious if you learned the well proven technology and other parameter such as wire impedance.

Why does the 'whole house' protector connect 'less than 3 meters' to earth? Because it DOES connect energy harmlessly to earth.

What does a plug-in protector do? It has virtually no earth ground. Best it can do is earth that surge destructively via adjacent appliances. That is obvious when wire impedance is added to the circuit. That is obvious when simply concept from over 100 years ago are learned. That is obvious when one learned why the earth ground must be short, no sharp wire bends, no splices, not inside metallic conduit, separated from other non-grounding wires, etc. Plug-in protectors violate all this. SO – the only thing a plug-in protector can do is absorb hundreds of thousand of joules.

Basic knowledge or experience from some of the 100 years knowledge says we install protectors to make direct lightning strikes irrelevant. A lightning strike down the strike to utility wires is a direct strike to household appliances.

Well, you never learned basic wire concepts. Earth ground and safety ground are not same. Electricians who never learn these concepts may confuse different grounds. Safety ground is not same as earth ground. The unavoidable requirements for earthing a protector make that even more obvious. Safety grounds have too many sharp bends, splices, bundled with other wires, does not make that so essential 'less than 3 meter' connection to earth. To promote ineffective (and so highly profitable) plug-in protectors to the naive, a salesman needs you to never learn these basic electrical concepts. He fears if you discuss fundamental concepts such as wire impedance.

Unfortunately you do not have basic knowledge necessary to understand what was well understood even 100 years ago. What Telstra must do in every switching center to suffer typically 100 surges with each thunderstorm – and no damage.

Plug-in protectors do not even claim protection in its numeric specs. You would know that if not educated by popular myths or retail shelves. If you had the essential technical knowledge, then it would have been obvious that this engineer even designed protection – that earthed direct lightning strikes without damage. You would have known that the effective and minimally sized protector starts at 50,000 amps. AND that a protector is only as effective as its earth ground – which you would have known is not same as a safety ground in the wall receptacle.

Clipsal is one source of effective protection. What does the plug-in protector without earthing do? We who do this stuff learned even saw it during the autopsy. Plug-in protector even earthed a direct lightning strike through a network of adjacent and powered off computers. Obvious when one learn how electricity (surges, lightning) works, why wire impedance is a critical parameter, why Telstra does not waste money on ineffective plug-in solutions, AND why a protector is only as effective as its earth ground.

Earth one 'whole house' protector so that all surges – even direct lightning strike – cause no appliance damage. So that even the protector is unharmed. Protection is always about where energy dissipates. Once inside a building, that energy hunts for earth destructively via appliances – with or without a plug-in protector. More reasons why a protector is only as effective as its 'less than 3 meter' connection to single point earth ground.

Bullshit is when someone foolishly recommends power strip protectors. Even the manufacturer will not claim that protection in its numeric specs – as you have kindly demonstrated.

2010-Jan-13 http://forums.whirlpool.net.au/forum-re ... 55461&#r14

I have also discovered many other forums that Westom has posted similar things to, over and over again. I invite anyone here who cares, to put the term "what was well understood even 100 years ago" into Google and read for themselves.

No need to Bill, as an engineer with over 30 years experience in the power industry I can easily recognize his stuff for what it is -- mostly gibberish.

He raises a few good points -- a properly grounded whole house surge protector is indeed the better protection, he fails miserably in his statements that its the only protection, as well as in his statements that it is complete protection.
In addition his "engineering" of the dynamics of a surge (he erroneously seems to believe that lightning is the only thing that can cause a surge) and in particular lightning induced surges is, shall we say, from somewhere out beyond left field.

I suspect he also is extremely ignorant of US building codes -- residential, commercial and utility.

Tip10 wrote: He raises a few good points -- a properly grounded whole house surge protector is indeed the better protection, he fails miserably in his statements that its the only protection, as well as in his statements that it is complete protection..

I never said 100%. As I said, proper earthing and 'whole house' protector is * 99.5% * of the protection. I made the statement. And quoted the source. With numbers. How to convert near zero protection from power strip protectors to something like 99.5% protection.

Critical to surge protection is what some power companies have no respect for. Earth ground. An earthed 'whole house' protector is only ‘secondary’ protection. Also important is a ‘primary’ protection system. But in some power companies, engineers are trained to cost control. Then assume a "failure is acceptable" attitude. Even blame missing power strip protectors (blame consumers) rather than fix their defective or insufficient earthing. Homeowners are encouraged to inspect their ‘primary’ protection system. A picture of what must be inspected:
http://www.tvtower.com/fpl.html

First Energy is a benchmark for engineers who blame consumers. Some towns had so many earthing defects as to pass laws. $5000 per day fines for each day the defective ground existed. Only then would power company engineers fix earthing. These same cost controllers would blame homeowners for their surge damage and other problems. Even claim nothing was perfect rather than admit that 99.5% of surges need never cause failure.

If power strip protectors do any useful protection, then manufacturer spec numbers are posted. I keep asking anyone to post even one number that claims effective protection. Naysayers such as billbolton post empty accusations and subjective claims. Numbers for protection? Where are his numbers?

A perfect example is billbolton’s citation from electricians at http://www.euroelectric.co.au. His ‘authority’ is a sales brochure. His ‘authority’ does not even know how a ‘whole house’ protector works.

The device monitors your grounding system for excessive voltage levels between neutral and ground. If it detects an unusual level, power is shut down before it affects the inside of your property.

No effective protector works that way. By now (if he bothered to read what was posted) he should have seen that obvious mistake. No protector disconnects to protect from a surge. He should have known that before he cited them as his ‘expert’. But again, many in denial are educated only by advertising. Explains his so many subjective posts and acidic denials.

Describes are eight reasons to waste money on plug-in protectors. Scary pictures alone should be reason enough to avoid those profit centers. Those who foolishly recommend them will not even post one manufacturer spec numbers. Will not even make useful recommendations – which means manufacturer spec numbers. Those educated by advertising only naysay.

Any protection system that does not protect from lightning is wasted money. Protection that makes direct lightning strikes irrelevant also protect from all other types of surges. Lightning is a benchmark. If your protector does not protect from lightning, then it is money wasted.

Any surge that can overwhelm protection inside a CPAP is made irrelevant by earthing a ‘whole house’ protector. Because effective protectors makes all surges irrelevant. And remains functional even after direct lightning strikes. Only those with an advertisers education might deny that. As billbolton demonstrated by quoting advertising from Australian electricians.

Posts denials. Never posts a useful solution. IEEE provides the well proven solution. Properly earth a ‘whole house’ protector: "Still, a 99.5% protection level will reduce the incidence of direct strokes from one stroke per 30 years ... to one stroke per 6000 years ... "

He said I claimed 100% protection. I did not. That was his latest cheapshot accusation. Reducing the incidence of surge damage to less than maybe 0.3% for only $1 per protected appliance is by far the best and only needed solution for a CPAP and everything else. Only fools and others such as billbolton (educated by advertising) will recommend scam power strip protectors. A power strip does not even claim protection from destructive surges. Will create scary pictures. And still a majority will recommend it. Best protection for a CPAP was always only one properly earthed 'whole house' protector. One can learn from 100 years of well proven science. Or one can do what advertising orders them to believe. Many are easily brainwashed by advertising at $25 and $150 per appliance. It's more expensve. It must be better.