Low Surge Energy Rating even for expensive Smart Online UPS's ... Why ?

[ahmadka]

I'd like to know why most (if not all) APC Smart Online UPS's have such low Surge Energy Ratings ?! Considering that these UPS's cost $2000 ~ $3000 a piece, one would expect them to have an exceptionally high Surge Energy Rating, higher than most common cheap surge protectors available in the market. But this is not so.

For example, THIS (need to click here) UPS only has a 480 Joules Surge Energy Rating, but the following cheap surge protectors offer almost 10 times the Surge protection, but cost only a fraction:

Belkin 12 Outlet Pivot Plug Surge Protector with 8 Foot Cord ~ 4320 Joules ~ $27.10

Tripp Lite HT10DBS Home Theater Isobar Surge Protector 10 Outlet RJ11 RJ45 Coax ~ 3840 Joules ~ $79.96

So why is this so ?

 

[westom]

I'd like to know why most (if not all) APC Smart Online UPS's have such low Surge Energy Ratings ?! Considering that these UPS's cost $2000 ~ $3000 a piece, one would expect them to have an exceptionally high Surge Energy Rating, higher than most common cheap surge protectors available in the market. But this is not so.

Who are they marketing to? A protector without a critical low impedance (ie 'less than 10 feet') connection to single point earth ground cannot do useful protection. But the electrically naive (ie many computer techs) do not know that. So, the UPS only needs a protector as tiny as possible. Just enough above zero to claim surge protection. Then the electrically naive know it must be 100% protection.

Protection means one can say where hundreds of thousands of joules are harmlessly absorbed. Faciliities that cannot have damage do not want what APC products do for surge protection. They cannot afford the damage, failures, and many times larger monetary costs. Instead, these facilities use what is proven by over 100 years of science and experience.

For example, best protection on a coax TV cable is a hardwire from that cable to single point earth ground. That hardwire connection MUST be low impedance (ie 'less than 10 feet', no sharp bends, separated from other non-grounding wires, etc). Then hundreds of thousands of joules harmlessly dissipate outside.

Telephone cannot connect directly to earth. So a 'whole house' protector is installed, for free, by your telco where their wires meet yours. That protector like all protectors does not do protection. That protector only does what a hardwire would do better.

No protector does protection - despite so many who recommend a UPS only on parables and hearsay. A protector either connects destructive energy to earth. Or it does almost nothing like protectors in all those APC UPSes.

You did something that most consumers never do. You viewed numbers. Then you saw what so many techs never see - perspective. APC has near zero protection. But just enough above zero so that most techs know it must be 100% protection. Others are experts at ignoring facts and numbers. Most only know the first thing they were told. A protector is only as effective as its earth ground.

 

[imagoon]

You would do best to ignore the Westom posts few if any of his points actual follow the National Electric Code Associations [NECA] recommendations nor requirements. Great example at this point is that there is no way for me to have surge suppression in my data center (per westom) because it is on the 13th floor of a building in Chicago and the multiple naught wires grounding the electrical rooms are over 400 feet to one of the 4 building structure grounds that are driven 75 feet in to the earth. Yet the grounds and surge suppression systems meet and exceed the city code requirements.

Anyway the simple answer is that you are buying a UPS and not a surge suppressor. They are not the same device nor the same function. It is possible that APC decided that it would be better to place the surge suppression outside the unit since it is the most common failure point.

 

[westom]

Great example at this point is that there is no way for me to have surge suppression in my data center (per westom) because it is on the 13th floor of a building in Chicago and the multiple naught wires grounding the electrical rooms are over 400 feet to one of the 4 building structure grounds that are driven 75 feet in to the earth.

Lightning protection is different from human protection. Codes only address human safety; not transistor safety. Had you learned this stuff, then you knew that obvious difference.

Second, you did not learn what both Westinghouse and GE published in papers in the early 1930s. On the 13th floor clearly means you should have earth grounds that are easily less than 10 feet. But then you did not learn why; did not read those GE and Westinghouse research papers. Did not learn why electronics atop the Empire State Building and World Trade Center (100 floors up) had earth grounds so good as to suffer 23 and 40 direct lightning strikes annually without damage.

Please learn this stuff before making accusations based only in speculation. That data center should have some of the best surge protection possible with low impedance connections to earth ... due to how a building is constructed.

You criticize rather than first learn this stuff. You did not even know that human safety codes do not define what is necessary for transistor safety. Anyone who first learned basic concepts would have known that. And obviously knew a low impedance connection to earth ground exists on a 13th floor. Please stop criticizing because you did not learn this stuff.

 

[imagoon]

Lightning protection is different from human protection. Codes only address human safety; not transistor safety. Had you learned this stuff, then you knew that obvious difference.

Second, you did not learn what both Westinghouse and GE published in papers in the early 1930s. On the 13th floor clearly means you should have earth grounds that are easily less than 10 feet. But then you did not learn why; did not read those GE and Westinghouse research papers. Did not learn why electronics atop the Empire State Building and World Trade Center (100 floors up) had earth grounds so good as to suffer 23 and 40 direct lightning strikes annually without damage.

Please learn this stuff before making accusations based only in speculation. That data center should have some of the best surge protection possible with low impedance connections to earth ... due to how a building is constructed.

You criticize rather than first learn this stuff. You did not even know that human safety codes do not define what is necessary for transistor safety. Anyone who first learned basic concepts would have known that. And obviously knew a low impedance connection to earth ground exists on a 13th floor. Please stop criticizing because you did not learn this stuff.

Good dodge and attempt to look wise. A+ would read again. PS I learned from the NECA guides and electrical engineers. They don't agree with you so I don't consider much value in "learning" your multiforum incoherent drivel. So Weston, please do what you say and "Please learn this stuff before making accusations based only in speculation." Who mentioned lightning?

PS I am done at this point because I am not in the mood to ready you 10000+ character unsupported rebuttals. There are thousands of posts on multiple forums that have shown your lack of knowledge on this subject.

 

[westom]

"Please learn this stuff before making accusations based only in speculation."

We have been over this many times. You refuse to learn how this stuff works. If you knew this stuff, then stated in electrical terms is why a low impedance earth ground connection cannot exist on the 13 floor despite well proven science from GE and Westinghouse. But again, insufficient knowledge is combined with a love for turning technical dicussions nasty.

Well I was trained by God - a three letter expresssion. And still do not use that as proof. Posted was why that APC UPS is near zero protection. It answers the OP's question. And what is always required to have protection - with technical numbers.

Concept is simple. Where do hundreds of thousands of joules harmlessly dissipate? Every facility (even 100 floor up on the WTC and Empire State Building) have that well proven solution - that does not exist with APC and its near zero joules protector.

Please stop making another thread nasty by posting your emotions ... without technical facts. And, as usual, no numbers. Please stop posting as if your four letter expression is even relevant. Any technician without engineering education can cite guidelines without understanding what it means. You do not know this stuff. APC is near zero protection due to near zero protector parts and no low impedance connection to single point earth ground. Their marketing of near zero protection is extremely profitable.

APC was even selling some protectors so undersized that, about a year ago, we learned they must be removed immediately to avert a house fire.
http://www.cpsc.gov/en/Recalls/2014/Schneider-Electric-Recalls-APC-Surge-Protectors/

PS OK, you now editted your reply to say you are leaving because you have nothing useful to contribute. Please, just once, stay away so that we can have an honest technical discussion.

 

[imagoon]

We have been over this many times. You refuse to learn how this stuff works

You must be looking in a mirror when you say this. You have been proven wrong for the better part of a decade and at least 25 forums where I have seen you post. My electrical engineering team even has posted some of your threads on the wall for the hilarity. Simply put, I don't consider anything you post as a valid source because it has been proven incorrect repeatedly. I am no longer responding to you in this thread. Feel free to post another extremely long post with no content, as I plan to not read it. There is plenty of evidence right in this forum that shows your complete misunderstanding of this subject that you so often reply to.

ahmadka: I would recommend you wait for other posters for discussion.

 

[westom]

I am no longer responding to you in this thread. Feel free to post another extremely long post with no content, as I plan to not read it.

You keep promising to stop posting (as you do in all threads). Then post more cheapshots. Please do something you have never done. Surprise me. Keep your word. Go away so that honest people can learn what you never did.

 

[Cerb]

So why is this so ?

The protection is provided by a device called a MOV, which is a type of variable resistor. When a surge occurs, it becomes a low-resistance path to ground ("between" would be more accurate, since it works both directions), so that the surge current passes through it, rather than your equipment connected to it. It degrades over time, eventually failing (it is sacrificial). At what voltage and amperage it will start shunting, and by how much, varies. A MOV that can handle a great deal of energy tends to also take a lot more energy, before it, "kicks in." A MOV that will kick in with smaller surges will not be able to handle massive surges, but a MOV that can handle massive surges may not protect well against smaller ones.

The online APC UPS (working link) is likely rated for the surges it can actively suppresses with its line filtering.

 

[westom]

The protection is provided by a device called a MOV, which is a type of variable resistor. When a surge occurs, it becomes a low-resistance path to ground ("between" would be more accurate, since it works both directions), so that the surge current passes through it, rather than your equipment connected to it. It degrades over time, eventually failing (it is sacrificial). At what voltage and amperage it will start shunting, and by how much, varies.

First step back to view an entire picture. A surge (lightning used in this example) is an electrical current from an above cloud to earthborne charges some miles distant. What is the path of that current? Maybe three miles down to earth and four miles through earth to those charges. If that current remains outside, then no damage. But when a best connection from cloud to earthed charges is via household appliances, then damage results.

Once that current is permitted inside, it will go hunting for earth via household appliances. If that current is incoming to an adjacent protector, it is also outgoing at the same time through the appliance to earth.

So, a surge current enters the house via an AC hot wire. Incoming to a protector on a black (hot) wire. Maybe putting 5000 volts on that wire. MOVs with a let-through voltage of maybe 330 volts means 4670 volts on the green (safety ground) and white (neutral) wires. What has the MOV done? Given that surge even more paths to find earth destructively via the appliance. Where is the protection?

Often a surge, too tiny to damage an appliance, also destroys the undersized protector. Then many consumers speculate that MOVs are sacrificial. Again, when a current was incoming to that protector, it was also outgoing into the appliance. Robust protection in an appliance made that current irrelevant. Grossly undersized MOVs in the protector failed catastrophically (sacrificially). Since the appliance protected itself, then many consumers assume a catastrophically damaged protector did protection.

MOV manufacturers are quite clear about this in datasheets. A catastrophic failure is unacceptable. Some catastrophically failed plug-in protectors have caused house fires.

Properly sized protectors have MOVs that only degrade - the acceptable failure mode. Properly sized MOVs means many direct lightning strikes over many decades. And that protector remains functional. Numbers define the difference between a tiny hundreds of thousand joules protector. Verses proven technolgy that, at 50,000 amps, will make 20,000 amp lightning irrelevant. This protector is undamaged. Energy dissiaptes harmlessly in earth. And this superior protector that can handle massive surges is also a best protector for smaller ones. Unlike power strip protectors, the 'whole house' solution is for all types of surges.

MOV protector adjacent to an appliance is for a surge typically made irrelelvant by what already does protection inside every appliance. For destructive surges, it can even give a surge additional paths that compromise protection inside an appliance. And finally, that undersized protector needs protection only provided by a 'whole house' solution.

What does a protector adjacent to an appliance not have? That low impedance (ie 'less than 10 foot') connection to earth.

To summarize, only a grossly undresized protector is sacrificial. These are not designed to absorb a destructive surge that is hundreds of thousands of joules. That surge incoming to a protector is also outgoing into attached appliances. Same current at the exact same time. Smaller surges that do not damage appliances can also destroy a grossly undersized and adjacent protector. But the proven 'whole house' protector with an always required earth ground connection is rated to conduct maybe 50,000 amps without damage. This is important because sacrificial MOVs are ineffective protection. And also a potential threat to human life (ie fire).

 

[Flapdrol1337]

I'd like to know why most (if not all) APC Smart Online UPS's have such low Surge Energy Ratings ?! Considering that these UPS's cost $2000 ~ $3000 a piece, one would expect them to have an exceptionally high Surge Energy Rating, higher than most common cheap surge protectors available in the market. But this is not so.

For example, THIS (need to click here) UPS only has a 480 Joules Surge Energy Rating, but the following cheap surge protectors offer almost 10 times the Surge protection, but cost only a fraction:

Belkin 12 Outlet Pivot Plug Surge Protector with 8 Foot Cord ~ 4320 Joules ~ $27.10

Tripp Lite HT10DBS Home Theater Isobar Surge Protector 10 Outlet RJ11 RJ45 Coax ~ 3840 Joules ~ $79.96

So why is this so ?

My guess is lower=better. The fancy one already trips after 500 Joule, the cheap ones allow 4000 Joules to pass?

 

[imagoon]

My guess is lower=better. The fancy one already trips after 500 Joule, the cheap ones allow 4000 Joules to pass?

The larger the number, the larger the amount of power the surge systems gets dissipate to what ever surge suppression system is used, be it grounding, neutral pathing, line to line, heating etc. The larger number generally indicates how beefy the MOVs are and how well they are heatsinked since they will dissipate a significant amount of heat when triggered.

 

[Cerb]

First step back to view an entire picture. A surge (lightning used in this example) is an electrical current from an above cloud to earthborne charges some miles distant. What is the path of that current? Maybe three miles down to earth and four miles through earth to those charges. If that current remains outside, then no damage. But when a best connection from cloud to earthed charges is via household appliances, then damage results.

Once that current is permitted inside, it will go hunting for earth via household appliances. If that current is incoming to an adjacent protector, it is also outgoing at the same time through the appliance to earth.

So, a surge current enters the house via an AC hot wire. Incoming to a protector on a black (hot) wire.

Not so. The surge may come from ground just as well, or from a line that isn't providing any power at all. Most I've seen have done their damage through telephone or cable. In fact, "from" and "to" are just conceptual, for our brains' benefits, and are usually backwards. A current loop is formed, and the surge happening means it has already "found" one or more paths. Those paths, if at high voltage, like lightning, can easily jump across insulated conductors, too. It's not bound for just one AC line, though if it hits your stuff, it will be traveling along ground or neutral. The best path to ground might be from your cablemodem's NIC to the cable entering the house, FI, rather than the cable's bonding near the service entrance, due to the inductance of that path, compared to a direct path to ground.

Then many consumers speculate that MOVs are sacrificial.

No, that is fact. When a MOV passes a large current, it degrades. Its electrical characteristics change, and it may get cracks. There is no way for us, or the makers of the SPDs, either, to know before-hand how a specific MOV is going to fail in a specific installation, assuming there are enough surges to cause it to, over time. There is also no assurance than a MOV with a connection between its terminals is going to be effective, if it fails by way of requiring added energy to activate. A MOV that is sized to where it won't degrade much over its service life is going to require powerful lightning strikes to activate, making it basically useless for the rest of the surges, and also only a hope and a prayer, since then the MOV will have to be the best path to ground for the strike, which is not something easily controlled.

But, MOVs like are in your surge protectors can be had for $2 or less in individual quantities, and who knows how cheap in quantities that companies like APC are buying. The protection is good considering the cost, including the now-required thermal protection for the MOV.

Every surge it shunts is one whatever connects to it doesn't have to deal with, most of which are not from lightning. When lightning strikes, all bets are off. The surge strip may protect, which is great if it does, but if it doesn't, oh well. Discharging coils, power grid circuitous re-closing, super-imposed voltage spikes from crappy SMPSes, and small surges from the sorts of conditions that create lightning strikes, are much more what they are there for, to keep your equipment working well and for a long time in normal use. Lightning-born surges may be protected by them, but if so, the surge was already protected against other factors, since working protection means it was fairly low-energy as it traveled through the home (IE, it would quickly have fried itself, and allowed the rest of the energy to go through your devices, otherwise). They may be able to protect against lightning-born surges sometimes, but that's just a nice extra when it happens. In general, you can't do much against Thor, once the building is up and wiring in place.

Verses proven technolgy that, at 50,000 amps, will make 20,000 amp lightning irrelevant.

Anything that can take 20,000 amps is likely not connected to any electrical system in your home. Most electronics will be burning up their wiring well before 100 amps. If that kind of current is being carried, things will burn, and fire will be a much greater danger than loss of some electronics.

What does a protector adjacent to an appliance not have? That low impedance (ie 'less than 10 foot') connection to earth.

An appliance doesn't usually have that, either (I've only ever seen that in the case of a washer and dryer in a garage), nor does either have what turns a path from delectable to disgusting: a low-inductance path to ground. It will take a low-impedance or high-inductance path, and if it's high-frequency, the high-inductance path will win. That path may cross conductors which are air-gapped, and may not be the path of least impedance. Keeping potential paths low-impedance helps prevent your wiring from being a good target, but once that's out of the way...

 

[Cerb]

My guess is lower=better. The fancy one already trips after 500 Joule, the cheap ones allow 4000 Joules to pass?

What if it's more than one? And that's why, basically, don't sweat it. Get one from a known brand and move on. If each plug gets its own MOV, they can add them up for the total surge current rating. This isn't a bad thing to do, since the MOVs that take lower-voltage surges tend to not take high-energy surges, at similar costs. They can act in parallel, and shunt more current, of lower voltage, with less damage per-MOV per-surge. But, it will cost them more than one big MOV, that may do hardly anything for small surges. Ultimately, you're at the mercy of the EEs that designed it, and have no real insight into their choices.

 

[westom]

If each plug gets its own MOV, they can add them up for the total surge current rating. ... They can act in parallel, and shunt more current, of lower voltage, with less damage per-MOV per-surge.

All MOVs (large and smaller) respond to large or small transient currents. No manufacturer spec numbers were posted to dispute that.

A protector adjacent to an appliance must either block or absorb that current. Surges are a current source. That means voltage increases as necessary to maintain that current flow. Any protector that would block a surge simply creates a high voltage. This is adjacent protectors can even make damage easier for at least one type of surge.

Some numbers. Assume a surge has created 5000 volts incoming on one wire. A typical MOV protector has a let-through voltage of 330 volts. Locate that number on each box for every protector. That means 5000 volts incoming on one wire. A 4670 volts incoming on other AC electric wires. Where is the protection? For this type of surge, a protector has given that surge even more potentially destructive paths.

For this type of surge, informed homeowners have installed a tens of times less expensive 'whole house' solution. Which also uses MOVs that are not sacrificial. Any protector that fails catastrophically during a surge did not do protection. Again numbers. A surge that may be hundreds of thousands of joules does what in a protector only rated for hundreds of joules? Often a surge will select one of many protectors in parallel to catastrophically destroy that one. In rare cases, a house fire may result. A problem so serious with some APC protectors that those protectors must be removed immediately.

If using a grossly undersized protector, important is to protect it with a properly earthed 'whole house' protector. This 'whole house protector typicaly costs tens or 100 tims less money per protected appliance. Facilities that cannot have damage always use a 'whole house' solution. And might even fire an employee for using those plug-in protectors.

Useful recommendations also provide those numbers. Find the let-through voltage for each protector. Also find its joules. UPSes are selling to the naive. So their protectors are near zero joules - as the OP noted.

 

[imagoon]

I would add to what Cerb said that MOVs have a designed operation time and also must be sized correctly. MOVs are used extensively in motor controls to absorb contactor arcs and well as providing a path for spin down currents in to a heat load. These units operate thousands to hundreds of thousands of times of the course of decades. They are sized to handle the load and expected wear on the part.

Basically this means the APC one could in theory have the same MOV systems as the block strip but APC has rate the system at ~460 with the expectation of 10 years of service where the strip is ~4600 joules but the part is expected to fail after a few hits of that size.

MOVs are the next logical step from the older thyrite varistors that were designed in the 1930's for power distribution surge suppression and lightning arrestation. MOVs work the same way but now have a better and steeper voltage trigger and amperage onset. Like the older tech the need to be monitored which cheap junk strips may not bother with (and as such not have the UL ratings.)

MOVs one they hit their break down voltage (conduct voltage) will only allow voltage to drift up a small amount over time. The breakdown voltage is configurable and is typically will hold line voltage to that break down voltage with in 5% (based on design specs.)

--edit--

Here is an example MOV curve:

As you can see once the break down voltage is met the voltage drifts up a small amount as current across the varistor increases. In this case a 500V surge would be shorted out and the device on output side would not see much more than the ~200V break down voltage of this device.

 

[Cerb]

For this type of surge, informed homeowners have installed a tens of times less expensive 'whole house' solution. Which also uses MOVs that are not sacrificial.

Which doesn't do anything for the surges that devices like power strips are there to protect from. If it won't significantly degrade over many surges it is rated for, it also won't be diverting the smaller surges. Devices way at the end of your wiring aren't going to be well-protected against a lightning strike that enters/exits near them, except by some other path than through them being better for the surge. Devices good enough for a lightning strike will not be doing much against lower-voltage surges. If strikes are a problem around your area, then definitely go for whole-house stuff, and if it's a recurring problem, maybe have your wiring checked out, and see what a professional recommends specifically for your area/house.

Any protector that fails catastrophically during a surge did not do protection.

Which is why they should not be left in place indefinitely, nor trusted blindly for complete protection. They provide cost-effective protection, that is now quite safe (far safer than allowing surges through to potentially cause appliance fires). One may be good in a given spot for 100 years, while another might have issues in 3 years, and aside from intentionally blowing it up under controlled circumstances, you really won't know which it was (unless it fails in just the right way to make the indicator go off). They are there to protect against the other devices on the strip just as much an anything else, and not protecting against those several-kV surges means every device has to. Some of them can, but some can't, and will have their lives shortened by those lesser surges. Likewise, the whole-house protector may not clamp soon enough for those small surges, and/or may be too physically distant to do much good, especially in places like living rooms, now full of switchers and small transformers, but without their own good ways to bleed them.

With long AC-carrying wires, nothing you add to the receptacle is going to do much good against lightning. Making those devices at the end of long wiring bad paths in the first place is going to be easier than, and do more good than, anything that can be done physically near the devices. They need to not have a good path from outside in the first place. It's not reasonable to expect a surge strip to do any good against a direct strike. Being part of the path from a nearby strike, maybe, but then that's lower energy.

Given that UL labels go into the mold whether real or not, I would want to make sure a company that could be hurt by being found faking such things, and making complete junk, is who is selling the ones I buy and use. Eaton or Tripp Lite pulling such a stunt could be as bad for them as this Lumber Liquidators thing, FI. Rosewill could shrug it off. A surge strip with faulty thermal protection, FI, could be a fire hazard in itself, or a more general health hazard, due to fumes from burning electronic parts, should it fail.

 

[Rubycon]

I suppose if you really want isolation a ferroresonant transformer or motor generator will fill the bill. (and drain the bank account!)

It's silly to expect a few parts costing less than a dollar to protect against a naturally occurring event that can turn miles of air into a good conductor!

The wiring at the premise and outside will take care of most of that. Small-ish VSPs will bring down the remnants to levels that the device's integrated solutions can handle.

Problem is close/direct strikes have so many secondary paths. Severe hits with multiple path flashovers will get into your stuff one way or another.

Unless you have the budget for an engineered solution designed to take multiple strikes/year. And do you require that sort of availability in the first place? Insurance is cheaper and you get new hardware. Just make sure your data is backed up offsite.

 

[westom]

It's silly to expect a few parts costing less than a dollar to protect against a naturally occurring event that can turn miles of air into a good conductor!

And yet that is exactly how it is done in facilities that cannot have damage such as munitions dumps and rocket launch pads.

When a protector works by absorbing or blocking a surge (ie at the appliance), then yes it is silly. But proven and effective protectors (that also costs many times less money) do something completely different.

Again, best protection for an incoming wire (ie TV coax cable) is a hardwire connected low impedance (ie 'less than 10 feet') to single point earth ground (all four words have electrical significance). When a hardwire cannot connect directly, then use a next best thing - a 'whole house' protector. When is that protector better? When it absorbs least (near zero) energy.

This 'whole house' solution is the only solution always found in every telco CO, broadcasting station. rocket launch pads, 911 Emergency Response centers, and even nuclear hardened facilities. For homeowners, a robust 'whole house' protector costs about $1 per protected appliance.

'Whole house' protectors are defined by how much current can connect to earth without failure. Since lightning is 20,000 amps, then a minimal 'whole house' protector is 50,000 amps. In virtually every case, that means the protector never fails catastrophically. It only degrades by (worst case) 10% over many decades. To dispute this, have numbers. MOV datasheets are a good place to start.

All MOV manufacturers define catastrophic (sacrificial) failure as a violation. MOV manufacturers also define degradation - the acceptable failure. Its Vb voltage varies by 10%. One manufacturer defines how to test MOVs:

The change of Vb shall be measured after the impulse listed below is applied 10,000 times continuously with the interval of ten seconds at room temperature.

How many surges? 10,000?

For most homeowners, a destructive surge occurs once every seven years. If any protector fails catastrophically (its failure light only reports catastrophic failures), then that protector was grossly undersized. If failure occurs on a 'whole house' protector, then that 50,000 amps protector must be replaced by a 100,000 amp protector. Again, recommendations must include and discuss these numbers.

Routine is to earth direct lightning strikes without damage. In most strikes to trees (according to research by the US Foresty Service), well over 95% of all struck trees have no appreciable damage. Unfortunately most use junk science reasoning. They see a rare exception. Then assume all lightning struck trees have that damage. Observation without first learning basic concepts is why urban myths and junk science live on. Direct lightinng strikes without damage was routine even 100 years ago when science defined a solution.

Meanwhile, why does a UPS have near zero joules? They are marketing to people who never learned this stuff and routinely ignore numbers. That UPS could not possibly protect from a potentially destructive surge. No low impedance connection to earth. But a near zero MOV means naive consumers will recommend it as 100% protection. That near zero MOV increass sales and profits.

 

[westom]

Devices good enough for a lightning strike will not be doing much against lower-voltage surges.

MOV datasheets were ignored. First voltage is a dependent number. IOW voltage is defined by a surge current. Explains why protectors that do serious protection are rated in amperes (ie 50,000 amps).

Take a smaller 2000 amp surge trying to blow through a 660 joule protector. Voltage across that 120 volt protector rises to well over 500 volts. Meanwhile, MOVs in a larger protector would conduct that entire current with a smaller voltage - maybe 300 volts. Well below what would damage any 120 volt appliance.

View life expectancy curves. That 2,000 amp surge destroys a 220 joule protector in two surges. That same surge current not only creates a tinier voltage. But the larger protector has a life expectancy of over 100 such surges.

A larger protector means less surge voltage and longer life expectancy - better protection - during a small surge. A superior MOV will conduct 50 times more surges without degradation or catastrophic failures for tiny surges.

Let's do same calculations for a tinier 500 amp surge - one too tiny to damage appliances. That 660 joule protector will last about 400 surges. And creates maybe 440 volts. Meanwhile that larger protector creates maybe 330 volts. And has a life expectancy of over 1 million such surges. Again, the larger protector is better for an even tinier surge.

Let's discuss destructive surges - maybe 20,000 amps. A 660 joule protector fails immediately - sacrificial. So quickly as to potentially create a fire. It creates a voltage probably exceeding 900 volts. Meanwhile a larger protector will remain functional for 30 such surges. And creates only 400 volts.

Which one is more desireable at a household appliance? Obviously a larger joule protector is superior for all types of surges - larger and smaller. Smaller protector means a much higher surge voltage and a shorter life expectancy. Inferior on both counts.

Again the point. Claims made without numbers tend to be false. No numbers is a first indication of subjective or junk science reasoning.

A much larger 'whole house' protector located at earth ground increases that better protection - for all transients large and small. Numbers come directly from MOV manufacturer datasheets.

Destructive transients do not cause fires in appliances. Appliances are more robust. A threat and resulting fire is created by undersized MOVs inside power strip protectors. Also called sacrificial protectors. Therefore these protectors should never be behind furniture, on a rug, or in some confined space. This was especially true of some APC protectors. Their new owners announced some are so dangerous as to be removed immediately. Protectors from other manufacturers (Belkin, Panamax, Tripplite, Monster, etc) are electrically similar. An informed consumer is concerned; heeds these warnings that are supported by numbers and industry history.

Above numbers apply to protectors with UL1449 listings. That threat is drastically reduced when plug-in protectors are protected by a properly earthed 'whole house' solution. Which also provides better protection for all surges - both large and small.

 

[imagoon]

It's silly to expect a few parts costing less than a dollar to protect against a naturally occurring event that can turn miles of air into a good conductor!

I think these 200ka MOVs cost a bit more than a dollar

http://ep-us.mersen.com/fileadmin/catalog/Data-Sheets/Advisor111-N-SurgeProtection-web.pdf

These are obviously overkill for most home uses. Except for direct structure strikes... maybe.

 

[Rubycon]

I think these 200ka MOVs cost a bit more than a dollar

http://ep-us.mersen.com/fileadmin/catalog/Data-Sheets/Advisor111-N-SurgeProtection-web.pdf

These are obviously overkill for most home uses. Except for direct structure strikes... maybe.

Yes but I was referring to your typical Chinese origin power strip with "protection".

 

[Subyman]

FWIW, OP is comparing apples to oranges. UPS absorbs small surges or fluctuations, a protector diverts the surge to ground. Some UPS may have higher surge protections, but they will divert to ground just like any other cheapo protector. Most residential grounds are only 12ga wire at most, running through multiple sockets, back to the electrical box and then directed to earth through a copper grounding rod. Hardly enough for adequate direct strike protection.

Best solution for such a catastrophic strike is to have off site backups and decent insurance

 

[westom]

Most residential grounds are only 12ga wire at most, running through multiple sockets, back to the electrical box and then directed to earth through a copper grounding rod. Hardly enough for adequate direct strike protection.

Meanwhile protection from direct lightning strikes does not use that safety ground. Low impedance connection to earth is not possible with solutions inside a building. Direct strike protection means that current does not even enter a building. Then protection inside each appliance (that is far superior to what a typical UPS might provide) is not overwhelmed.

Of course we are not discussing the building wide UPS ($tens of thousands) that typically does make that low impedance connetion to earth. But a standard UPS powering most computers does not provide any such protection; is for blackouts.

 

[Tsavo]

You must be looking in a mirror when you say this. You have been proven wrong for the better part of a decade and at least 25 forums where I have seen you post. My electrical engineering team even has posted some of your threads on the wall for the hilarity. Simply put, I don't consider anything you post as a valid source because it has been proven incorrect repeatedly. I am no longer responding to you in this thread. Feel free to post another extremely long post with no content, as I plan to not read it. There is plenty of evidence right in this forum that shows your complete misunderstanding of this subject that you so often reply to.

ahmadka: I would recommend you wait for other posters for discussion.

Why do people even argue with Westom? He's a 100% genuine kook that trolls forums *all over the internet* looking to appear smart, and posting long, pointless drivel that doesn't actually add anything to any discussion he participates in.

I'm not trying to slam the guy, but he's a genuine kook. He's been banned from three forums that I know of, and none of these forums have anything to do with tech, electrical issues or related topics. He literally joins hundreds of random forums looking to get into arguments with people in some weird need to appear intelligent and informed, when the reality is that he's neither.

Another really odd aspect about Westom is that he's been doing this for years and years.