surge protectors in series

Discussion in 'General Electronics Chat' started by electronis whiz, Jul 1, 2013.

  1. electronis whiz

    Thread Starter Well-Known Member

    Jul 29, 2010
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    does plugging surge suppressors into each other provide more protection? first one would pick up most of them then if bigger or first failed then think others would be beneficial. is my theory correct or is this pointless?
    I feel makes since because generally use varistors sends spikes to ground and stacking them would add more capacity to absorb the surge because more varistors.
     
  2. vk6zgo

    Active Member

    Jul 21, 2012
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    If you plug surge suppressors one into the other,they are not "in series".

    The correct term,which seems to have fallen into disuse,is "in cascade".

    Depending on the circuitry,some components may end up being in series,whilst others,such as the varistors you spoke of,will be in parallel.

    That said,I'm not quite sure if it would be that beneficial,but if wouldn't do any harm.
     
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  3. westom

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    Nov 25, 2009
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    First, daisy chaining power strips is a human safety threat.

    Second, you have assumed protectors work by absorbing surges. They do. And then view the numbers. A destructive surge is typically hundreds of thousands of joules. The protector is how many joules? Hundreds? So how many power strips will you daisy chain for hundreds of thousands of joules?

    Third, to connect that energy to earth means the protector must be located within feet of earth ground. Two completely different devices unfortunately have the same name. That adjacent power strip does not even claim to protect from typically destructive surges. And is often grossly undersized to fail.

    The other (effective) device always has a low impedance (ie 'less than 10 foot') connection to earth. Protects from all types of surges. Protects everything in the house. And does not fail even due to a direct lightning strike.

    So what do you want? A power strip that in rare cases can even create a house fire? Or surge protection? A superior solution costs about $1 per protected appliance. And need not create that human safety threat.
     
  4. electronis whiz

    Thread Starter Well-Known Member

    Jul 29, 2010
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    ok.
    I was referring to like the wallwort type suppressors and UPS. I currently have my PC on 3 a ups into another UPS then that plugs in a wallwort surge protector.
     
  5. westom

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    Nov 25, 2009
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    So are you daisy chaining power strips? Essential for some protection from fire: does each have, at minimum, a 15 amp circuit breaker?

    Second, you have assumed those devices work by absorbing surges. View the spec numbers. A destructive surge is typically hundreds of thousands of joules. How many joules does it claims to absorb?

    Third, that adjacent power strip or UPS does not even claim to protect from typically destructive surges. Or do you have manufacturer specification numbers that claim that protection?

    What do you want to avert? Which anomaly does it claim to address in specifications? And which ones do you wish to address?

    A new question. If a PC needs protection, then why ignore the furnace, refrigerator, radios, air conditioner, charging mobile phones, bathroom GFCIs, clocks, dish washer, dimmer switches, TV, CFL light bulbs, and most important - smoke detectors? Why spend many times more money to only protect a PC? And from what? Which electrical anomaly concerns you?
     
  6. electronis whiz

    Thread Starter Well-Known Member

    Jul 29, 2010
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    I never really looked at specs other than VA for ups. one ups I bought the suppressor, other ups were just given to me during a maintenance procedure where ups were upgraded. It appears the UPSs have about 10A breakers.
    only thing else I would even be worried about would be my AV setup, but that's all pretty old devices, and got in a suppressor/power strip.
     
  7. westom

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    Nov 25, 2009
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    What does it do? Temporary and 'dirty' power during a blackout. A typical UPS does not claim other useful functions.

    Even the expression 'pure sine wave' is subjective: how to sell to the naive. My 'pure sine wave' UPS looks much like this picture provided by an AC utility:
    http://www.duke-energy.com/indiana-business/products/power-quality/tech-tip-03.asp

    Well, that is a pure sine wave output. 'Dirtiest' power is a sum of pure sine waves. And a reason why some UPS manufacturers quietly recommend no power strip protectors on their UPS output. A perfect example of lies or deception legally created using subjective reasoning.

    What anomaly is to be solved? That question must be answered before implementing a solution.
     
  8. electronis whiz

    Thread Starter Well-Known Member

    Jul 29, 2010
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    I'd just like to fix normal surges from utility issues, and possible issues fro storms. I know that a direct hit near by to a line or building nothing will probably stop.
    we are about 15 mi from the nearest city, and are the last house on the line that's on our road. I feel this adds a good bit more risk of issues because so much area for issues. also have a friend that told me he had another friend that was in a similar situation to us and he had things getting toasted every few years because length of run and being on end of line.
    my logic for the setup was that the $3 wallwort would help save my $40 UPS should we get any surges. and hopefully lower some, but also leave some so the ups would realize it and would switch to battery.
     
  9. studiot

    AAC Fanatic!

    Nov 9, 2007
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    Varistors and other devices are sacrificial in operation. That means that they are often destroyed in the process of (surge) protection and are only guaranteed for a 'single use.'

    However, in my experience surges fall into two types.

    1) Dramatic surges of the type you and westom have been discussing. These will definitely make any protection device single use.

    2) The more common overvoltage on the mains maybe 5 - 25 volts above nominal maximum. I have a client next to a factory that shuts at 4.30pm. When they suddenly shut off all their machinery there is such a surge on the local mains (ie every day). This has taken out commercial catering equipment after repeated occurrence, but the IT network protection (UPS) survived as did the network, which suffered various damage before I installed the protection.

    Ordinary 'protectors' of the type you describe survive, but offer little protection against this type of surge.

    You can get a measurable surge on your own mains if you have say a large freezer or motor or a/c unit between your sensitive equipment and the supply.
     
    Last edited: Jul 4, 2013
  10. GopherT

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  11. westom

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    Nov 25, 2009
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    And the article got it wrong.
    Let's add what was missing. The numbers.

    How much surge current can flow through an 18 AWG (lamp cord) wire before it gets that hot? 61,000 amps. Wire inside power strips are significantly thicker. Protector fires are not due to wires burning. Fire is a protector with grossly undersized parts. One shot devices.

    A typically destructive surge is hundreds of thousands of joules. Grossly undersized (and expensive) protectors are maybe hundreds of joules. Undersized to be one shot devices. If grossly undersized and fails, then naive consumers will recommend it and buy more.

    Effective protection means direct lightning strikes do not cause damage; do not even damage a protector. A protector that fails is undersized and a potential house fire.

    A surge is electricity. If current is incoming from AC mains, then current is simultaneously outgoing into the attached appliance. A surge, too tiny to overwhelm protection already inside appliances, may damage a protector. So protector circuits must disconnect as fast as possible. Leaving a surge still connected to an appliance. As described in your citation:
    Sometimes a thermal fuse does not disconnect fast enough. Wires do not burn. Instead the MOV causes a fire. MOV operated in conditions that even violate MOV manufacturer specifications (more numbers). Power strip protector fires are rare but catastrophic. Because the protector was undersized - increased profits and to be recommended by failing.

    An example by Norma in "The Power Outage":
    No protector must throw sparks. It was grossly undersized. And did not disconnect MOVs fast enough. Many are only a $3 power strip with $0.10 protector parts to sell for $30 or $80. Profit centers; not effective protectors.

    Another example on Prang St in Boston:
    http://www3.cw56.com/news/articles/local/BO63312/

    A fire marshall describes why undersized protectors cause fires:
    http://www.esdjournal.com/techpapr/Pharr/INVESTIGATING SURGE SUPPRESSOR FIRES.doc
    Grossly undersized MOV did not disconnect fast enough. A fire resulted. Of course, protection was near zero.

    Normal surges are typically noise. How often does a refrigerator generated surge cause clock and dimmer switch damage? Obviously never because you are not replacing them daily. 'Noise' made irrelevant by protection inside electronics. Same protection also makes 'dirty' UPS power ideal and non-destructive. OP's concern is a rare surge (maybe once every seven years) that can overwhelm appliance protection.

    Two completely different devices are both called protectors. The OP knows people who need a second, different, superior, and less expensive solution. Just because all are called "surge protectors" does not mean all are same. Even a power strip protector needs protection provided by the other device - with a same name.

    Lightning is typically 20,000 amps. Please always grasp each number. Numbers are essential to understanding the solution. Another and typically effective protector has manufacturer specifications at least 50,000 amps. Because the effective protector must even earth a direct lightning strike. And remain functional.

    Effective protectors are never 'one shot' solutions. 'One shot' protectors are profit centers; not effective protection. An effective protector does not fail. And is also not a fire risk.

    Introduced are two completely different devices that share a same name. One is promoted by advertising, hearsay, and speculation. Does not claim to protect from destructive surges. And must disconnect from such surges as fast as possible to avert a fire.

    The other 'whole house' solution remains functional even after a direct lightning strike. Protects everything inside the building. Protects from all types of surges. So that nobody even knew a surge existed. This second solution is the only solution found in facilities that cannot have damage. And is desperately needed by the OP's friends.

    Next post will describe another and completely different solution. But first underlying concepts (as first taught in elementary school science) must be reintroduced.
     
    Last edited: Jul 4, 2013
  12. westom

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    Nov 25, 2009
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    Lightning seeks earth ground. A path for a 20,000 amp electric surge is via a wooden church steeple destructively to earth. Wood is not a good conductor. So 20,000 amps creates a high voltage. 20,000 amps times a high voltage is high energy. Church steeple damaged.

    Franklin installed a lightning rod. Now 20,000 amps is via a wire to an earthing electrode. High current creates near zero voltage. 20,000 amps times a near zero voltage is near zero energy. Nothing damaged.

    Lightning seeks earth ground. A lightning strike to utility wires far down the street is a direct strike incoming to every household appliance destructively to earth. Appliances are not a good conductor. So lightning creates a high voltage. Lightning current times a high voltage is high energy. Appliances damaged.

    For over 100 years, facilities that cannot have damage installed superior earthing connected low impedance (ie 'less than 10 feet') via one 'whole house' protector. Then high current creates near zero voltage. 20,000 amps times a near zero voltage is near zero energy. No appliance is damaged.

    If one appliance needs protection, then protection is also required for the furnace, refrigerator, door bell, dimmer switches, GFCIs/RCDs, clocks, air conditioner, dish washer, and smoke detectors. Spend $thousands for protectors on every (to only do what is already done inside the appliance). Or earth one 'whole house' protector to protect from the other and typically destructive type of surge.

    Some protection systems do not even have a protector. But every protection 'system' always has what does the protection. What harmlessly absorbs hundreds of thousands of joules? To protect a building, earth energy harmlessly via a lightning rod. To protect all appliances, earth hundreds of thousands of joules harmlessly via a wire or 'whole house' protector.

    No protector does protection. Either a surge harmlessly connects to earth via a wire. Or we do the next best thing. Earth a 'whole house' protector (at least 50,000 amps). Effective protectors only do what a wire would do better. And typically cost about $1 per protected appliance. Superior solution also costs less money - is not a profit center.

    Responsible manufacturers provide these superior solutions including Siemens, Intermatic, Ditek, General Electric, ABB, Polyphaser, Syscom, Clipsal, Square D, and Leviton. A Cutler-Hammer solution sold in Lowes and Home Depot for less than $50.

    Described is protection for a structure. And protection for appliances. Lightning rods and protectors are simple science. The 'art' actually does protection - earth ground. This 'art' even explains why a house at the 'end of the line' may suffer frequent damage. Effective protection means most questions are about that 'art' - how to earth and how to connect to 'single point earth ground'. All four words are electrically significant.

    Above is a major difference from what many were taught by hearsay and advertising - subjectively (no numbers). And how direct lightning strikes caused no damage - even 100 years ago. A lightning rod or protector is only as effective as its earth ground.
     
    Last edited: Jul 4, 2013
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  13. electronis whiz

    Thread Starter Well-Known Member

    Jul 29, 2010
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    I remembered in here too part of other reason I put them in. was because my computer is on a circuit with 2 freezers, lights, etc. a hole house system seems to be the way to go maybe in future I'll consider doing something like that.
    this also made me think of something else I have an old power conditioner I was given too. can those be used as surge suppressors?
    all the suppressors I use I make sure have some form of indicator light that indicates if suppressor system is functional. if that goes out then I know not to trust it and should probably pitch it.
    also out of curiosity what type suppressor is better varistors ones or tube discharge ones?
     
  14. studiot

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    Why do you think such devices are not installed as standard parts of the wiring?

    Did you read my post#9?
     
  15. westom

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    Nov 25, 2009
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    Protector failures that conform to manufacturer specs are not and cannot be reported by those indicator lights. The indicator light only report one type of failure - because the protector was grossly undersized. That light reports the thermal fuse (the emergency backup protection system) tripped to avert a fire.

    Let's view the word "surge". A surge detected by a motor home protector can be low voltage. That is completely different from a surge reported by a USB port (overcurrent). Different from a surge reported by Asus motherboards (low voltage). Different from a surge that occurs when an AC utility restores power - a slowly rising voltage.

    What does the term "power conditioner" mean? The term is subjective. Therefore says little. What anomaly does it claim to condition? Frequency variation, EMI/EMC, power factor, open neutral, RFI, sag, harmonics, blackout, etc? Different power conditioners exist for each. And have little in common. What does your power condition say it does - in manufacturer specification numbers?

    Each protector device has different parameters. Varistors will conduct most current per dollar. Also have excessive capacitance. GDTs have less live expectancy and are ideal for high frequency operation. Semiconductors (ie transorb, transil, sidactor, etc) have various configurations for a lower let-through voltage, clamping, or for use on high frequency operations (ie phones). Some semiconductor protectors work by remaining shorted when failed. Making protector failure easy to locate.

    For AC electric, varistors have been the preferred choice. For telco protection, GDTs have been replaced by semiconductor solutions.

    But again, you are asking about simple science. Not asking about the 'art'. For example, a ground wire inside a metallic conduit means compromised protection. 'Single point earth ground' and how it gets connected should be the majority of your questions. Protectors (or line conditioners) do not do protection. Hard is to unlearn what advertising preaches - a magic box. Earth ground does the protection.
     
  16. westom

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    Nov 25, 2009
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    Because code is only about human safety. This discussion is about something completely different - transistor safety.

    Sacrificial protector parts are unsized and ineffective. Described in your commercial environment is a switching transient. Those are typically another type of surge - similar to lightning. Described was the solution for all types of transients including your commercial environment. Earthing may also be insufficient. Only meet code. A protector is simple science. Earthing is an art. Earthing must exceed code.

    Common transients are not 5 or 25 volts. Read the manufacturer spec numbers for protectors. A 120 volt protector typically has a let-through voltage of 330 volts. That means the protector does nothing until voltage well exceeds 330 volts. Grossly undersized protectors can be at 900 volts when they fail. 5 to 25 volts is irrelevant due to internal protection required by international design standards long before the original IBM PC existed.

    Also stop thinking in terms of voltage. Destructive transients are current sources; not voltage sources. Voltage is a symptom. Solutions are always implemented in terms of current. And so a parameter for a 'whole house' protector - 50,000 amps minimum.

    Again the basic concepts in post 12. 20,000 amps must flow with near zero voltage. Voltage only exists when a defective solution was not designed in terms of current. And that includes shorter (not thicker) wires to ground. Voltage only increases as necessary to blow though anything that might stop or block that current.
     
  17. electronis whiz

    Thread Starter Well-Known Member

    Jul 29, 2010
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    I did I figured whole house systems were gas discharge and lasted over many activations, but the post after this says that those also wear out similarly.

    the power conditioner I was talking about I believe is supposed to compensate for surges and sags by changing windings on an isolation transformer. the unit appears to be from around 1985, the company is now gone so hard to get any info on it. made by RTE deltec. I believe input fuse is rate4d like 9-10A.

    I'm seeing how important that good grounding is incredibly important which the house I'm currently in has no ground system. all wired with 3 prong 3C romex, but outside has no ground cable or post.

    I saw in that link from the Canadian labor dept. they say this:
    Do not plug a surge protector or power strips into an existing surge protector or power strips. This practice is called “daisy chaining” or “piggy backing” and can lead to serious problems.
    not sure why they say that other than more risk of overloading.
     
  18. westom

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    Nov 25, 2009
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    It could use mechanical switching. Or, more likely, is a ferroreasonant transformer. Adjusts voltages when a specific current is maintained.

    Meanwhile, ideal voltage for all electronics is even when lights dim to 50% intensity. Are your voltages varying that much? If not, then why are voltage variations a concern?

    Motorized appliances are at greater risk. So a utility maintains voltage within tight parameters. Or disconnect power (a blackout) to protect motorized appliances.

    A safety ground (ie third prong in wall receptacles) is electrically different from the relevant ground - earth ground. Earth ground is required by code for human safety. Upgrade it for transistor safety (ie 'less than 3 meter' connection).

    In one venue, a neutral wire failed. Their earth ground was also missing. So electricity used the gas meter as a neutral wire. Fortunately nobody was home when gaskets failed and the house exploded. Another reason why earth ground is essential to human safety.

    A 'whole house' protector is only secondary protection. Also be concerned for what defines the 'primary' protection layer. A picture demonstrates what to inspect:
    http://www.tvtower.com/fpl.html

    However that is for a different anomaly - transient currents. Do light bulbs report significant voltage variations?
     
  19. studiot

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    They are not standard because they would always present a maintenance and replacement problem.
    So far as I am aware no one systematically goes round after a lightning storm and systematically checks and replaces failed protection devices in telephone circuits, where they have been fitted as standard for decades.

    @westom.

    I can see you are evangelical about the subject of protection, but please control this mixture of fact and fiction you are offering.

    electronicswizz is trying to elicit some useful advice here.
     
  20. westom

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    Nov 25, 2009
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    For telephones, spark gaps were replaced by GDTs. GDTs were replaced by a device affectionally called 'the carbons'. Those, in turn, were obsoleted by semiconductor devices. In every case, newer technology features even longer life expectancy. Withstands more surges without degradation (degradation; not catastrophic failure).

    A first indication of 'knowledge from advertising' is the mythical claim that a protector is a sacrificial device. Not true even 100 years ago. A failed protector means protection was ineffective and undersized. In some cases, even a potential house fire.

    Assuming he wants surge protection, then that means a hardwire or a 'whole house' protector connected low impedance (ie 'less than 3 meters', no sharp wire bends, etc) to what actually does protection. Single point earth ground.
     
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