Connect with us

Surge Protectors

Discussion in 'Electronic Repair' started by [email protected], May 26, 2010.

  1. Guest

    Are surge protectors based on grounding or diode clipping?




    - = -
    Vasos Panagiotopoulos, Columbia'81+, Reagan, Mozart, Pindus, BioStrategist
    http://www.panix.com/~vjp2/vasos.htm
    ---{Nothing herein constitutes advice. Everything fully disclaimed.}---
    [Homeland Security means private firearms not lazy obstructive guards]
    [Urb sprawl confounds terror] [Phooey on GUI: Windows for subprime Bimbos]
     
  2. Guest

    Thanks for both replies.


    - = -
    Vasos Panagiotopoulos, Columbia'81+, Reagan, Mozart, Pindus, BioStrategist
    http://www.panix.com/~vjp2/vasos.htm
    ---{Nothing herein constitutes advice. Everything fully disclaimed.}---
    [Homeland Security means private firearms not lazy obstructive guards]
    [Urb sprawl confounds terror] [Phooey on GUI: Windows for subprime Bimbos]
     
  3. GregS

    GregS Guest

    I would argue that. The differential surpressor is fine, but the common
    mode surge can do more harm and a lot of noise problems. Using an isolation transformer
    makes common mode problems impossible. Its a direct short to ground.

    greg
     
  4. GregS

    GregS Guest

    I thought there were NO supressors in most consumer equipment
    because its a liability.

    Its the line to ground noise and surges that cause TTL computer type equipment
    to BOMB OUT. Ground has everything to do with functioning circuits, that use ground
    for reference. Of, course, its best not to use ground for reference.

    greg
     
  5. Guest

    Well, here's is a disclosure of the biases which might be distorting my
    thinking: In February and August 2001 I lost two external modems to lightning
    (caused my line to be off-hook until disconnected modems) and someone on
    usenet told me to tie a ground to the modem. That particular computer (Ampro
    2210 80186 hooked up to 1980 HP2621a terminal) with modems had previously
    survived 1988-1995 without problems (no phone surge supressor but one on
    power). In 2008 I lost two LCD monitors the same week during light rain. I
    am therefore excessively (and probably unreasonably) cautious of using
    computers during bad weather. Also in 1980 I took two semesters of EE for
    non-EEs (am a 1981 ChE).

    - = -
    Vasos Panagiotopoulos, Columbia'81+, Reagan, Mozart, Pindus, BioStrategist
    http://www.panix.com/~vjp2/vasos.htm
    ---{Nothing herein constitutes advice. Everything fully disclaimed.}---
    [Homeland Security means private firearms not lazy obstructive guards]
    [Urb sprawl confounds terror] [Phooey on GUI: Windows for subprime Bimbos]
     
  6. Guest

    *+-even the cheap suppressors I've bought had 3 MOVs,one for each leg to
    *+-ground and from one leg to the other. I guess that's a "delta" config.

    Do surge supressors exist for two-line phone connections?

    WOuld it make sence to put a surge suppressor (what kind?) on my
    incoming phone line? Neighbors have complained of fried modems, but
    curiously I don't remember anyone ever telling mtheir computer got fried.


    - = -
    Vasos Panagiotopoulos, Columbia'81+, Reagan, Mozart, Pindus, BioStrategist
    http://www.panix.com/~vjp2/vasos.htm
    ---{Nothing herein constitutes advice. Everything fully disclaimed.}---
    [Homeland Security means private firearms not lazy obstructive guards]
    [Urb sprawl confounds terror] [Phooey on GUI: Windows for subprime Bimbos]
     
  7. This applies to the US-

    there are surge and lightning arrestors on phone lines where they enter a residence, and they're
    grounded to something good, like a water pipe for instance.

    It works great.

    Now if lightning surges hit your power then what happens?

    a cheapo-garbage "surge protector" like a power strip or the like will use MOVs to short out line
    to neutral or even line to ground.

    What happens if you throw a short across line to ground and can somehow clamp it to 600 volts or
    whatever? The numbers are made up, but concept is the same.

    well, your ground ends up at 300 volts above actual earth ground where that device is located. This
    assumes your ground has the same impedance as the current carrying conductors.

    So now your computer isn't really grounded, and floating at a potential way off what the phone like
    is at, which worst case is being protected to a really solid ground, and not hundreds of feet or
    wiring in your walls or whatever.

    This is what blows up stuff like modems or devices that sit between your outlets and a phone line.

    The best move is to install a service entrance surge supressor. They'll clamp surges at the best
    ground you've got, with the lowest possible impedance, and at your ground/nuetral bonding point not
    at your load where any attempts to do so are pretty useless across the extra fraction of an ohm.

    You can easily test the resistance of your wiring at home too, and at the same time actually test
    if your ground is solid.

    connect some large resistive loads like halogen lamps, hairdryer, toaster oven or whatever at and
    outlet. Measure the voltage drop when it's on. Break out the suicide cables and test that same
    device using line to ground.

    Depending on how your place is wired, you may find that under an actual load, your ground is really
    awful. A volt meter won't pick crappy ground connections unless you are actually running real
    current through it, so just reading 120 across hot and ground and saying "looks good" really
    doesn't count.

    Trying to suppress a surge with a $4 power strip connected though 5 junction boxes connected with
    BX cable can really just be a big joke.
     
  8. bud--

    bud-- Guest

    Some comments are somewhat specific to the US.

    A couple of excellent sources of info on surge protection are:
    <http://www.mikeholt.com/files/PDF/LightningGuide_FINALpublishedversion_May051.pdf>
    from the IEEE, and a much simpler one from the US-NIST
    <http://www.nist.gov/public_affairs/practiceguides/surgesfnl.pdf>

    With a strong surge current to the earthing electrode, the "ground" for
    the building can rise thousands of volts above "absolute" earth
    potential. You want power and phone (and cable) wires rise together.
    That requires a short ground wire from the telephone entrance protector
    to the earthing system at the power service.
    If you RTFM, any competent plug-in suppressor manufacturer should tell
    you the phone wires have to go through the suppressor along with the
    power wires. The voltage on all wires is clamped to the ground at the
    suppressor. The voltage between the wires to the protected equipment is
    safe for the protected equipment. All interconnected equipment needs to
    be connected to the same suppressor, or external wires, like cable need
    to go through the suppressor. This is clearly explained in the IEEE
    guide starting pdf page 40, and shown in the examples at the end.
    Plug-in suppressors work primarily by clamping, not earthing.
    Service panel suppressors are a real good idea. I would particularly use
    one in high risk areas like Florida.

    But from the NIST guide:
    "Q - Will a surge protector installed at the service entrance be
    sufficient for the whole house?
    A - There are two answers to than question: Yes for one-link appliances
    [electronic equipment], No for two-link appliances [equipment connected
    to power AND phone or cable or....]. Since most homes today have some
    kind of two-link appliances, the prudent answer to the question would be
    NO - but that does not mean that a surge protector installed at the
    service entrance is useless."

    The NIST guide suggests most damage results from high voltage between
    power and phone/cable wires. A service entrance suppressor does not, by
    itself, limit that voltage.
    May well be worthwhile. But even with a good earth connection the
    building ground can rise thousands of volts.
    Neither the IEEE or NIST agree. Both guides say plug-in suppressors,
    used correctly, are effective. Plug-in suppressors with very high
    ratings are readily and cheaply available. In the US you should only buy
    suppressors listed under UL1449. UL tests include a testing to at least
    a minimum floor of protection. UPSs with surge protection should also
    have UL1449 listing.

    ==========
    If there is a strong surge on power wires, with no power service
    suppressor, at about 6kV there is arc-over from the hot busbars to the
    service panel enclosure. After the arc is established, the arc voltage
    is hundreds of volts. Since the enclosure is connected to
    ground-neutral-earthing electrode, most of the surge energy is dumped to
    earth. A surge is a short event, thus a relatively high frequency event.
    The impedance of the branch circuit greatly limits the current to a
    plug-in suppressor (unless the branch circuit is very short) and thus
    limits the energy that can reach a plug-in suppressor. For both these
    reasons the energy dissipated in a plug-in suppressor is surprisingly small.

    Neither service entrance or plug-in suppressors work by absorbing the
    surge energy. But in the process of protecting, some energy is absorbed.
     
  9. The lab NIST uses is not the typical home people live in.

    Have you opened a "surge supressor" that the average person owns? It's
    really surprising more don't catch on fire with no surges.

    the construction quality tends to really really suck.

    Even "name brand" items from tripp-lite are utter pieces of crap for the
    most part. I've seen those catch fire, and these were made in USA ones.

    I don't use or trust cheap-o power strips, at all, anywhere.
     
  10. bud--

    bud-- Guest

    I have no idea what you are talking about. The discussion is ordinary
    surge suppressors
    So don't get "cheap-o power strips". I use name brand suppressors with
    high ratings.

    UL1449 has, since 1998, required thermal discoinnects for overheating
    MOVs. If a suppressor is UL1449 listed there is not much probability of
    any problem. The author of the NIST guide has written "In fact, the
    major cause of [surge suppressor] failures is a temporary overvoltage,
    rather than an unusually large surge". TOV is, for example, a
    distribution wire falling onto the secondary wires that go to your house.
     
  11. yes, ordinary surge surpressors. go to the store, pick one up and tell me
    what you find inside of it.

    I'd be pleased to counter with the CPSC recall notice.
    Again, if you really trust any UL markings on a power strip, go for it.

    You do relized that UL doesn't even test most stuff, they sell stickers.
    That's the business model. If you want to get more technical, they're
    really a licensing company.

    they have nothing at all to do with safety, at all, any more than iso 9001
    has anything to do with quality.

    It's possible you have some decent surge protectors, but you're 0.01% of
    the market.
     
  12. bud--

    bud-- Guest

    Complete nonsense.

    In Europe equipment is mostly self-certified that it meets a standard.

    UL tests almost all equipment it lists.
    http://en.wikipedia.org/wiki/Underwriters_Laboratories
    "the UL Mark requires independent third-party certification from UL"

    Some equipment, like TVs are tested to fail safely - it is not practical
    to test whether they work.

    Much of the UL listed equipment - fuses, circuit breakers, switches, ...
    - are tested to comply with a standard that requires “fitness for a
    given use” and “service life”.Ordinary wall switches used in power
    wiring are tested by UL to remain functional after 30,000 operations at
    or above their current and voltage rating. (The test is a lot more
    involved than that.)

    For surge suppressors, under UL1449 suppressors are tested by UL for
    let-through voltage under specified conditions followed by a series of
    20 surges followed by a let-through voltage test again. If the second
    let-through voltage dropped significantly the MOVs are deteriorating. A
    suppressor has to be functional through all these tests. Further tests
    are of a nature that the suppressor might fail. It must fail safely. As
    in my last post, overheating MOVs must be disconnected safely.

    Incidentally, I was the technical end of a UL panel shop.
    UL listing of electrical equipment has everything to do with safety.
    UL1449 listed suppressors have been tested to pass at least a minimum
    floor of protection. Anyone can buy well known name brands and get
    suppressors with high ratings like I do.

    Francois Martzloff was the surge expert at the US-NIST and wrote the
    NIST guide. He also has many published papers on surges. I have included
    some of his information in previous posts.

    In one of his papers Martzloff has written "in fact, the major cause of
    [surge suppressor] failures is a temporary overvoltage, rather than an
    unusually large surge". TOV is, for instance, a distribution wire
    dropping onto the wires that go to your house. (This is, of course, not
    a surge.)

    Martzloff also suggests in the NIST guide that most equipment damage is
    from high voltage between power and cable/phone wires. (This is
    illustrated in the IEEE guide starting pdf page 40.)

    The IEEE is the largest association of electrical and electronic
    engineers in the US. The IEEE guide (a link was provided) was written by
    the IEEE committee that covers surge protection devices. The IEEE guide
    says plug-in suppressors are effective. The only 2 examples of
    protection in the IEEE guide use plug-in suppressors.

    Similarly, surge expert Martzloff says in the NIST guide (link provided)
    that plug-in suppressors are effective.

    Where is your source that says otherwise.
     
  13. So, did martzloff test this item?

    http://cpsc.gov/cpscpub/prerel/prhtml10/10184.html

    what about this, who tested these? they were wired with reverse polarity,
    even a $3 outlet tester would have found that:

    http://cpsc.gov/cpscpub/prerel/prhtml04/04573.html

    how about energizer branded products, were these tested:

    http://cpsc.gov/cpscpub/prerel/prhtml04/04002.html

    That's just a random sampling. These products and pretty much anything
    similar are the most poorly constructed and designed products ever made,
    next to coffee pots that lack power switches.

    If you really expect some item that's about to burst into flames by just
    being plugged in to protect anything when there's a power surge, you must
    love living on the edge.
     
  14. bud--

    bud-- Guest

    The recall is for a power strip, which is not a surge suppressor.

    It was tested by ETL - maybe a reason to not buy equipment that is not
    tested by UL. Did ETL use the appropriate UL standard?
    Wow - a recall from 2004.
    It also does not cover any surge related components. So what? Companies
    can make dumb mistakes.
    How devastating - a recall from 2003. Appears to be UPS parts, not surge
    related parts.

    The pictures of the case shows no UL label - a label should be visible.
    Anecdotal evidence proves astrology and homeopathy work.
    I understand now. You are afraid of electricity. Avoid the nasty
    electrical stuff - *any* of which may be recalled. Just move to the
    country, use candles and outhouse and a horse. Maybe you could become Amish.
    I don't expect any listed surge suppressor to burst into flames so I
    guess I am not living on the edge.

    UL listed suppressors made since 1998 have thermal disconnects to
    disconnect overheating MOVs.

    None of your horrifying links have anything to do with surge protection.

    The 6 electrical engineers who actually know something about surge
    protection and who have written 2 guides all say plug-in suppressors are
    effective. They don't share your paranoia (but they aren't afraid of
    electricity).

    Where is your source that says plug-in suppressors are not effective?

    And why does the IEEE guide use plug-in suppressors in the only 2
    examples of surge protection?
     
  15. bud--

    bud-- Guest

    westom (aka w_tom) is a well known internet nut on a religious crusade
    to eliminate the scourge of plug-in suppressors. He is here because he
    uses google groups to look for "surge".

    As I said previously (and westom conveniently did not include), UL
    requires that suppressors - plug-in and service panel - be fully
    functional after a series of 20 test surges. They can fail only during
    later tests that determine they fail safely.

    So does a suppressor have to be working after *all* the tests? No. The
    later tests are intended to cause failure.

    Does it have to successfully suppress the test surges and remain fully
    functional? Yes.
    In westom's mind plug-in suppressors have minuscule ratings and service
    panel suppressors have mega-ratings.

    In fact:
    - UL listed suppressors have been tested to provide at least a floor
    level of protection.
    - As I said previously, the amount of energy absorbed in a MOV in a
    plug-in suppressor is surprisingly small, even with a very strong strike
    to a utility pole behind a house (information from Martzloff technical
    papers).
    - Plug-in suppressors with very high ratings are readily and cheaply
    available.

    UL standards are constantly changing. Where is the massive record of
    house fires?
    westom's objection to plug-in suppressors is really based on his belief
    that all protection must directly involve earthing the surge. Since
    plug-in suppressors protect primarily by clamping, not earthing, westom
    cannot figure out how they work. Perhaps because his earthing belief
    makes him look like even more of a nut, it is almost nonexistent in this
    thread.
    What does Martzloff really say about plug-in suppressors?
    Read what he wrote in the NIST surge guide:
    They are "the easiest solution".
    And "one effective solution is to have the consumer install" a multiport
    plug-in suppressor.
    If poor westom could only read and think he could discover what the IEEE
    surge guide says in this example:

    - A plug-in suppressor protects the TV connected to it.
    - "To protect TV2, a second multiport protector located at TV2 is required."
    - In the example a surge comes in on a cable service with the ground
    wire from cable entry ground block to the ground at the power service
    that is far too long. In that case the IEEE guide says "the only
    effective way of protecting the equipment is to use a multiport
    [plug-in] protector."
    - westom's favored power service suppressor would provide absolutely NO
    protection.

    It is simply a lie that the plug-in suppressor in the IEEE example
    damages the second TV.
    westom forgets to mention that Martzloff said in the same paper:
    "Mitigation of the threat can take many forms. One solution illustrated
    in this paper, is the insertion of a properly designed [multiport
    plug-in surge suppressor]."

    At the time of the paper, 1994, multiport surge suppressors (including
    ports for phone and cable) were just a concept or very new. The whole
    point of his paper was that multiport suppressors were effective
    protecting, for example, TVs with both power and cable connection.

    On alt.engineering.electrical, westom similarly misconstrued the views
    of Arshad Mansoor, a Martzloff coauthor, and provoked a response from an
    electrical engineer:
    "I found it particularly funny that he mentioned a paper by Dr. Mansoor.
    I can assure you that he supports the use of [multiport] plug-in
    protectors. Heck, he just sits down the hall from me. LOL."

    Trying to twist sources to say the opposite of what they really say is a
    favorite tactic.
    A service panel suppressor is a good idea.
    But again quoting from NIST surge guide:
    "Q - Will a surge protector installed at the service entrance be
    sufficient for the whole house?
    A - There are two answers to than question: Yes for one-link appliances
    [electronic equipment], No for two-link appliances [equipment connected
    to power AND phone or cable or....]. Since most homes today have some
    kind of two-link appliances, the prudent answer to the question would be
    NO - but that does not mean that a surge protector installed at the
    service entrance is useless."

    A service panel suppressor does not limit the voltage between power and
    cable/phone wires, which the NIST surge guide suggests is the cause of
    most equipment damage.


    For real science read the IEEE and NIST guides to surge protection. Both
    say plug-in suppressors are effective.

    Then read the sources that agree with westom that plug-in suppressors
    are NOT effective - there are none.

    Simple questions that have never been answered:
    - Why do the only 2 examples of protection in the IEEE guide use plug-in
    suppressors?
    - Why does the NIST guide says plug-in suppressors are "the easiest
    solution"?
    - Why does the NIST guide say "One effective solution is to have the
    consumer install" a multiport plug-in suppressor?
    - How would a service panel suppressor provide any protection in the
    IEEE example, page 42?
    - Why does the IEEE guide say for distant service points "the only
    effective way of protecting the equipment is to use a multiport
    [plug-in] protector"?
    - Why did Martzloff say in his paper "One solution. illustrated in this
    paper, is the insertion of a properly designed [multiport plug-in surge
    suppressor]"?
    - Why does Dr. Mansoor support multiport plug-in suppressors?
     
  16. GregS

    GregS Guest


    I have been thinking of putting a main surpressor in the breaker box.
    When I moved in the power company said there was one
    installed in the meter, and if I wanted to continue using
    it it would cost so much per month. i didn't of course, but I wonder
    if they really took it out. ??

    I put a couple in in the old house on the telephone lines
    to ground on the main wooden panel after I destroyed a modem.
    Never had any know hits after that though.

    just last week guy here said his surge surpressor exploded as a hit
    happened outside the house. His TV still works.


    greg
     
  17. bud--

    bud-- Guest

    The utility suppressors I have seen are between the meter and meter box
    - there is a spacer between them.

    I would rather have my own service panel suppressor. The IEEE surge
    guide has advice for ratings and installation.

    They solve many, but not all, surge problems. They are a particularly
    good idea in high lightning areas.
    As I have said several times, the NIST surge guide suggests that most
    equipment damage is likely caused by high voltage between power and
    phone/cable wires.

    In the US, telephone companies are almost always very good about
    installing an entrance protector that clamps the voltage on the phone
    wires to a ground terminal. The ground terminal needs to connect with a
    short wire to the ground at the electrical service. With a large surge
    the house ground can rise thousands of volts above absolute ground. You
    want all wiring - power, phone, cable, satellite - to rise together.
    This is stressed in the IEEE surge protection guide - very good
    information. A cable entry ground block also has to connect with a short
    wire - cable companies are not nearly as good as phone companies doing
    this right. And satellite entry ground blocks also have to connect to
    the power grounding system. Satellite installations can be even worse.

    As I said previously, if you use a plug-in suppressor all external wires
    to a set of protected equipment need to go through the suppressor -
    power, phone, cable, .... This prevents high voltage between the wires
    to the protected equipment.
     
  18. GregS

    GregS Guest

    I have to recheck my cable for ground. I still have a telephone to the house unused,
    and an old unused Comcast phone box unused. Also the battery power
    supply backup which I am going to use for my house emergency
    lighting.

    I just checked, and its difficult to find surpressors that are cheap.
    I found one for $30 and might get a discounted price.
    This is a basic model..................
    http://www.grainger.com/Grainger/items/1ECD1?Pid=search

    greg
     
  19. GregS

    GregS Guest

     
Ask a Question
Want to reply to this thread or ask your own question?
You'll need to choose a username for the site, which only take a couple of moments (here). After that, you can post your question and our members will help you out.
Electronics Point Logo
Continue to site
Quote of the day

-