OT: Lightning surges

Discussion in 'rec.audio.pro' started by Jay Levitt, Aug 5, 2003.

  1. Jay Levitt

    Jay Levitt Guest

    This is nothing to do with audio, but since there are plenty of people
    here who know about electricity...

    Twice this summer, I've lost equipment during a thunderstorm. Last
    week, I got a surge bad enough to not only fry my garage door opener but
    shatter the bulb! I have whole-house protectors at the service entrance
    (Cutler-Hammer CHSP 3-way), and some equipment is on power-strip surge
    protectors as well. All of these protectors still have their
    "protected" light lit. A few breakers did trip, which is odd - as I
    understand it, most surges are too short to trip a breaker.

    The power company wasn't aware of any strikes in my area. Is it
    possible for a nearby ground strike to somehow induce a surge in my
    power lines, bypassing the surge protectors?

    --
    Jay Levitt |
    Wellesley, MA | Hi!
    Faster: jay at jay dot eff-em | Where are we going?
    http://www.jay.fm | Why am I in this handbasket?
  2. Scott Dorsey

    Scott Dorsey Guest

    Jay Levitt <jay+news@jay.fm> wrote:
    >
    >Twice this summer, I've lost equipment during a thunderstorm. Last
    >week, I got a surge bad enough to not only fry my garage door opener but
    >shatter the bulb! I have whole-house protectors at the service entrance
    >(Cutler-Hammer CHSP 3-way), and some equipment is on power-strip surge
    >protectors as well. All of these protectors still have their
    >"protected" light lit. A few breakers did trip, which is odd - as I
    >understand it, most surges are too short to trip a breaker.


    Is your service entrance ground good?

    >The power company wasn't aware of any strikes in my area. Is it
    >possible for a nearby ground strike to somehow induce a surge in my
    >power lines, bypassing the surge protectors?


    Yes, that usually winds up polluting the ground, though, rather than
    "bypassing" the surge protectors. Remember this is really fast risetime
    stuff, so it can propagate around like radio waves.
    --scott

    --
    "C'est un Nagra. C'est suisse, et tres, tres precis."
  3. Jay Levitt wrote:

    > This is nothing to do with audio, but since there are plenty of people
    > here who know about electricity...
    >
    > Twice this summer, I've lost equipment during a thunderstorm. Last
    > week, I got a surge bad enough to not only fry my garage door opener but
    > shatter the bulb! I have whole-house protectors at the service entrance
    > (Cutler-Hammer CHSP 3-way), and some equipment is on power-strip surge
    > protectors as well. All of these protectors still have their
    > "protected" light lit. A few breakers did trip, which is odd - as I
    > understand it, most surges are too short to trip a breaker.


    Under $50 for an LA302 http://www.deltala.com/ will dissipate most of
    the problems.
  4. Jay Levitt

    Jay Levitt Guest

    In article <1060118808.696787@nnrp2.phx1.gblx.net>, kurt@nv.net says...
    > Under $50 for an LA302 http://www.deltala.com/ will dissipate most of
    > the problems.


    Is this actually an improvement over a whole-house surge suppressors?
    Cutler-Hammer sells both suppressors and arrestors; they call their
    suppressors "best" protection, while they call their arrestors "good".
    I'm a software guy, so any explanation or pointers would be helpful... I
    can find surprisingly little info via Google.

    --
    Jay Levitt |
    Wellesley, MA | Hi!
    Faster: jay at jay dot eff-em | Where are we going?
    http://www.jay.fm | Why am I in this handbasket?
  5. Jay Levitt

    Jay Levitt Guest

    In article <bgovp6$nqs$1@panix2.panix.com>, kludge@panix.com says...
    > Is your service entrance ground good?


    It *should* be, in that the whole house was rewired in 2001 to then-
    current Massachusetts code, and the electrical inspector for Wellesley
    is a bit of a stickler, and made us go farther than code in a few
    places. How can I check?

    --
    Jay Levitt |
    Wellesley, MA | Hi!
    Faster: jay at jay dot eff-em | Where are we going?
    http://www.jay.fm | Why am I in this handbasket?
  6. Dale Farmer

    Dale Farmer Guest

    Jay Levitt wrote:

    > This is nothing to do with audio, but since there are plenty of people
    > here who know about electricity...
    >
    > Twice this summer, I've lost equipment during a thunderstorm. Last
    > week, I got a surge bad enough to not only fry my garage door opener but
    > shatter the bulb! I have whole-house protectors at the service entrance
    > (Cutler-Hammer CHSP 3-way), and some equipment is on power-strip surge
    > protectors as well. All of these protectors still have their
    > "protected" light lit. A few breakers did trip, which is odd - as I
    > understand it, most surges are too short to trip a breaker.
    >
    > The power company wasn't aware of any strikes in my area. Is it
    > possible for a nearby ground strike to somehow induce a surge in my
    > power lines, bypassing the surge protectors?
    >
    > --
    > Jay Levitt |
    > Wellesley, MA | Hi!
    > Faster: jay at jay dot eff-em | Where are we going?
    > http://www.jay.fm | Why am I in this handbasket?


    Any lightning protection system is only as good as the electrical
    grounding
    system it is connected too. Hire someone competent to come in and evaluate

    your grounding system. That is the foundation piece, and a so so protection

    system with an excellent ground is better than the best whiz-bang device
    with
    a crappy ground.
    WIth the weather system crapping on the northeast right now, lighting
    risk
    is rather high for the next week or so. One thing you can do is check and
    tighten all the ground wire connections from your power panel to the ground
    system. ( Which is probably your water pipe. )

    --Dale
  7. On Tue, 5 Aug 2003 15:07:55 -0400, Jay Levitt <jay+news@jay.fm> wrote:

    >The power company wasn't aware of any strikes in my area.


    Why would they?

    > Is it
    >possible for a nearby ground strike to somehow induce a surge in my
    >power lines, bypassing the surge protectors?


    Yes. The EMP from a million amperes current is often more of a
    threat than the direct conduction. Good lightning protection for
    modern electronics must include awareness of wiring, signal
    and power, as antennas.

    Fortunately, any effort expended here also helps to minimize
    RFI, power switching and light dimmer, etc. noise problems.
    Win-win.


    Chris Hornbeck,
    guyville{at}aristotle{dot}net
  8. Dale Farmer wrote:
    >
    >
    > Any lightning protection system is only as good as the electrical
    > grounding system it is connected too. Hire someone competent to come
    > in and evaluate your grounding system. That is the foundation piece,
    > and a so so protection system with an excellent ground is better than
    > the best whiz-bang device with a crappy ground.


    Yes, yes, yes, yes. I can't stress this enough.



    > One thing you can do is check and
    > tighten all the ground wire connections from your power panel to the ground
    > system. ( Which is probably your water pipe. )


    Unlikely a recent inspection would tolerate water pipe grounding (at
    least in any of the jurisdictions I've worked under.)
  9. Jay Levitt wrote:

    > In article <1060118808.696787@nnrp2.phx1.gblx.net>, kurt@nv.net says...
    >
    >> Under $50 for an LA302 http://www.deltala.com/ will dissipate most of
    >> the problems.

    >
    >
    > Is this actually an improvement over a whole-house surge suppressors?
    > Cutler-Hammer sells both suppressors and arrestors; they call their
    > suppressors "best" protection, while they call their arrestors "good".
    > I'm a software guy, so any explanation or pointers would be helpful... I
    > can find surprisingly little info via Google.


    If the Cutler-Hammer device uses MOVs it won't provide the same level of
    lightning protection as the SOVs used in the Delta product. MOVs are
    designed for a different surge profile and also degrade over time from
    small surges.

    http://www.deltala.com/whydelta.htm and http://www.deltala.com/how.htm
    explain some of this.
  10. Dale Farmer

    Dale Farmer Guest

    Kurt Albershardt wrote:

    > Dale Farmer wrote:
    > >
    > >
    > > Any lightning protection system is only as good as the electrical
    > > grounding system it is connected too. Hire someone competent to come
    > > in and evaluate your grounding system. That is the foundation piece,
    > > and a so so protection system with an excellent ground is better than
    > > the best whiz-bang device with a crappy ground.

    >
    > Yes, yes, yes, yes. I can't stress this enough.
    >
    > > One thing you can do is check and
    > > tighten all the ground wire connections from your power panel to the ground
    > > system. ( Which is probably your water pipe. )

    >
    > Unlikely a recent inspection would tolerate water pipe grounding (at
    > least in any of the jurisdictions I've worked under.)


    Most recent NEC I have handy is the 1993 edition, and water pipe
    grounding at the building entrance was allowable then. I suppose I ought
    to bite the bullet and buy a current edition one of these days.
    ANother important thing to remember is that the electrical code
    requirements are the minimums, not best practice. If an electrician brags
    that all his/her work meets the electrical code, then what they are really
    saying is that their work is just adequate for not setting the building
    on fire. This is also true of most all of the other building codes, they
    are minimum safe levels.
    For a recording studio you want to exceed the building code
    minimums by such a large margin that the inspector can just glance
    at the installation and have no doubt that it safely exceeds the standards.
    As for it being updated to current code in 2001, it depends on just
    which edition of the code, and are their any local variances in your
    town. A ground that meets current electrical code is probably not
    sufficient to ground out the lightning surges that your protector dumps
    onto it, fast enough to protect all your gear.
    Tell the installer that you want a ground system that is sufficient for
    a lightning rod installation. ( typically they dig a trench around the
    building, driving in ground stakes every ten feet or so, and the ground
    stakes are welded to a heavy gauge braided cable, which is also
    buried in the trench. This is also attached to building steel, the re-bar
    in the cement of the building and foundation, and the building power
    ground terminal, making up the grounding system. Never done a
    lightning rod install myself, so don't quote me on that.

    --Dale
  11. Scott Dorsey

    Scott Dorsey Guest

    Kurt Albershardt <kurt@nv.net> wrote:
    >Dale Farmer wrote:
    >
    >> One thing you can do is check and
    >> tighten all the ground wire connections from your power panel to the ground
    >> system. ( Which is probably your water pipe. )

    >
    >Unlikely a recent inspection would tolerate water pipe grounding (at
    >least in any of the jurisdictions I've worked under.)


    The NEC hasn't allowed water pipe grounding since the sixties. BUT, it
    does require that the water system be bonded to the house ground at
    one point. If this goes wrong, you can get all kinds of weird problems.

    But yes, making sure grounds is good is never a bad idea. And if the
    existing ground system is insufficient (and you can talk first to the
    local inspector and explain what has been happening to him, and secondly
    to an outfit the specializes in lightning protection), it's not that
    difficult to add onto an existing ground rod to make a cleaner and lower
    impedance ground.

    Ground impedance at very high frequencies is a big issue, which is why
    the ground wire has to go from the panel straight to the rod without
    any loops or kinks along the way. Lightning is a very fast risetime
    pulse, so you need to think about stuff in the MHz region and not just
    DC.
    --scott
    --
    "C'est un Nagra. C'est suisse, et tres, tres precis."
  12. w_tom

    w_tom Guest

    Code describes earthing for human safety. Same ground may
    be woefully insufficient for earthing surges.

    First, follow the connection from each AC mains wire,
    through Cutler Hammer, to earth ground. How long is that
    distance? If sharp bends, splices, through metallic conduit,
    or bundled with other wires, then positive effects of the
    Cutler Hammer will be negated. Yes, that earth ground wire
    must be separated from all other wires.

    Earthing is 'the' most critical aspect in surge protection
    as so many others have already posted. Earthing by a good
    electrician may be sufficient for human safety but not
    sufficient for surge protection. Surge protectors are simple
    science. Nothing advanced or magical about them. Earthing
    determines surge protection. Details are provided in two
    previous discussions in the newsgroup misc.rural:
    Storm and Lightning damage in the country 28 Jul 2002
    Lightning Nightmares!! 10 Aug 2002
    http://tinyurl.com/ghgv or http://tinyurl.com/ghgm

    Code does not require earthing to be enhanced for surge
    protection. Earthing system must exceed code requirements.
    Even conductivity of earth can be poor - insufficient for
    surge protection - but more than sufficient for code. For
    example, if earthing in sand, then the 'code required' earth
    ground will be woefully insufficient. A surge protector is
    only as effective as its earth ground.


    Jay Levitt wrote:
    > In article <bgovp6$nqs$1@panix2.panix.com>, kludge@panix.com says...
    > > Is your service entrance ground good?

    > It *should* be, in that the whole house was rewired in 2001 to then-
    > current Massachusetts code, and the electrical inspector for Wellesley
    > is a bit of a stickler, and made us go farther than code in a few
    > places. How can I check?
  13. Re: Lightning surges

    There are arc triggered breakers that see a "serious" drain on a system,
    like a unit frying, and do their job of breaking. Simple replacements for
    the panel, and although I think it would work for outside events, it's
    principally designed to stop arc from dangerous internal circuits. I don't
    know what it would do if it saw too much current coming in.

    Plus, were you home when this happened? Do you know how close the strike
    was? Even some of our household equipment and computers and such are
    effected by strikes that can set off a local micro "EMP" burst from 70
    million volts coming close. This would certainly bypass any electronics
    used to monitor/condition/interrupt the power as it's a physical phenomena
    not reduced to using wires.

    Other than that, I did have a field problem in that our actual electrical
    grid was somehow reduced to not being able to handle even the lightest
    electrical storm, of which I complained to my friend/PEPCO employee who
    happened to be the guy that redesigned the grid, so he spent maybe a week
    here about (stopping over for lunch and that damned RUSH everyday) and
    redesigned the grid and it's been pretty darned good for the past maybe 7
    years. So I'd suggest that you find someone at the power company who will
    come over and take a look at what you're running, give him any documentation
    of what's been happening, and I'll bet somebody will get the grid right. I
    mean, hell, most of these engineers aren't doing anything anyway because the
    infrastructure is already built. Doesn't hurt, however, to have a friend
    that just happens to do that for a living.

    --


    Roger W. Norman
    SirMusic Studio
    Roger@SirMusicStudio.com
    301-585-4681




    "Jay Levitt" <jay+news@jay.fm> wrote in message
    news:MPG.1999ca81cacb6b859899ea@news-east.giganews.com...
    > This is nothing to do with audio, but since there are plenty of people
    > here who know about electricity...
    >
    > Twice this summer, I've lost equipment during a thunderstorm. Last
    > week, I got a surge bad enough to not only fry my garage door opener but
    > shatter the bulb! I have whole-house protectors at the service entrance
    > (Cutler-Hammer CHSP 3-way), and some equipment is on power-strip surge
    > protectors as well. All of these protectors still have their
    > "protected" light lit. A few breakers did trip, which is odd - as I
    > understand it, most surges are too short to trip a breaker.
    >
    > The power company wasn't aware of any strikes in my area. Is it
    > possible for a nearby ground strike to somehow induce a surge in my
    > power lines, bypassing the surge protectors?
    >
    > --
    > Jay Levitt |
    > Wellesley, MA | Hi!
    > Faster: jay at jay dot eff-em | Where are we going?
    > http://www.jay.fm | Why am I in this handbasket?
  14. Scott Dorsey

    Scott Dorsey Guest

    Re: Lightning surges

    Roger W. Norman <rnorman@starpower.net> wrote:
    >There are arc triggered breakers that see a "serious" drain on a system,
    >like a unit frying, and do their job of breaking. Simple replacements for
    >the panel, and although I think it would work for outside events, it's
    >principally designed to stop arc from dangerous internal circuits. I don't
    >know what it would do if it saw too much current coming in.


    I think those arc-triggered breakers look for high frequency trash from an
    arc and cut the circuit off when it sees that. Touch lamps will also make
    them shut off, I do know. I'm not sure I like the idea, and I don't think
    they will act fast enough to do any real good in this case.
    --scott

    --
    "C'est un Nagra. C'est suisse, et tres, tres precis."
  15. Nothing will kill 70 million volts hitting any type of wire coming into your
    house, but it's most likely near strikes that are your problem. If 70
    million volts hit a typical grid's wires, it would be clamped down on pretty
    quickly and then you'd get your grid back within seconds. If you get hit
    with about three quick blackouts, then you're done, but still, it's the grid
    doing the clamping, not anything within your house. You can't suppress that
    many volts on a direct hit to any line within a couple of blocks from you.
    These suppressors/arrestors are depending on the grid itself clamping down,
    picking back up after some transformer took the majority of the hit (really
    amazing blue light - like a small nuke).

    What type of location do you live at? I'm about as high here (sea level
    wise, you smart asses) as any house around for about 2 miles, that being I'm
    well over most everything else around my area and nothing higher for a
    couple of miles around. Shit comes close here, thus my two extra grounding
    rods, one for my woodshop and one for the pool equipment, both number 6 8'
    rods buried all the way into the earth. If you're getting hits close enough
    to do that type of damage you might be better off running well grounded
    lightning rods on your roof.

    --


    Roger W. Norman
    SirMusic Studio
    Roger@SirMusicStudio.com
    301-585-4681




    "Jay Levitt" <jay+news@jay.fm> wrote in message
    news:MPG.1999f27c1e9b95cd9899eb@news-east.giganews.com...
    > In article <1060118808.696787@nnrp2.phx1.gblx.net>, kurt@nv.net says...
    > > Under $50 for an LA302 http://www.deltala.com/ will dissipate most of
    > > the problems.

    >
    > Is this actually an improvement over a whole-house surge suppressors?
    > Cutler-Hammer sells both suppressors and arrestors; they call their
    > suppressors "best" protection, while they call their arrestors "good".
    > I'm a software guy, so any explanation or pointers would be helpful... I
    > can find surprisingly little info via Google.
    >
    > --
    > Jay Levitt |
    > Wellesley, MA | Hi!
    > Faster: jay at jay dot eff-em | Where are we going?
    > http://www.jay.fm | Why am I in this handbasket?
  16. Shit, in my original grounding system I had an old fused 60 amp box that got
    upgraded to a 200 amp breaker box, but the idiots that set it up, although
    running a #10 grounding rod (hardly big enough nor long enough), also left
    the box tied to the water pipe feeding the house, of which it was gavalnized
    steel. In order to get the correct ground setup I had to decide to cut the
    ground on the waterpipe and go with the grounding rod. I've since pulled
    that one and put in three #6 8' grounding rods, basically establishing three
    separate electrical services throughout the property (household ground does
    not go to the woodshop nor the pool).

    There are some things you can do within the confines of your own property to
    get better power. If the power company won't offer you better power, then
    you may be stuck with doing some of this yourself. You can get air powered
    palm nailers that will take a #6 8' copper rod and put it 7' 11" into the
    ground in about 15 seconds. I think that's the thing that scares most
    people from doing their own grounding work. Trying to drive the rod in.
    Short work with the right tools.

    --


    Roger W. Norman
    SirMusic Studio
    Roger@SirMusicStudio.com
    301-585-4681




    "Kurt Albershardt" <kurt@nv.net> wrote in message
    news:1060128750.843378@nnrp2.phx1.gblx.net...
    > Dale Farmer wrote:
    > >
    > >
    > > Any lightning protection system is only as good as the electrical
    > > grounding system it is connected too. Hire someone competent to come
    > > in and evaluate your grounding system. That is the foundation piece,
    > > and a so so protection system with an excellent ground is better than
    > > the best whiz-bang device with a crappy ground.

    >
    > Yes, yes, yes, yes. I can't stress this enough.
    >
    >
    >
    > > One thing you can do is check and
    > > tighten all the ground wire connections from your power panel to the

    ground
    > > system. ( Which is probably your water pipe. )

    >
    > Unlikely a recent inspection would tolerate water pipe grounding (at
    > least in any of the jurisdictions I've worked under.)
    >
    >
    >
    >
  17. Shit, I'm answering every post. As far as electricians who brag they
    absolutely have to meet code to accept a job that might be under the
    inspector's wire, I had an electrician in last year who took my design for
    the sub-panel and circuits outside for the woodshop and pool, and basically
    gave me his stamp of approval as long as I dug a 12" trench a shovel wide
    for the entire 125' of 60 Amp 6/2 cable necessary to do the job. This was
    last year and I hurt my back, so I hired his "laborers" to do the job. I've
    had to re-dig up that job because the last two thirds, done by the
    electrician's helpers, was only 4 to 6" deep and he mounted electrical that
    shouldn't, by code, be closer than 5' to the pool DIRECTLY ONTO THE POOL.

    Now I'm a kinda hands on guy, so when I saw this I called my Pepco friend
    back over, and I've since redone the electrical to meet code even if an
    inspector isn't coming over. But in some cases, maybe an inspector is the
    best way to get the local utility to do it's job. If not, prepare to learn
    something about electricity and then make some design changes. The concept
    of a field wide grounding system isn't that big of a deal. It takes less
    time than the damage that can ensue costs.

    --


    Roger W. Norman
    SirMusic Studio
    Roger@SirMusicStudio.com
    301-585-4681




    "Dale Farmer" <Dale@cybercom.net> wrote in message
    news:3F305B16.161DD31B@cybercom.net...
    >
    >
    > Kurt Albershardt wrote:
    >
    > > Dale Farmer wrote:
    > > >
    > > >
    > > > Any lightning protection system is only as good as the electrical
    > > > grounding system it is connected too. Hire someone competent to come
    > > > in and evaluate your grounding system. That is the foundation piece,
    > > > and a so so protection system with an excellent ground is better than
    > > > the best whiz-bang device with a crappy ground.

    > >
    > > Yes, yes, yes, yes. I can't stress this enough.
    > >
    > > > One thing you can do is check and
    > > > tighten all the ground wire connections from your power panel to the

    ground
    > > > system. ( Which is probably your water pipe. )

    > >
    > > Unlikely a recent inspection would tolerate water pipe grounding (at
    > > least in any of the jurisdictions I've worked under.)

    >
    > Most recent NEC I have handy is the 1993 edition, and water pipe
    > grounding at the building entrance was allowable then. I suppose I ought
    > to bite the bullet and buy a current edition one of these days.
    > ANother important thing to remember is that the electrical code
    > requirements are the minimums, not best practice. If an electrician brags
    > that all his/her work meets the electrical code, then what they are really
    > saying is that their work is just adequate for not setting the building
    > on fire. This is also true of most all of the other building codes, they
    > are minimum safe levels.
    > For a recording studio you want to exceed the building code
    > minimums by such a large margin that the inspector can just glance
    > at the installation and have no doubt that it safely exceeds the

    standards.
    > As for it being updated to current code in 2001, it depends on just
    > which edition of the code, and are their any local variances in your
    > town. A ground that meets current electrical code is probably not
    > sufficient to ground out the lightning surges that your protector dumps
    > onto it, fast enough to protect all your gear.
    > Tell the installer that you want a ground system that is sufficient

    for
    > a lightning rod installation. ( typically they dig a trench around the
    > building, driving in ground stakes every ten feet or so, and the ground
    > stakes are welded to a heavy gauge braided cable, which is also
    > buried in the trench. This is also attached to building steel, the re-bar
    > in the cement of the building and foundation, and the building power
    > ground terminal, making up the grounding system. Never done a
    > lightning rod install myself, so don't quote me on that.
    >
    > --Dale
    >
    >
  18. Re: Lightning surges

    Neither did I know how they'd respond. Seems good protection should be
    available from the gozintas and gozoutas. Once something serious gets into
    the gozintas, it's too late to protect the gozoutas. Like Herman's Hermits
    said, This Door Swings Both Ways.

    --


    Roger W. Norman
    SirMusic Studio
    Roger@SirMusicStudio.com
    301-585-4681




    "Scott Dorsey" <kludge@panix.com> wrote in message
    news:bgr1uu$8mm$1@panix2.panix.com...
    > Roger W. Norman <rnorman@starpower.net> wrote:
    > >There are arc triggered breakers that see a "serious" drain on a system,
    > >like a unit frying, and do their job of breaking. Simple replacements

    for
    > >the panel, and although I think it would work for outside events, it's
    > >principally designed to stop arc from dangerous internal circuits. I

    don't
    > >know what it would do if it saw too much current coming in.

    >
    > I think those arc-triggered breakers look for high frequency trash from an
    > arc and cut the circuit off when it sees that. Touch lamps will also make
    > them shut off, I do know. I'm not sure I like the idea, and I don't think
    > they will act fast enough to do any real good in this case.
    > --scott
    >
    > --
    > "C'est un Nagra. C'est suisse, et tres, tres precis."
  19. Scott Dorsey

    Scott Dorsey Guest

    Roger W. Norman <rnorman@starpower.net> wrote:
    >
    >Now I'm a kinda hands on guy, so when I saw this I called my Pepco friend
    >back over, and I've since redone the electrical to meet code even if an
    >inspector isn't coming over. But in some cases, maybe an inspector is the
    >best way to get the local utility to do it's job. If not, prepare to learn
    >something about electricity and then make some design changes. The concept
    >of a field wide grounding system isn't that big of a deal. It takes less
    >time than the damage that can ensue costs.


    A lot of electricians just plain don't know the code outside the little
    area where they normally work. The code is big and it's pretty dense,
    and it can be difficult to read because it explains what to do but never
    why it's necessary.

    If he's never looked at the swimming pool section of the code, he might
    very well not know that this is a bad thing to do.

    I know that I have had a lot of nightmares dealing with licensed electricians
    at festival gigs and film shoots who have never used remote generators and
    don't know about the varied and unusual grounding regulations for remote power
    systems. (Regulations that do make sense if you sit down and really think
    about them, but which can seem alarming if you don't. I had a lot of fun
    explaining to one fellow at the Potomac festival last year that his generator
    had to run ungrounded and that tying it to a ground rod was a code violation,
    but that if it was connected to a fixed trailer it would have to be grounded).
    --scott

    --
    "C'est un Nagra. C'est suisse, et tres, tres precis."
  20. Dale Farmer

    Dale Farmer Guest

    Re: Lightning surges

    "Roger W. Norman" wrote:

    > There are arc triggered breakers that see a "serious" drain on a system,
    > like a unit frying, and do their job of breaking. Simple replacements for
    > the panel, and although I think it would work for outside events, it's
    > principally designed to stop arc from dangerous internal circuits. I don't
    > know what it would do if it saw too much current coming in.
    >
    > Plus, were you home when this happened? Do you know how close the strike
    > was? Even some of our household equipment and computers and such are
    > effected by strikes that can set off a local micro "EMP" burst from 70
    > million volts coming close. This would certainly bypass any electronics
    > used to monitor/condition/interrupt the power as it's a physical phenomena
    > not reduced to using wires.
    >
    > Other than that, I did have a field problem in that our actual electrical
    > grid was somehow reduced to not being able to handle even the lightest
    > electrical storm, of which I complained to my friend/PEPCO employee who
    > happened to be the guy that redesigned the grid, so he spent maybe a week
    > here about (stopping over for lunch and that damned RUSH everyday) and
    > redesigned the grid and it's been pretty darned good for the past maybe 7
    > years. So I'd suggest that you find someone at the power company who will
    > come over and take a look at what you're running, give him any documentation
    > of what's been happening, and I'll bet somebody will get the grid right. I
    > mean, hell, most of these engineers aren't doing anything anyway because the
    > infrastructure is already built. Doesn't hurt, however, to have a friend
    > that just happens to do that for a living.
    >


    Also understand that if the lightning bolt actually strikes your house, or
    along
    your particular street, then no matter what you install, all the electronics in
    the
    house are going to be fried. There is an unbelievably huge amount of energy
    in a lightning bolt. When I was in the fire department, we always listened and
    started getting ready when the dispatcher called out that there was a
    thunderstorm was moving through the area.
    When the lightning actually hit in a residential neighborhood, we could
    count
    on one to three attic fires along the street, usually right next door to each
    other.
    The lightning bolt would strike the neutral/ground conductor on the street
    poles,
    ( this is one of the reasons that the nuetral/ground conductor on the street
    poles
    is the highest one on the pole. ) The current would race along the wire looking

    for grounds to earth. This includes the ground rod in each home power panel.
    But when the surge from the lightning bolt reaches the drip loop at the house,
    the curves and loops would 'confuse' it. ( hand waving a lot of science I never

    really understood anyway. ) and it would keep going in a straight line and blast

    into the side of the house, where the anchor bolt was attached to the structure
    of the house.
    This would blow a hole in the side of the house where the anchor bolt
    was, and ignite anything flammable in the vicinity. Since most folks have all
    kinds of random, mostly flammable, junk in their attic, it would be burning
    nicely by the time we arrived. Nothing beats the fun of climbing up onto
    the roof of a burning house with a saw in the rain and cutting a vent hole
    there, without falling off the roof, or through the roof into the fire.

    What these protection devices do is protect your stuff from the lightning
    strike that hits a little bit further away. You are at the mercy of the power
    companies routing scheme there. And they are not going to change it for
    your convenience. To really protect yourself the best, go to a building that
    is in close enough to the city where all the utilities are buried.

    --Dale

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