Shareware Overload Trio 2/Shareware Overload Trio Volume 2 (Chestnut CD-ROM).ISO/dir40/lightng1.zip/LIGHTING.TXT

Text File | 1993-04-22 | 23KB | 473 lines

            A LAYMAN'S GUIDE TO SURGE "PROTECTORS"
                    by Todd Preston

Ooooh I hate that "P" word.  The use of the word PROTECTORS is
silly, as is the word ARRESTOR. They imply that you can PROTECT
your electronics by ARRESTING the lightning.  (Fat chance static
breath).  We should use the word divert...read on to see what I
mean.

I have seen thousands of dollars spent on sophisticated
electronics diversion devices, only to have massive damage occur
to the supposedly protected equipment.  Why?...because the
installers (or salespeople) lacked a fundamental technical grasp
of what they were trying to accomplish.  You cannot stop a
lightning strike.  Your job is to divert the energy safely away
from your computer equipment.  The purpose of this document is to
give you the knowledge required to do so.  Maybe we can take some
mysteries out of the topic, and debunk some myths as we go.

Reinforcing your computer and its associated hardware against
damaging impulses is an effort well worth undertaking.  While
equipment replacement is inconvenient and costs dollars, lost
data is lost data.  The damaging impulses can come from many
places, but will enter your computer system by one of two ways.

               1. The electrical wall outlet.
               2. The telephone modular jack.

Protect your computer from impulses coming in on the power and
phone lines, and you have effectively built a sandbag dike around
your computer system.  There is no way to reinforce the roof over
your system (diverting a direct lightning strike.  Don't bother
trying.  If lightning blows a hole in your roof, I doubt if
you're going to be too concerned about your computer.

Damaging impulses can be broken down into two categories:

 Spikes

     Spikes are short lived, high level "blips" that ride into
     your computer on top of the 117 volt level of the power
     line, or on top of the signal level on the telephone line
     connected to your modem.  If they are large enough, they
     will usually blow out some components.  Spikes have rise
     times in the nanosecond range, and pulse lengths up to 100
     microseconds.  They are hard to remove, because they happen
     so fast. Spikes are usually attributed to lightning strikes,
     whether local or distant.  Their amplitude ranges from
     hundreds to thousands of volts.  Spikes can cause
     unexplained computer rebooting, system lockup, corrupted
     data, equipment failure, etc.

 Surges
     Surges are longer lived, lower level "waves" that ride atop
     the 110 volt level of the power line.  They have rise times
     in the microsecond range, and pulse lengths of up to a
     second.  Surges are easy to "catch" because they are slower,
     but are hard to remove.  (Since they last longer, they
     contain much more power than spikes).  Surges are usually
     attributed to motors: such as air conditioning and
     refrigeration compressors, drill presses, air compressors,
     pool pumps, etc.  Normally these types of motors pose few
     transient problems to computers.  But when they come on line
     in a locked rotor state (unable to start to move), or when
     they blow up, they draw huge amounts of current.  This
     lowers the line voltage.  When the fault goes away the line
     voltage surges big time.  During an electrical storm, entire
     city blocks of "motors" surge after a temporary blackout.

With todays electronic switching type of power supply, electronic
equipment is less susceptible to surge damage than equipment was
say 10 years ago.  That's all fine and dandy for manufacturers
literature, but I don't want my electronics stuff seeing 375
volts for 250 milliseconds!

The answer is the spike/surge diverter, which clamps the
high-voltage pulse at tolerable levels.  So let's talk about how
we can keep those killer pulses out of your electronics.  There
are products on the market that are sucker buys, and many
products that are not.  You can pay 40$ for a line cord, outlet,
and a 25 cent MOV.  You think you're protected, but woe unto you.

Diverters come in four generic types.  Each type has its
strengths and its weaknesses, which are outlined below.

A.  The special silicon avalanche diode (Transorb) offers:---

 + 1. Ideally fast response time. (in picoseconds)
 + 2. Low level voltage threshold available.
 + 3  Moderate cost.  ( $1.40 ea. @ 100+ quantity)

 - 1. Catastrophic failure at high current loads (above 500 amps)

B.  The Metal Oxide Varistor (MOV) offers:-------------------

 + 1. Very high load current capability. (up to about 5000 amps)
 + 2. Dirt cheap

 - 1. Markedly slower reaction speeds. (in nanoseconds)
 - 2. Effectiveness decays to nearly zero after heavy repetitive
      activity.

C.  The lone gas discharge tube offers:---------------------

 + 1. Extremely high load current capability. (10,000+ amps)

 - 1. Even slower response time. (in microseconds)
 - 2. Crowbar action blows circuit breaker.
 - 3. High cost.


D.  The hybrid designs offer:--------------------------

 + 1. The best of two or three products, by complementing
      characteristics.

 - 1. Highest cost.


I use all three components in my hybrid designs.  Here's why:

     The Transorb is the first to react, clamping the spike at
the peak voltage level.  Before the Transorb blows up from
passing to much current, the MOV "kicks in" and relieves the
Transorb.  If there's enough sustained power in the spike to fire
the gas tube (crowbar) then the MOV gets cut some slack.

The majority of the manufacturers have gone away from using the
gas tube hybrids, and use hybrids that contain Transorbs and
MOV's.  Some have internal auto reset circuit breakers, RF chokes
(10 turns of # 14AWG enameled wire), and other features included
in them.

Cheaper diverters may offer only one MOV, protecting only one of
the three possible power line entry points for a voltage spike
("one-way diversion").  These cheap diverters are out there in
mass.  Buyer beware.  Read the packaging!  If you buy in an
over-the-counter store, ask the salesperson about the device (if
you really are interested in a laugh).  As usual, the people at
Radio Shack are quite helpful, and frequently quite
knowledgeable; so they prove the exception to the rule.  The
'Shack offers quality products but does not currently offer
anything other than good quality 3-way MOV based diverters.

They do offer an excellent line of UPS oriented equipment.

It is a tragedy to pay 20$ and up for something that comes in
decorator colors and contains a single high voltage value MOV.
These "gimmick" products are normally sold in
"department/hardware/lumber" type stores. Once again, beware!

Non-crowbar diverters are rated according to:

response time:  time it takes to suppress the spike in
nanoseconds

clamping level: (the peak voltage ((at a specified amperage))
                remaining after the device has sustained a
                6000-volt spike)

power rating:   (the maximum transient energy which can
                repeatedly be absorbed without failure,
                measured in joules).


Since there are three power "legs" to protect in any circuit,
true diversion boils down to meaning a three-way line network.

  Line (hot)-to-neutral -- (called differential or normal mode)
  Ground-to-line --------- (called common mode)
  Ground-to-neutral ------ (also called common mode)

Most manufacturers describe this as:

     Line to Line -- (differential mode)
     Line to ground -- (common modes)

                       HOT             NEUTRAL
                      LINE 1            LINE 2
      GROUND            │                  │             GROUND
        │               │                  │                │
        │           ╔═══╧══════════════════╧═══╗            │
        ├───────────╢      GAS      TUBE       ╟────────────┤
        │           ╚═══╤══════════════════╤═══╝            │
        │               │                  │                │
        │               │                  │                │
        │   ╔══════╗    │      ╔══════╗    │     ╔══════╗   │
        ├───╢ VR 1 ╟────┼──────╢ VR 2 ╟────┼─────╢ VR 3 ╟───┤
        │   ╚══════╝    │      ╚══════╝    │     ╚══════╝   │
        │               │                  │                │
        │   ╔══════╗    │      ╔══════╗    │     ╔══════╗   │
        ├───╢ MOV 1╟────┼──────╢ MOV 2╟────┼─────╢ MOV 3╟───┤
        │   ╚══════╝    │      ╚══════╝    │     ╚══════╝   │
        │               │                  │                │
        │             ╔═╧═╗              ╔═╧═╗              │
                      ║ L ║              ║ L ║
                      ║ 1 ║              ║ 2 ║
                      ╚═══╝              ╚═══╝


           For ease of illustration, two grounds are shown.

              VR1-VR3 are transorbs. (avalanche diodes)
              L1-L2   are home-made chokes made of 10
                      turns of #12AWG insulated wire


This is the type of device that you would install as your #2
defense.  (At the output of the sub-panel 117v breaker that feeds
your computer)


SSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSS
    WARNING     WARNING      WARNING      WARNING      WARNING

   ALL OF THE TECHNIQUES, PROCEDURES, AND IDEAS CONTAINED   HERE-
   IN DEAL WITH DANGEROUS 117/240 VOLT AC CURRENT. DO NOT ATTEMPT
   ANY INSTALLATION OR MODIFICATION YOURSELF. CONTACT A QUALIFIED
   ELECTRICIAN FOR ASSISTANCE. ALL THE FOLLOWING STATEMENTS APPLY
   TO STANDARD 117/240 VOLT SERVICE ONLY.  FOR ANY 3 PHASE OR 440
   VOLT PLUS CIRCUITS, YOU'RE STUPID IF YOU DO NOT CONTACT A
             LICENSED ELECTRICIAN FOR ASSISTANCE

    WARNING     WARNING      WARNING      WARNING      WARNING
SSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSS



Somebody smack me If I digress a few hundred more times...but
here's an important clarification of terms, their use, and the
criticalness of you understanding them.  We are bridging two
totally different technical fields here, one being Electricity
and the other being Electronics.  Terminology between the two is
just close enough to be dangerous.

MAIN DISTRIBUTION PANEL:  There is a "Main Main" circuit breaker
that is after the meter, which feeds all the breakers in the Main
Distribution Panel.  This Main Breaker will feed such circuit
breakers as:  House Main, Outbuilding Main, Garage Main, Air
Conditioner, Pool Pump, Arc Welder, Outdoor Lites, etc.  You can
think of this Main Breaker as your property's Main Disconnect.
If you kill this breaker your shop loses power, along with your
toaster, your sprinklers, and your porch light.  REMEMBER, THE
HOT SIDE OF A BREAKER IS HOT, WHETHER THE BREAKER IS ON OR
OFF!!!!!!!!...When you trip your "Main Main", the PANEL IS STILL
HOT AND CAN KILL!

SUB PANEL:  Your Property may have several sub panels.  Each sub
panel may or may not have its own "Sub Main" breaker.  You would
have a sub panel in your house, in your garage, etc.  (Every
place you have that is a "separate entity")  The typical sub
panel would normally have its own sub main breaker, feeding
multiple different breakers.

Rephrased, Each meter on your property should feed only one Main
Distribution Panel, which should feed one or more independent Sub
Panels.


A pictorial...............

╔═══════╦ ╔═══════╗   ╔═══════╗ ╔═════════════╗   ╔═══════════╗
║       ║ ║       ║   ║       ║ ║             ║   ║   JONES   ║
║ HIGH  ║ ║       ║   ║ JONES ║ ║   JONES     ║   ║           ║
║VOLTAGE║ ║       ║   ║       ║ ║             ║   ║SUBPANEL"A"║
║       ║ ║ TRANS ║   ║       ║ ║    MAIN     ║   ║           ║
║ POWER ╟─╢ FORMER╟─┬─╢ METER ╟─╢ DISTRIBUTION╟─┬─╢   INSIDE  ║
║ LINE  ║ ║       ║ │ ║       ║ ║    PANEL    ║ │ ║     THE   ║
║       ║ ║       ║ │ ║       ║ ║             ║ │ ║    HOUSE  ║
╚═══════╝ ╚═══════╝ │ ╚═══════╝ ╚═╤════════╤══╝ │ ╚═══════════╝
                    │             │        │    │ ╔═══════════╗
                    │             │        │    │ ║   JONES   ║
                    │          ╔══╧══╗ ╔═══╧══╗ │ ║           ║
                    │          ║JONES║ ║JONES ║ │ ║           ║
                    │          ║POOL ║ ║STREET║ └─╢SUBPANEL"B"║
                    │          ║PUMP ║ ║LIGHT ║   ║           ║
                    │          ╚═════╝ ╚══════╝   ║   INSIDE  ║
                    │                             ║     THE   ║
                    │                             ║   GARAGE  ║
                    │                             ╚═══════════╝
                    │
                    │ ╔═══════╗ ╔══════════════╗  ╔═══════════╗
                    │ ║       ║ ║              ║  ║           ║
                    │ ║ SMITHS║ ║    SMITHS    ║  ║  SMITHS   ║
                    │ ║       ║ ║              ║  ║           ║
                    └─╢       ╟─╢     MAIN     ╟──╢SUBPANEL"A"║
                      ║       ║ ║ DISTRIBUTION ║  ║           ║
                      ║ METER ║ ║              ║  ║  IN THE   ║
                      ║       ║ ║     PANEL    ║  ║   HOUSE   ║
                      ║       ║ ║              ║  ║           ║
                      ╚═══════╝ ╚══════════════╝  ╚═══════════╝

The wire going to the screw of the circuit breaker is the hot
line FOR THE DEVICES FED BY THAT BREAKER.  NOT THE HOT INPUT TO
THE BREAKER.  If your panel is wired properly, this breaker
output wire (device input) will be a black (hot) wire for 117v
breakers, and a black (hot) & a red (hot) OR a black (hot) & a
white (hot) for the ganged or two pole 240v breakers.  (( The
coloration here depends on your local code, the age of the
installation, and whodunit))  There will be two buss strips
located on the side of the panel.  One will be the connect point
for a bunch of white  (neutral)  wires,  and the other will be
the connect point for a bunch of green or bare copper  (ground)
wires.

Depending on the physical characteristics of the gas tubes and
hybrid diverters, and whether the main distribution and subpanel
are surface or flush mounted, you may end up having the
electrician install them 3-4 feet from the panels. They will have
to be connected using code approved methods.  Two lengths of 1/2"
Sealtite<TM> and four Sealtite<TM> connectors will usually be
acceptable, but you must check your local code to be sure.

First, let me describe an ideal diversion system for those of us
on a budget.

     You can easily spend 10,000 dollars or more on grounding
grids, Ufer grounds, dissipative arrays, etc.  Lets save those
for the rich.  We'll do almost as good a job, at low cost.  Keep
in mind that lightning diversion is system oriented.  That is,
one facet of the system can be the best possible, and if any
other portion of the system is deficient or ailing, then the
whole system isn't work a hill of beans.  Even though some of the
diversion components are electrically installed in parallel with
the line, the diversion route is one simple series circuit.
From cloud to a good earth ground.  The old loggers had the "a
chain is only as strong as its weakest link" adage.  I guess
that's why all those sayings were developed. (because they're
true)    Anyway, here we go.


1.   A gas tube device at the building main distribution panel,
     installed after (on the cold sides of) the main circuit
     breaker that feeds the house subpanel. (NOT THE MAIN THAT
     FEEDS THE MAIN PANEL). You want your gas tube on the cold
     side of the House Main. See prior clarification.  I'm
     assuming your computer is in your house.  If you're working
     in your garage, change the words that read "...feeds the
     house", to read "...feeds the garage."

APARTMENT DWELLERS:  This can nearly be an impossibility for
those of you that live in an apartment.  However, I have had good
success with going to the Maintenance Supervisor of the property,
and explaining to him what I wanted to do.  Ask him to show you
the meter room, this is where you will do most of your dirty
work.  There are separate meters for each apartment, and these
separate meters feed a small main distribution panel for your
specific apartment.  This panel will have an apartment main
breaker, along with possibly another for an air conditioning
condensing unit.  You'll add your gas tube device here, after the
apartment main.  It must be installed on the cold side of the
apartment main breaker. (the side feeding your apartment, not the
side coming from the meter).  Worst case, the utility company can
be contacted to rotate (disconnect) your meter while the
electrician installs your device.

HOMEOWNERS:  At least you can do what you wish on your own
property. (sort of).  You still have to follow all the electrical
codes for your State, County, and Municipality.  These codes are
there for your protection, so don't snoot at them.  Locate your
meter, and your main distribution panel should be right
underneath. Hopefully it is surface mounted, and not flush
mounted.  Surface mounts are so much easier to work with, because
you don't have to rip the wall apart to wire in the gas tube
device.  The gas tube is installed on the cold side of the
Breaker that feeds the HOUSE SUBPANEL.  See prior clarification.

2.   A hybrid at the house subpanel, placed on the cold side
     of the circuit breaker controlling the wall outlet you will
     be using.  I'm assuming your computer is located in your
     house.  If you're working in your garage, then change the
     words ..."house subpanel" to ..."garage subpanel".

(If your breakers aren't labeled, here's the opportune time
to do so.)  Plug a portable radio into the desired outlet and
turn it up.  Trip a breaker off (wait 2 seconds) and back on, one
by one, till the sound  goes away.  You'll be dealing with a
breaker that has only one "leg". That is a single 120 Volt
breaker.  Any that are ganged together (trip one, another trips)
or take up two slots in the panel, are 240 Volt breakers.  These
would feed (supply power to) items such as: water heaters,
stoves, dryers...  They better not be feeding your outlets!

3.   An off the shelf 3-way MOV spike diverter screwed captive
     into the DEDICATED duplex receptacle that will be serving
     your computer equipment.  Screwed captive means that the MOV
     diverter is provided with a screw that holds the device to
     the duplex receptacle.  Most require removing the outlet
     cover first.  This last line defense is the package that
     contains two RJ-11 modular phone jacks that will be labeled
     in/out, from phoneline/to modem, or something like that.
     Spike diverters using MOV's should have a colored MOV status
     lamp which goes out if the MOV fails.  In this failed
     condition, the spike diverter will still usually pass
     electrical current through to the equipment, but the current
     will no longer be spike diverted.


  After you have had the electrician install whatever diversion
devices you elect to use, you may think that you are all set.
NOT!  You have diverted the damaging spikes and surges, but to
where?  The lightning was looking for  a way to get to a good
earth ground, that's why it hit in the first place.

  You have to give the spikes and surges a real easy path to
divert to or they will "laugh" at your attempts.  The most
expensive diversion devices are useless unless there is an easy
path for the diverted spikes and surges to dissipate into the
earth.  I can tell you right now, that the schmutzy ground rod
that the power company drove into the dirt 5 years ago near the
base of the meter is not a satisfactory earth ground.  So here's
what to do to make the whole project gel. Don't get disheartened,
it's kinda fun.

  What you are going to do, is drive some ground rods in your
lawn with a sledgehammer, and then connect them all together with
bare copper wire.  Spend an hour or two figuring your materials
list using the included worksheet and flowchart.  Don't hesitate
to barter for some of the items, tools, or labor.  If you know
your materials supplier, try trading them a ground network
installation at their home for your materials and tools.
Substitutions are fine on some items, and are noted where
applicable.

  If your residence has any utilities that enter your home via
underground cables; (phone, cable TV, electric, etc.); you must
locate those cables before you do any digging. As a point of
reference, the utility companies are responsible for maintenance
on the cables up to and including the demarcation device.

  1. Call the appropriate utility company and tell them that you
     are going to be digging in your yard, and you'd like them to
     come out and mark (locate) their lines so you won't damage
     them.  Most utility providers are ecstatic when people ask
     before they dig.  When you call, ask them their name first
     and write it down.  If you get a negative response from the
     1st contact person, go up one supervisory level and try
     again. (get the name before you ask). (If still negative,
     advise them you will hold them personally liable if you are
     injured or damage anything.)  Ask for a date that the
     locator will arrive, and if possible, meet them.

  2. Watch them operate the detector, and don't hesitate to ask
     questions.  They may locate your water input, if it's not
     PVC pipe.  Leave their flags intact while you do your
     rooting around.  I've known the locators to blow it big
     time, and have seen a 2 foot diameter hole augered right
     through a 50 pair phone cable.  The digging contractor was
     not liable in any way, because the utility company had
     "located" (albeit incorrectly) the lines.

On a sheet of paper, sketch the top view of your house, electric
meter, and telephone demarc.  Include major trees, hedges,
swimming pools, driveways, etc.  (as if you were in a hot air
balloon looking down)  You are going to be doing this to scale,
so let 1" equal 2' or whatever.

--------------------------------------
End of Lightnin Divert P1 9/9


I am debugging the flowchart required for the next steps.  They should
be ready in a week (HA).  There will be a parts listing, sources, and
maybe a glossary as well as digging and driving instructions.

  [Lightnin Divert P2 X/Y] ... Coming soon at your local theater.

My Thanx to John Mudge for assisting in the proofreading, and suggestion
offering department.

Todd