Lightning Nightmares!!
Gary W. Sandvik
I've been working in the Electronics/Instrumentation since the
sixties. I really had some bad experiences in the past with damage to
equipment in the laboratory. I thought I had seen some pretty bad
situations.
Until my recent strike at our country setting. As I stated before in
another thread our service feed is underground from the distribution.
We are basically at the end of the distribution. The grid comes down
the road through a small forest area. The past two years, I've
noticed a lot of ground strikes. Along with strikes to the guard on
the high tension system about 1/4 mile away. Closest ground strike
that I witnessed was on a small hill about 1/4 mile away.
Now my nightmare began on 07-28-02 afternoon thunderstorm. We thought
it was over. Grandma and the grandkids were off to get some new
cowboy boots. I settled down to check the local weather. I turned on
the big screen HDTV to the weather channel. They had just started the
midwest forecast when I heard a large boom behind me. Another in
front of me about a 1/2 second later behind the TV. The ceiling fan
was running and I swear it sped up with a humming sound. Alarms
sounded all over the place. Surge protectors, in the den along with
UPSs' in the electronics shop downstairs.
I reset all that would. Most still should that system had faulted. The
UPSs' would not reset. One unit turns out had a fried battery.
Breakers did open in the house panel and the barn panel. The breaker
for the hot water unit tripped. The barn breaker for the fencer
opened. We lost the fencer and a phoneset in the barn.
To make a long story shorter. We have lost over $5000 in equipment. A
lot of lost time. No Big screen TV. The wife is tired of the 19 inch
that we are using until next week. It looks funny having the 19"
setting in front of that 53" HDTV. We are going to get that HDTV
back! Thank God for insurance. Our claim representative is very
understanding.
As for repair of our current HDTV. We had Sears repair come out to get
a repair estimate. Boy, talk about a racket. The modules that need
replaced exceed the cost of the replacement TV. Heck to diagnose the
unit we would have to spend about $1000. Then they could check the
other sub-assemblies since the HV module sources other assemblies.
The next timing assembly cost over $1000 plus the $156 labor charge.
That's over $2000 to see if the TV can be fixed. We only paid $3200.
Of course the insurance company said 'get another unit'. We priced the
same unit at Sears for $2400 out the door to our house. What a
difference a year makes.
The other equipment replacement costs are over $2300. I'm lucky to
have alot of spares so that I could get something back on-line. It
has been over 2 weeks and we will probably get this settled on
Monday. I will of course have to do all the leg work to get
everything, HDTV, computer components and other equipment.
Plus is that I'm getting to know my utility people. The services are
there so why not use them. They are willing to check their systems.
No questions asked. Heck our power utility was out within an hour
after reporting the strike. A lot of local damage. Most of it was
with another utility. We are at the division of the two local power
utilities.
All the claims we have had in the past on our insurance were weather
related. Heck we had a 28' cruiser picked up by a tornado and placed
it on the dock a few years ago. That was not a lite boat. A 1974
Silverton Fly bridge that weighed about 10,000 wet.
Don't mess with Mother nature!
--
Regards and God Speed,
Gary g...@mtco.com
The magic is in the magician not the wand!
w_tom
that End of Line Transformers tend to be a location of high CG
strike activity. Essentially, your own experiences are
consistent. However the incoming direction of a thunderstorm
may also be significant. For example, if a storm approaches
from the same direction as the utility wires, then CG activity
may be less. But if the storm approaches from the opposite
direction, then CG activity - strikes seeking earth ground in
the direction of that utility line - may be more frequent.
I remember references to using White Pine as lightning
protection. According to his observations, a line of white
pine trees between the house and incoming storm would act as
protection - much like air terminals (lightning rods).
Interesting idea. I cannot even speculate as to the validity
of his observations. But it is worth considering.
Gary W. Sandvik
> Mark Jordan in a paper summarizing his observations notes
> that End of Line Transformers tend to be a location of high CG
> strike activity. Essentially, your own experiences are
> consistent. However the incoming direction of a thunderstorm
> may also be significant. For example, if a storm approaches
> from the same direction as the utility wires, then CG activity
> may be less. But if the storm approaches from the opposite
> direction, then CG activity - strikes seeking earth ground in
> the direction of that utility line - may be more frequent.
>
> I remember references to using White Pine as lightning
> protection. According to his observations, a line of white
> pine trees between the house and incoming storm would act as
> protection - much like air terminals (lightning rods).
> Interesting idea. I cannot even speculate as to the validity
> of his observations. But it is worth considering.
>
>
Hi,
w_tom, I tend to agree but why the lightning hit the lines instead of
of a nearby tree? Only God knows! In my checking of the immediate area
the storm seemed out of the southwest, the distribution being east to
west. The high tension system runs from southwest to the northeast.
Activity for this systems seems high. Our grid stops at the end of
the lane then under ground to the transformer. The neighbors pole
with the pig is at a right angle to the distribution line. I still
think his pig was hit and then the reflection was to our transformer.
I would like too source the white paper. I will search on 'Mark
Jordan' and strike activity. Any other data on the presenter?
Louis Boyd
the probablilty of fires and electrocution, and it works. They aren't
really designed to prevent damage to electronic equipment.
For 20 years I designed microwave systems many of which were located on
mountaintops, and for the past 10 years I've operated an astronomical
observatory. Heres what I've learned.
1. Locate electronic equipment in metal skinned buildings without long
air gaps. Painted steel is fine.
2. Minimize the number of wires entering the building and run them
through a single location
3. Protect ALL wires entering the building with MOV's, gas tubes, or
spark gaps as appropriate.
4. Ground the protectors to the building at the point they pass through
the skin of the building.
5. Ground the building itself using a ring ground larger than the base
of the building. This only protects the concrete under the building
from being shattered by a direct stroke. It too is attached only at the
entrance "window".
6. Only ground the equpipment inside the building to a single point on
the building skin. The same point as the protector grounds. Plywood
and tile floors make adequate insulators inside.
7. Don't attach expensive equipment directly to incomming power lines.
Isolation transformers and UPS's provide cheap protection.
8. Use fiber optics or microwave for high speed communications out of
the building.
9. Two tall lightning rods (like flagpoles) on either side of the
building, separated by about 50-75 feet, with radial conductors running
away from the protected building and attached to remote ground rods and
NOT nonnected to the building will take the majority of lightning hits.
The radials should be well away from power or communication lines,
Lightning rods attached to a metal building don't make any significant
difference for the equipment inside, but may protect against burning the
paint or burning small holes in a thin steel roof.
Lightning rods on a wooden structure won't protect electronic equipment
inside but they will reduce the chance of fire. On concrete block
buildings lightning rods will reduce structural damage. When I say
lightning rods I mean properly installed and grounded ones.
Absolute lightning protection isn't possible, but you can reduce the
frequency and cost of damage caused by lightning with only a moderate
effort and expense. It's easier to
to put in proper protection when the building is constructed. I've had
no lighting damage other than replacing protectors at my observatory
which contains 25 computers and two microwave systems in ten years.
We receive a couple of direct lightning hits per year. I have heavy
MOV's followed by an isolation transformer on the power entrance and a
phone line with two sets of gas tubes and a longitudinal choke. All
other communcations is fiber optic. We did have one fire started by
lightning hitting a tree below the observatory but put it out before it
did damage.
--
Lou Boyd
http://www.fairobs.org
Norm wrote:
>
> X-No-Archive: Yes
>
> As one lurker who lives on a Poconos ridgeline with worse lightning
> storms than in Tampa, I'm very interested in more data or pointers.
> I've priced lightning rods, $2500, but that was years ago and didn't
> account for an added 1000' of elevated deck.
> Norm (blessed with a lot of tall pines)
> Any sufficiently advanced technology is indistinguishable from
> masochism <me>
ConnieG999
writes:
>As one lurker who lives on a Poconos ridgeline with worse lightning
>storms than in Tampa,
Oh, I dunno...depends on how you define "worse lightning storms."
The corridor from Tampa Bay, FL to Titusville, FL (a.k.a. "Lightning Alley")
receives the most lightning in the United States on an annual basis. Lightning
is the #1 weather killer in Florida, more than all other weather deaths
combined. This area of Florida has, on average, more than 100 days with
thunderstorms per year.
Now... Pennsylvania DOES lead the states in lighting damage....But what's the
criteria that makes Pennsylvania storms "worse?" (G)
Connie
w_tom
Virginia. Florida has many thunderstorms. But the frequency
of CG type strikes is what determines who really has a
lightning surge protection problem. My personal observations
are that the probability of CG strikes varies significantly
just within adjacent towns. Data from the NLDN will
demonstrate same.
BTW, FL is not the lightning capitol of the world. FL is
actually far down the list at number 5 or 8.
Major factor in lightning damage involves geology - types of
soil - is the earth monolithic, etc. Then again, so many PA
homes are older types with all but no earth ground - or in
some cases, literally no earth ground. Just another possible
reason why.
The author did not claim PA as being worse. He stated his
unique neighborhood has severe CG lightning problems.
Severity must be analyzed in little areas because frequency of
CG strikes varies that much locally.
w_tom
w_tom
building UPS. Plug-in UPSes connect electronic equipment
directly to AC mains when not in battery backup mode.
Furthermore, they have no effective connection to earth
ground. Building wide UPS systems have the short connection
to central earth ground and often don't provide power via a
direct connection to AC mains.
The entire surge protector circuit in a plug-in UPS is
equivalent to that in a power strip surge protector. So
equivalent that they are both rated in joules. A plug-in UPS
is no better surge protector than a power strip surge
protector.
Big difference between building UPS systems and that little
plug-in UPS - that is really nothing more than a switched
battery backup box. Plug-in UPSes are only for protection of
data - not effective surge protection for hardware.
Louis Boyd demonstrates what surge protection is about.
Another summarizes the same concepts:
http://scott-inc.com/html/ufer.htm
ConnieG999
> BTW, FL is not the lightning capitol of the world. FL is
>actually far down the list at number 5 or 8.
>
Right. I said Florida is the lightning capital of the United States, which it
is. I think maybe somewhere in central Africa is #1?
-------------------
> The author did not claim PA as being worse.
No, not specifically...he mentioned Poconos. I was assuming, which is, of
course, a mistake.
------------------
>>But the frequency
>>of CG type strikes is what determines who really has a
>>lightning surge protection problem.
Now that's exactly what the "precise" answer would be, and does answer the
question concerning "worse." I was, however, being kinda facetious with my
post. You come live down here in Lightning Land and see how the "problem"
becomes very large very fast! (G)
----------------
>> The highest percentage of Cloud to Ground strikes is in West
>>Virginia.
Now THAT's interesting. But of course, with the terrain, most strikes probably
don't affect either people or property.
I never would have guessed that one. Would you mind telling me where you got
all your excellent facts? I'd sincerely like to learn more.
--------------
Here's the statistic that *I* was using to define "worse:"
"Not surprisingly, Florida has the highest number of lightning-related deaths
in the United States. From 1959 to 1994, lightning claimed the lives of 345
people in the Sunshine State. Runner-up North Carolina, by contrast, suffered
165 lightning-related mortalities." (www.disasterrelief.org)
Guess I was counting PEOPLE, not PROPERTY. So, we can BOTH be right! LOL!
Connie
John Eaton
: w_tom, I tend to agree but why the lightning hit the lines instead of
: of a nearby tree? Only God knows! In my checking of the immediate area
: the storm seemed out of the southwest, the distribution being east to
: west. The high tension system runs from southwest to the northeast.
: Activity for this systems seems high. Our grid stops at the end of
: the lane then under ground to the transformer. The neighbors pole
: with the pig is at a right angle to the distribution line. I still
: think his pig was hit and then the reflection was to our transformer.
Lighting can strike near a line and still cause a lot of damage on the
line even if there is no direct contact. The EM flux from the strike will
hit the loop formed by your powerlines and ground and a current is induced
in that loop. I believe we can thank Mr Ampere for this law.
Similar to the NEMP where one well placed aerial nuke can knock out the
power grid over half a continent. Solar storms can also cause problems
especially in northern areas. During high solar activity the nations
power grid is actually split into mutiple smaller cells to keep it from
failing.
John Eaton
w_tom
electromagnetic fields onto a transistor never suffer damage
from nearby strikes. Voltages on an open wire created by a
nearby strike is high (on the order of thousands of volts)
until a trivial load is applied. Then that wire voltage drops
drastically. Both demonstrate the problem with damage from
nearby strikes. It just does not transfer sufficient energy
even to damage the transistors in that portable radio - the
device that concentrates EM fields on the transistor.
IEEE papers discuss induced transients as a condition that
occurs when the building (or incoming wires) suffer a direct
strike. Induced surges are adjacent wires - when the primary
wire is carrying the direct strike inside the building. The
destructive induced strike occurs when one wire is carrying
high currents. Induced surges because an open circuit wire
has a high voltage really is not a threat. Those high
voltages from the nearby strike are similar to static electric
shock - high voltages but not enough current to cause any
damage.
Any building properly wired for protection from direct
strikes has more than enough protection also for voltages
created by nearby strike. Most so called nearby strikes may
actually be direct strikes. Just that the owner who suffers
damage does not understand how the surge entered and left the
appliance. Induced surges are a condition created when a
direct strike has entered the building. Nearby lightning
strikes don't transfer sufficient energy to even damage
portable radios. Any surge protection system installed for a
direct strike is grossly more than adequate to protect from
any nearby strike.
Gary W. Sandvik
> It should be noted that plug-in UPSes are different from a
> building UPS. Plug-in UPSes connect electronic equipment
> directly to AC mains when not in battery backup mode.
> Furthermore, they have no effective connection to earth
> ground. Building wide UPS systems have the short connection
> to central earth ground and often don't provide power via a
> direct connection to AC mains.
>
> The entire surge protector circuit in a plug-in UPS is
> equivalent to that in a power strip surge protector. So
> equivalent that they are both rated in joules. A plug-in UPS
> is no better surge protector than a power strip surge
> protector.
>
> Big difference between building UPS systems and that little
> plug-in UPS - that is really nothing more than a switched
> battery backup box. Plug-in UPSes are only for protection of
> data - not effective surge protection for hardware.
>
> Louis Boyd demonstrates what surge protection is about.
> Another summarizes the same concepts:
> http://scott-inc.com/html/ufer.htm
>
Hi,
w_tom, I agree that Louis Boyds' is a good example of lightning and
protection. The ufer paper I've read before an it is a good reference
for someone who is building anew. If I was to build a new home or
structure I would certainly utilize the ufer technique. Parallel
earthing/bonding is an accepted practice as another case to use when
possible.
But since I'm not building again then the multiple ground or earthing
rod would be a good means to insure the proper earthing as long as
the methods used are proper. I still haven't located my current NEC.
But using a older issue the methods presented are possible with my
installation.
The building UPS system vs a plug-in UPS is correct. The primary use
for the plug-in is for data recovery or loss prevention reasons along
with small signal transient filtering. Most 'good' plugin units do
provide a good means of filtering along with fair surge protection.
I've maintained and repaired both type of systems. The building
UPS/large System UPS can be a nightmare to maintain. The battery
banks can really cause problems. Especially if the strapping is not
maintained properly. The earthing was never a big deal with these.
Most of the problems develop around the batteries not the controls.
And the plugin units are really throw away devices. The only real
serviceable device is the battery replacement. But generally it is
cheaper to replace the whole unit.
w_tom
connect central earth ground to a wire loop around the
building. If I remember the NEC requirements - 4 AWG copper
buried at least 18 inches deep and 2 feet from the building
foundation. Once people used to install it by hand. Is
lightning more painful?