Lightning Protection in a Flash

Is it just lightning rods connected to conductor going to ground? In short, yes, but there is a complete science to lightning protection.

Benjamin Franklin invented the lightning rod over 250 years ago and we still use his design today. The biggest difference between his time and now are the electronics and communication equipment we all now have in our homes. This is why surge protection is now important. The difference between structural lightning protection and surge protection follows.

Structural protection is the system briefly mentioned above including lightning rods, conductor, and grounding. Structural protection protects a building from a direct strike which could possibly cause a fire or may super heat steam inside masonry or other structural materials which could then explode.

Surge protection is used to protect the electrical and communication systems and electronic devices in your home, but will not assist in preventing a direct strike. Quality surge protection will not come from a power strip you purchase from a box store. Lightning will not discriminate between an air force base and a residential home. The same quality surge suppression should be installed at both locations. Redundancy is also important in surge protection and it is valuable to protect the main service panel and all sub panels. Every wire entering your home has the potential to carry a power surge, so cable and telephone lines should also be protected.

The lightning rod now has some variations. There are versions of the lightning rod that actively try to attach with lightning. A single active rod can take the place of numerous traditional lightning rods. Another version of the lightning rod dissipates the building ion charge and effectively keeps lightning from locating the structure they protect. This dissipating rod is extremely useful when protecting buildings or tanks containing flammable or explosive materials. It is important to remember that lighting rods need to have two different paths to ground.

The conductor provides an engineered path for lightning to follow to the ground rods. Lightning protection standards only recognize using a braided copper or aluminum conductor with a specified number of strands and a minimum weight per foot. Lightning is a high frequency electrical event and it travels on the skin of a conductor. This is why lightning professionals only use the bare braided wire known as Class 1 or Class 2 lightning conductor to effectively carry the lightning strike down to the ground rods.

Bonding is another component of the protection system. All lightning rods, any conductor used, and the ground rods need to all be electrically continuous. Electrical bonding connections are necessary to those components as well as to any nearby pipe, metal fencing, or other metal bodies. The entire protected site will then have common grounding and its potential will rise and fall evenly with little chance of electrical arcing when lightning strikes.

All this being said, by employing these techniques you can provide a very high level of protection for your property, but still lightning sometimes decides it will not be told what to do!

All About Lightning

As we enter mid-spring and the weather finally begins to warm up a bit, we expect to see quite a few thunderstorms in Oregon. Inspiring awe in some while scaring the pants off others (but not ME, I’m definitely not scared of lightning. No sir,) it is no surprise that cultures all over the world associate lightning with deity. But what exactly is it?

During an electrical storm, the upper portion of the storm clouds has a positive charge and the lower portion has a negative charge. It is not quite clear how the clouds attain these charges in the first place, but one theory is that different forms of liquid (vapor, water and ice droplets) collide as they rise and fall within a cloud. In the collision, electrons are knocked off of the rising moisture and they gather at the bottom of the cloud, creating the negative charge. It is thought that rising moisture then carries a positive charge to the top of the cloud. The charge separation within the cloud is what creates an electric field, the strength of which is related to the amount of charge buildup in the cloud.

When the electric charge inside the cloud becomes very strong, the air becomes ionized (the positive ions and electrons are spaced further apart than before and the electrons can move more freely.) The strong ionization causes the air to begin to break down, allowing for currents to flow in an attempt to neutralize the charge. These currents are called leaders, and they provide a path through the cloud for the lightning to follow. The initial (or stepped) leader does not move smoothly, but jumps in a jagged fashion. Many leaders form at the same time, but the first one to make contact with the ground is the one that gets the lightning.

The entire process is a bit more complicated, but there you have the basics of how lightning is formed. Lightning is much too powerful for even the best of surge protectors to protect against, and it can reach temperatures of 54,000 °F. (For comparison- the surface of the sun is only about 9,900 °F.) An average bolt of lightning carries about 30,000 amps. A single ampere of current is all it takes to kill a human!

Lightning is a complex phenomenon with many variations and exceptions. Sometimes it shows up in the most unexpected of places.

For example, do you know:

Why We See Lightning During Volcanic Eruptions?

If you saw photos of the eruption of Icelandic volcano Eyjafjallajökull that erupted in 2010, you may have seen lightning within the plumes of smoke and thought that they surely must be photoshopped. Not so!

There is still research being conducted into the definitive cause behind lightning within the smoke plumes of volcanoes, but the general consensus involves, of all things, dust. The idea is that dust/smoke/ash particles carry small charges that become amplified during the chaos of rushing out of a volcano. With every collision of one particle with another, the charges become more and more polarized until lightning is inevitable because the polarization becomes too great for the air to resist the flow of electricity. The lightning neutralizes the charge separation, essentially relieving the tension of polarization.

There is another lesser known type of volcanic lightning, however, which occurs right at the mouth of the volcano and is much less orderly (not the ordinary branching, bolting lightning we’re used to seeing), manifesting as chaotic sparks probably as the result of a heavy charge within the volcano itself.

How Many Different Kinds of Lightning There Are?

The answer to this question depends on who you ask, and what you consider a “kind” of lightning. The typical classifications are as follows:

Cloud-to-cloud (intercloud, which is lightning moving between separate clouds, and intracloud, which is lightning moving within the same cloud).

Cloud-to-ground (Less common but more dangerous than cloud to cloud. If anything on the earth is struck by lightning, it was cloud-to-ground.) Cloud-to-ground lightning is more complex than a simple bolt shooting straight from a cloud, however, and includes charges moving up and down from both the cloud and the ground.

Cloud-to-sky (Also known as sprites, cloud-to-sky lightning occurs in the upper atmosphere. They lack the hot temperatures of other types of lightning, and usually have a reddish-orange hue.)

Lightning is also sometimes further specified as:

Ribbon lightning (Successive strokes of lightning are displaced by wind, resulting in a broadened appearance, almost like a double-exposed photo).

Bead lightning (The decay of the luminosity of the bolt of lightning, resulting in a beaded appearance. This happens very quickly and is difficult to capture.)

St. Elmo’s Fire This is not actually lightning, but often closely associated with it and seen during electrical storms. St. Elmo’s Fire (not to be confused with ball lightning as it often is) is the result of a gap in electrical charge. It’s made of plasma (ionized air that emits a glow) and, while lightning is the movement of electricity from a charged point, St. Elmo’s Fire is a coronal discharge that sparks up in the place where there is a drastic difference in charge between the air and an object like the mast of a ship or the steeple of a church. St. Elmo’s Fire is the same thing that happens in a fluorescent tube- essentially a continuous spark, glowing blue because of the particular combination of air molecules. It may also take on a purple hue.

St. Elmo’s Fire is very difficult to find accurate images or videos of. Many videos exist that claim to be St. Elmo’s Fire but are actually just static discharge (a frequent occurrence around airplanes in the midst of storms). An easy way to tell the difference is that St. Elmo’s Fire does not look like lightning- instead it emits a steady glow.

Ball lightning– The most mysterious type of “lightning”, there is some dispute among scientists as to whether ball lightning actually exists. Arc faults along power lines (which appear as large, impossibly bright balls of light) and photographic anomalies are both to blame for the confusion.

How to Stay Safe During a Thunderstorm?

  • Lightning regularly strikes water, so never go swimming or boating during a storm. If you are in the water when a storm begins, get out of the water as fast as you can.
  • Lightning strikes will follow anything that conducts electricity, so stay off your landline phone during a storm and turn off/unplug your computers. If lightning strikes your house, even the most powerful of surge protectors will have a hard time protecting your equipment. (Radio waves do not conduct electricity, so as long as your cell phone is not plugged in to an outlet and you are not standing outside during the storm with the metal device held to your face, it is safe to use it. They do not inexplicably “attract” lightning more than any other object with metal in it).
  • Lightning does in fact strike twice (the Empire State building is struck 20-25 times a year), so don’t rely on old adages for your safety information.
  • If you are caught in a thunderstorm and cannot get inside to safety, crouch low to the ground but do not lay flat. Try to keep as much of your body from touching the ground as possible, because you are in more danger of being injured by currents traveling across the ground after a lightning strike than of being stricken directly by a bolt.
  • A flash-to-bang (seeing lightning to hearing thunder) ratio of 5 seconds equals one mile of distance from the lightning. Ten seconds equals 2 miles, etc.

Lightning in Mythology

One has only to view an electrical storm themselves to understand why so many people have associated lightning and thunder with deity. A few popular myths and legends about lightning:

  • Zeus (Jupiter to the Romans) is the planetary god of thunder, and his primary weapon is the thunderbolt (given to him by the Cyclops).
  • The Thunderbird common to North American indigenous cultures is said to create thunder by the beating of its wings, and lightning is made by glowing snakes that it carries or directly from its eyes.
  • Thor is the Norse hammer-wielding god of thunder.

There is so much more to learn about lightning in all of its various incarnations. It is a stark reminder of the incredible powerful forces of nature that surround us on all sides. Despite how much we learn about it on a scientific level, we may always be inclined to associate this incredible force with deity.

Did You Feel That Lightning Hit You?

Intro:

Did you know you might have been close to being struck by lightning, yet not have felt a thing? If you think that’s impossible, this article will eliminate any doubts you may have. To prove this point, the understanding of how lightning, conductors, and insulators work is important.

Lightning:

To understand how this is possible, you first have to understand lightning. Lightning originates in a thundercloud and is the result of an electrical discharge between the clouds and the grounds of this very Earth. Lightning is produced when ice particles in the clouds collide with each other. The result of the ice particles colliding is the buildup of electrical charges. When the cloud is filled with electrical charges, air currents and moving ice and water particles in the cloud cause positive and negative charges to separate. Positive charges gather at the top of the cloud and negative charges gather near the bottom of the cloud. When there is a substantial negative charge at the bottom of the cloud, a shadow where a positive charge is induced forms on the ground below the cloud, creating a difference in potential. Because opposites attract, when the cloud’s charge becomes sufficient enough, a small path of the negative charge starts making its way towards the ground. At the same time, a path of positive charges moves up from the ground to meet with the negative charges at a certain point. When these paths meet, a bigger pathway is created to let electrons travel towards the ground, which then equals out the difference in potential. Thus, a bolt of lightning leashes towards the Earth at approximately 140,000 miles per hour. The occurrence of a lightning bolt is very short in duration but the electric discharge can contain up to one billion bolts. So how can a person be hit by a lightning bolt and not feel it? It is because the human body is not an effective conductor for lightning.

Conductors and Insulators:

Conductors and insulators are key aspects in understanding why the human body is not an effective conductor for lightning. Conductors are materials that allow for the flow of electrons to travel easily throughout the object. This means that electricity can travel through that particular object. The reason for this is that such objects contain loosely bound exterior atoms that can move freely, allowing the flow of electric current. There exist many examples of good conductors, metals particularly. Many metals, such as iron, aluminum, and copper, are used as electric conductors. This is the reason as to why most wires are made of various metals, preferably copper. Water with “impurities” such as salt and electrolytes can also be considered conductors though not as effective as metals. Insulators, on the other hand, are materials that have high resistance to electric currents. Many nonmetallic objects, such as rubber, wood or glass, are good insulators because the atoms of those items are closely bound, meaning that electric currents cannot move as easily.

So Why Don’t You Feel It?

The difference in potential between the ground and the cloud is very great and a current will be generated between the two. Also, the human body is just naturally a terrible conductor. So, theoretically, when the lightning strikes, the lightning will move around you to hit the ground for two reasons. You are a better insulator than the ground and the difference in potential between you and the cloud is lower than that between the cloud and the ground. So why is it that you don’t feel a lightning bolt hitting you? That is because the current flows around you as opposed to through you.