How to protect your home from lightning

August 30, 2019
By Marcy Shortuse

Lightning is one of the most fickle aspects of nature, as those of us who live in “The Lightning Capital of the World” can attest to. With bolts of energy that can reach temperatures of 50,000 degrees, maintaining a healthy respect for this element is a must.
As scary as that that temperature may sound, lightning is a good thing, too. It helps our planet maintain electrical balance – the Earth is recharged by thunderstorms. The Earth’s surface and the atmosphere conduct electricity easily, the Earth being charged negatively and the atmosphere positively. There is always a steady current of electrons flowing upward from the entire surface of the Earth. Thunderstorms help transfer the negative charges back to Earth (lightning is generally negatively charged). Without thunderstorms and lightning, the Earth-atmosphere electrical balance would disappear in 5 minutes. Lightning also makes ozone-producing chemicals.
Now that we are at the peak of summer heat, lightning has become an almost daily occurrence.
When lightning hits the ground it fuses dirt and clay into silica, the result of which is a rock called a fulgurite, which looks like a misshapen tube.
Everyone knows to go inside when lightning is in the immediate vicinity, but it’s a little-known fact that a bolt from a storm 10 miles away can still strike you. It can also strike a tree you’re standing under, and that can easily hurt or kill you as well. When lightning travels down the tree trunk it turns moisture in the tree into steam, and if it gets under the bark and into the surface moisture of the wood, it rapidly expands. That’s what happens many times when you see a tree “explode.”
While you may not be able to protect your trees from a lightning strike, there is a chance you can protect your home. A lightning protection system will help to reduce hazards if your house happens to be struck directly, by utilizing terminals for lightning discharge.
There are four main dangers to a home being struck by lightning: fires, side flashes, damage to the home’s structure and damage to electronics and applicances in the home.
A fire caused by lightning can start in a home and no one may know it for hours, which is what happened to one of The Gasparilla Inn & Club cottages on the island earlier this month. Even with no apparent point of entry, a bolt of lightning managed to start a fire in the cottage’s attic insulation that wasn’t found until the next day.
Lightning fires can also be caused by blowing out electrical wiring: The heat from a strike can follow the wires inside a wall, and in some cases it will overheat or even vaporize them.
A side flash from a lightning strike can jump from room to room and wall to wall, and it can injure people in the house at the same time. Side flashes can even ignite flammable materials in a garage, leaving everything else intact.
The structure of a home can be damaged by a lightning strike as well. Several months ago, island resident Kim Newlin was surprised (to say the least) when an “out-of-the-blue” strike hit the roof of her home and blew tiles everywhere across the pool area.
If lightning strikes your home and takes the path of your electrical wiring, it can travel through the sockets where your appliances and other electrical devices are plugged in and fry them.
So what can you do to prevent such craziness from happening? You may not want to rely on your “surge protection” zip strips from the hardware store … you may want to dig a little deeper into your pockets and put down the money on a little more elaborate prevention system.
You might have seen small, vertical protrusions on the roofs of some island homes, and not all of them are bird deterrents. Some of them are lightning rods, which come in all shapes and sizes and are connected to conductor cables that carry lightning from the rods to ground rods that are buried deep in the earth. The cables normally run along the tops and edges of a roof and join at a grounding point. The rods, terminals and cables are normally made of copper, but some are made of aluminum.
While some people believe that lightning rods attract lightning, that is not necessarily true. Tall appurtenances such as cell phone towers and church steeples will naturally attract lightning only because they are the tallest structures around.
Another fallacy about lightning rods is that they dissipate the energy from the lightning by draining it, and yet another is that they offer surge protection for the electronics in your home.
Whole-home surge protection devices (SPDs) are a way to combat power surges of all kinds, including those from a lightning strike. They are connected to a home’s electrical service box using metal-oxide varistors (MOVs). Modern homes often come with whole-home surge protectors as an added safety feature.
Your home is a good example of a set of resistors that could be considered to be “connected,” meaning each component of what makes your house a house works in symbiosis with the others. Even though the plumbing and electrical systems in your home aren’t necessarily connected, flash lightning can bridge that gap in a hot minute. In a direct lightning strike, the current will not follow only one path, it will distribute itself across all paths to ground, depending on each path’s resistance.
Unfortunately, not even a full-fledged lightning protection system with rods, cables and grounds will guarantee protection against damage to electronics and computers. For any system to provide 100 percent protection, it must divert all of the lightning current from a direct strike, which is nearly physically impossible. The reason for this is called Ohm’s Law, which states that for a set of resistances connected in parallel, the current will be distributed across ALL resistances, at levels inversely proportional to the different values of resistance.
Installing a lightning tracker app on your smart phone is a great way to keep tabs on when a lightning storm will strike and how many strikes are within a storm.
While it’s easy to dwell more on tornadoes and hurricanes than on lightning, remember that it is the second- leading cause of death from weather-related occurrences. Be safe when thunder roars: Get indoors!