How lightning strikes a house

Lightning strike in the house: what happens if lightning strikes?

How is lightning created? Probably the most spectacular celestial event - besides solar and lunar eclipses - that can be observed with the naked eye in this country is the lightning that strikes through the dark sky during a thunderstorm like a trembling, shining bright arrow, charged with immense ones Electricity charges. What can also be observed with the bare eyes in thundering storms is unfortunately often also the lightning strike, when it happens that the lightning strike sets a roof on fire in a matter of seconds.

House owners and insurance companies are well aware of the devastating effects of lightning and lightning strikes, and people also believe that they know what to do to protect themselves in the event of an approaching storm front. Because in the event of lightning, a person can Burn damage suffer to the point of death - it is life-threatening. It is all the more important to have the right knowledge of how to behave in incidents that can happen out of the blue.

In the following we want to separate myths and reality and see how a thunderstorm with lightning and thunder actually arises, what lightning damage can occur and how it can really be averted - without saying wisdom, only fact-based and checked by an expert, the "lightning-smart" about Risks and educate opportunities.

What is effective protection against lightning strikes in open areas - and in residential areas?

Myths and reality - when it comes to the subject of "lightning strikes" they are extremely close, because the approach of a thunderstorm, strong rule and hail have been around since ancient times threatening stormsthat intuitively scare us. It is not far from the primordial fear of a thunderstorm to superstitious reservations and supposedly safe tips, but unfortunately these old ideas are of little help in concrete incidents with lightning strikes, and that's why we want to separate myth and truth here.

Almost everyone in Germany knows the old adage "You have to look for the beeches, you have to give way to the oaks" as a prevention against fire and for lightning protection, because our ancestors assumed that lightning would basically strike oaks and that one under beeches is supposed to happen Lightning is protected. This is not true because, statistically speaking, lightning has often struck other tree species - so if you are in the forest or outdoors while a thunderstorm is approaching, you shouldn't keep walking stop and crouch. The crouched posture reduces the potential target area for a lightning strike, which means protection.

Basically, one is by no means safest looking for protection under any trees, but rather within closed surroundings - the environment (house, car) physically acts like a Faraday cage and conducts the lightning current into the earth. The physicist Michael Faraday has namely in his illustrative model "Faraday cage" showed how electrical charges continue in space: they conduct around closed spaces that are surrounded by voltage on the outside like cages, but without electricity on the inside. That is why you are safe from lightning strikes inside a car or in your own home - provided the latter is equipped with a lightning protection system. Knowing this physical fact can save lives!

You shouldn't look for the beeches, but when a thunderstorm is approaching you should crouch down immediately. So it is wrong to - remembering vaguely old proverbs - get out of the car during a sudden thunderstorm in the forest, because it is better to stay in the car. In inhabited areas, when a thunderstorm is close by, the best precaution is the lightning protection system on your home.

How lightning protection systems are constructed

In popular parlance, the modern lightning protection system is often simply called "lightning rod". A lightning arrester basically consists of three elements that divert lightning currents: internal and external lightning protection and earthing. This three-component system structurally exists in all versions of lightning protection systems, from the simplest to the most technically sophisticated.

The external lightning protection consists of an interception system that diverts the current from the roof of the house into the earth. The internal lightning protection system consists of a fuse for electrical devices Overvoltage damage. The earthing last, as the name suggests, leads the current into the ground and consists of corrosion-free cables, usually made of copper or other highly conductive material.

An interception device / interception system installed by a specialist and a Earthing system for protection against overvoltage - these are necessary precautions to avoid incidents caused by lightning strikes. So-called lightning protection systems can be installed when a new house is built, or the home can be retrofitted - a safe investment for the residents.

Most homeowners are concerned with protecting themselves against fire when it comes to lightning protection. In the case of lightning damage, insurance companies attach great importance to the fact that insurance cover already existed at the time of the incident. Subsequent protection against lightning strikes is factually and legally not possible. Anyone planning ahead should therefore take out the insurance policy in good time.

What happens inside or outside when lightning strikes?

In the worst case, fire fighters have to go out to extinguish the fire if the lightning protection has failed and the home is on fire. However, a lightning strike does not always set the roof structure on fire - so-called “overvoltage damage” inside the home, which looks far less spectacular, can also severe consequences for the entire home electronics and, above all, for the residents.

Modern households today are technically highly equipped and have a wide electromagnetic field with multiple circuits, from telephone lines to the stereo system to the computer, and the lightning that has struck can continue on these lines. Easily arises through lightning strike an overvoltage in power lines and sockets that paralyzes technical devices and forwards lightning current with a high voltage charge to the human body by means of an electric “shock” if it comes into contact with it. Safety precaution in the event of a thunderstorm: unplug the household and do not touch electrical devices!

What the expert advises

Basically, the immense voltage charge that can strike power lines in the house when lightning strikes, creates a dangerous overvoltage. In the case of overvoltage damage to electrical appliances in the household, electrical engineers differentiate between short circuits and damage caused by contact voltage that can affect the resident. Simple Surge protection devices or complete surge protection systems help reliably to protect the devices in the house - and people from electric shock.

The VDE (Association of German Electrical Engineers) recommends leaving the outdoors during a thunderstorm and avoiding any risk of lightning strikes or objects struck by lightning in the immediate vicinity. The weather service is not always reliable today because, despite a high level of meteorological expertise, not every storm can be forecast.


Thunder and lightning are among the storms that people spontaneously fear - and this fear has resulted in sometimes nonsensical weather rules that, in an emergency, do more harm than good. Knowing a few physics facts is more helpful than avoiding the oak trees in the forest - anyone who is surprised by a bad weather front is safest in closed rooms, in the car or in the house. In the house, however, you have to have one Lightning protection system installed to prevent the sudden lightning strike from going through the roof and setting off flames or causing overvoltage damage to electronic devices and sockets inside.

Article image: marketanovakova /

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