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What are the risks caused by lightning and the protection against them? | Legrand Mauritius

What are the risks caused by lightning and the protection against them?

During thunderstorms, lightning strikes the earth, causing physical damage to installations and deteriorating electrical and electronic equipment. It is therefore essential to install reliable systems capable of protecting people and property from the various effects generated.




When lightning strikes a building or a structure directly, it generates a very high current which passes to the ground via the chimney, the roof, the walls, etc. This current is generally between 50 and 100 kA, but can sometimes reach 200 kA, and can cause fires or even explosions.



An "external" system, commonly called a lightning rod, can protect the building by capturing the lightning current and passing it directly to the ground.



Even when it does not strike a building directly, lightning can generate surges in the building's electrical system through either the power line or the ground connection. These indirect effects can occur by conduction, by induction "loop effect" or by rising to the ground.





Surge protectors are the essential solution to protect people and property against these effects. They allow :

- avoid any risk of electrocution for the people present

- avoid any material damage or premature aging of the equipment and components of the installation

- to improve the continuity of the electrical installation

There are two types of lightning arresters

- the housing surge protector, also called mains surge protector: it protects the installation against overload and short circuit currents

- the surge protector for telephone line and communication network: installed in addition to the surge protector for housing, it protects the equipment connected to the telephone and digital lines inside the building



Legrand's advice

• For each dwelling, provide a protected lightning arrester for the switchboard and a telephone arrester.

• Set up proximity protection for sensitive equipment (computers, electronics).




As the surge protector is an active product whose components age naturally over time, it must be associated with a circuit breaker to protect it against short circuits at the end of its life.




The NF C 15-100 standard requires a lightning arrester in the following cases :

- building equipped with a lightning conductor: install at least one T1+T2 type lightning conductor, Iimp 12,5 kA

- building located in a zone with a high keraunic level and whose power supply is entirely or partially overhead

- building located in a zone with a high keraunic level when the safety of people is concerned. Examples: installation which includes a medical equipment at home, an intrusion alarm, a fire alarm, a technical alarm against domestic risks, etc






Legrand solutions

With our range of surge protectors, you benefit from solutions adapted to all types of installations and all levels of risk.






Good to know!

We offer solutions with integrated short-circuit protection to ensure continuity of operation, reliability and safety. Surge protectors with integrated protection also simplify and secure the installation and maintenance.




Several criteria must be taken into account when choosing a lightning arrester: type of building concerned, keraunic level, type of network line, equipment present, etc.