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Lightning protection

Why lightning and surge protection?


To find oneself in the dark or stuck in an elevator after a lightning stroke is not amusing. It is really annoying when electrical devices get disrupted. But normally these devices are easily replaceable in a private household.

Computers are far more sensitive to such events. Nobody likes to lose the digital photos of the recent holidays, the collection of games or all the correspondence.

Surges may have other reasons too. A failure within the power grid of the energy supplier is only one possible cause of an outage. More often then not the reason lies inside the building, e.g. when somebody trips over a cable pulling out the plug unintentionally. The result is always the same – the computer gets cut off from its power supply in the midst of operation, which may lead to a data loss.

This means that the working data stored in the RAM, the "short-term memory", will definitely be lost. When the outage interrupts a writing operation on the hard disk, the "long-term memor" of the computer, the data may be destroyed or corrupted.

 

Lightning generates high voltages

The loss of power supply is the lesser of two evils. Far more dangerous is an overvoltage on the power or telephone lines. Let us take a look at a thunderstorm: Up to a radius of 1.5 km from the point where a lightning strikes the ground it induces high voltages in the cables, exceeding many times the normal 240 volts.

This surge travels through the line network, via the house distribution box, the broad-band cable or even through the telephone wire into the buildings and further on into the apartments. Often the power supply units or electronic components are not able to withstand these surges. They may burn downright due to these surges. This is visible on the printed circuit board (PCB) and one can smell it from the outside. Chips inside the computer are ruined and the hardware is defective.

In principle all devices with external power supply are in danger, from the espresso machine to the hair-dryer and the toaster. To protect all of them individually would be an immense effort. But the most valuable and sensitive devices like computers and the internet connection can be protected by a combined surge protection, a so called "combi-deflector".

(source: wdr5/2006)

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