How can I protect my home and appliances against lightning?

Every year around 250,000 lightning strikes occur over Belgium. In some cases, these electrical discharges between storm clouds and the earth can cause serious damage. Not only to buildings and structures, but also to people, equipment and devices.

As such, it is crucial that you know what to do in order to protect your property and appliances as much as possible.

Elementary precautions against lightning

Some points of advice and tips to follow if your home is not protected against lightning:

Rule n°1: unplug as many electrical and electronic appliances as possible if there is a storm brewing
Don’t leave them lying next to the socket, because if you do the electric current can still jump across!
To take maximum precautions, remember to check both the electric sockets and the telephone and cable television connections. You can also fit an external and/or internal protection, but in proportion to the very low risk involved, these two measures work out fairly expensive. However, pulling the plugs of all appliances out of the sockets is practically impossible. Just think of built-in devices such as your fridge, dishwasher, oven etc. Of course you can switch off all circuits with the electrical mains switch, but by doing so you will be also without lights! Furthermore, chances are you are not even home during a thunderstorm…
A tip: make sure that your fire insurance also covers damage caused by overvoltage!

Lightning conductor and central overvoltage conductor

If you want to take it to the next level, you can protect your home, electrical installation and appliances with a lightning conductor and an overvoltage conductor.

Level 1: external protection

A lighting conductor guides the lightning to the earth and protects your home against damage and fire caused by direct lightning strikes. They can be seen on towers, masts and tall buildings. They are reasonably expensive (sometimes as much as several thousand euros), they have to be installed by a specialist and they need regular maintenance.

Level 2: internal protection

A lightning strike at a distance can, however, cause indirect damage, as it creates shock waves and overvoltage which can spread:

by conductivity: this usually occurs if a surface cable (for electricity, telephone or cable television) is hit by the lightning and carries the overvoltage to the home it serves. Fortunately there are very few surface cables in Brussels.
by induction: the overvoltage spreads via electromagnetic radiation and touches an electric circuit to which electrical and electronic appliances are connected.

In the event of an indirect lighting strike, a central overvoltage conductor fitted to the electric circuits will guide the electric overload to the earth and hence protect the entire installation. A conductor like this costs between EUR 500 and EUR 1,000 and must be installed by a specialist.

However, the central overvoltage conductor does let residual current through and this can harm electrical appliances susceptible to disruption, such as televisions, computers, sound installations and telephones.

These appliances and all the related equipment can therefore also be protected separately by connecting them to a (multiple) power socket with overvoltage protection. But these sockets are not as effective against lightning strikes as the manufacturers claim... In any case, they are insufficient if they are used as the sole form of protection.

A limited risk in Brussels

If you live in a city like Brussels, the risk that your home will be directly hit is, however, very small. Why is that?

Lightning always seeks the easiest way to reach the earth and preferably comes down via high structures (bell towers, skyscrapers, etc.), metal projections (beware of galvanised chimneys) and overhead lines.

In urban areas there are a lot of high buildings, but also very few isolated homes and surface cables. Consequently, there is much less risk of damage or fire caused by lightning in the town than in the countryside.