Overvoltages are up to 20 times higher than normal operating voltages – Equipment at home is vulnerable to damage


10.12.2019 at 14:12
Overvoltages can be caused by lightning strikes that hit a property directly or close to a property. Lightning overvoltages can travel to a property from the supplying electricity network, outside cables of the property, telephone lines, aerial leads, and data cables. Overvoltages and the damages they cause can be prevented with the correct overvoltage protection.

Deploy an overvoltage protection

The requirement for overvoltage protection is relevant mainly in rural areas and areas outside urban environments. Overvoltage protection is required in areas where the supplying electricity distribution network is primarily comprised of overhead lines. 

In urban areas with an underground electricity network, the risk of dangerous overvoltages is small. Protecting safety and data communications systems in cabled urban areas is nevertheless recommended. Existing properties that are at risk of overvoltages and do not have overvoltage protection can be protected afterwards, which is also recommended.

How is overvoltage protection implemented?

The overvoltage protection of a property can be implemented with surge arresters installed in main switchboards and fuseboards. The protection can be supplemented with terminal-specific protectors that are installed directly in sockets. To ensure the functioning of the overvoltage protection, it is important that the earthing systems of the property are also in order.

Overvoltage protection in meter reading centres built by Caruna

Caruna estimates the need of overvoltage protection in new connections where Caruna has built a meter reading centre. The estimation is done using methods described in the relevant standard, and when necessary we will also install surge arresters in the meter reading centre. The overvoltage protection installed in a meter reading centre can be supplemented with surge arresters installed in main switchboards and fuseboards and terminal-specific surge arresters.

Detecting and changing malfunctioning surge arresters is the responsibility of the property owner. Surge arresters can only be changed by an authorised electricity contractor.

More information about overvoltage protection

If you have questions about overvoltage protection, please contact an authorised electricity contractor. Please also remember to ensure that e.g. your antenna and solar power system have been protected against overvoltage.

For more information about overvoltage protection, see e.g. the Finnish Safety and Chemicals Agency (Tukes) website (in Finnish).

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