Power surges (during lightning storms, for example) can be very damaging for devices left plugged in, even if they’re switched off. Here, we’ll show you how to make sure you have the right overvoltage protection.
What is overvoltage?
The term “overvoltage” means a voltage in an electrical system which is so high it exceeds the tolerance range of its nominal voltage. The mains voltage used in Europe is 230V (plus / minus 23 volts). Heavy current, usually needed in the kitchen for connecting appliances, is 400 volts. A lightning strike will lead to overvoltage, damaging these devices and installations.
Causes and dangers of overvoltage
In a thunderstorm, between the negative charges in the lower part of a thundercloud and the positive charges on the ground, electrical voltages can often exceed ten million volts. If it reaches an “overflow”, then a current of around 300,000 Amps flows through. In the best case scenario, this will blow the fuse.
Depending on the severity, a lightning bolt will also damage the building structure and installations of the house. The high heat development can even start fires. Plugged in devices, such as computers, household appliances or electronic heaters are likely to fall victim to the surge voltage. This causes loss of data, or the device to break completely, in the worst cases.
Can I get insurance to pay for these damages?
You can insure yourself against thunderstorm damage to your house and your electrical devices. A standard residential building insurance carries the costs of damage by fire, storm and lightning. The contracts often regulate exactly what type of overvoltage protection must be present; an external lightning conductor, for example.
A household insurance covers damage to all contents of your house, such as furniture, carpets, fixtures and electrical appliances. Newer policies sometimes include surge damage, however ensure you check as it doesn’t come as standard. A household contents insurance is usually not liable for lost data.
So, if lightning hits and the hard disk of a computer breaks, the insurance can pay for a new hard drive. However, they will not cover costs for the restoration of data or the recovery of software, documents or photos.
Our top tip: make sure you back up your data and keep receipts for all hardware and software.
Types of overvoltage protection
There is a difference between external and internal overvoltage protection.
- External lightning current arresters (“lightning arresters”): In the EU, this lightning protection is defined by the EN 62305 standard. The external lightning protection must be in line with the internal lightning protection for the building.
- Surge arrester (surge protection device type 2): This protection is usually found in the floor distributors in buildings. It limits the remaining overvoltages in a lightning strike to less than 600-2000V.
- Special equipment, e.g. a surge protector (overvoltage protection device type 3): This protects sockets and plug-in connections. It reduces the remaining overvoltages to about 230V.
Surge protection: products for retrofitting
The large number of built-in conductive parts in houses, and the ever-increasing amount of technical equipment, mean lightning can be very dangerous. Switches, routers, firewalls, xDSL modems, ISDNs, Notebooks, PCs, TV sets and multimedia devices; everything needs protecting.
This begins with the socket. The Super-Solid 8-way socket outlet from BRENNSTUHL offers eight connections and secures your devices with overvoltage and lightning protection up to 4,500 Amps. It is extremely robust, made from shatterproof polycarbonate.
The practical BRE 1506996 Surge suppressor, 230 V surge protection adapter offers overvoltage protection up to 13,500 Amps, and has a built-in child safety device.
Network cables are particularly dangerous because they make perfect conductors. The ALLNET surge protection can help here. Place it between your network cable or xDSL/ISDN connection and the device to be protected.
For optical networks, the Netzwerk-Überspannungsschutz is an Ethernet coupler to protect against surges. When used in existing networks with conventional wiring, the interface is coupled by an optical bridge and galvanically insulated. The optical transmission is also immune to the interference of stray electromagnetic interference.
If you tend to connect USB devices to your PC, you should also think about lightning protection for this. For example, if lightning hits a high-mounted spotlight during a garden party, this could destroy the DJ’s connected laptop.
When controlling lighting, electrical systems or machines via USB, galvanic isolation will provide necessary protection for the computer.
Image: Adobe Stock
