Due to the constantly growing number of electronic devices in the household, lightning and surge protection is becoming increasingly important. A trend that only serves to reinforce the move towards smart homes. While simple electrical equipment is relatively resistant, spikes in voltage in the power supply can easily destroy electronic circuits. Power socket strips, intermediate connectors and adapters promise protection.
Where does the surge come from?
When you plug the mains plug of an electrical device into a power socket, you expect that this supplies power with the appropriate AC voltage of 230 V. Power generators control voltage in the power supply accordingly, but you are creating interference in this system solely due to the fact that you are switching power consumers on and off as required. But this interference is usually so low that it has no practical implications.
High spikes in voltage mainly occur when switching electric motors on. Inrush current is therefore limited in large machines. Start-up current limiters such as intermediate connectors also exist for household appliances such as washing machines. In contrast to surge protection, they eliminate a cause of spikes in voltage in your power supply. But they do not protect you from surges caused by other devices or those which reach your network from outside via your home connection. They can be especially strong during thunderstorms.
How does surge protection work?
Surge protection can be implemented in several ways. Technically it is based either on the fact that a specific component “burns” excess voltage and thus electrical power. Suitable components are, for example, metal oxide varistors, voltage-dependent resistors that only become conductive when there is a surge.
The heat created when the surge is eliminated is generally low because surges are usually only short-term. However, if a varistor is operated for long periods of time with excess voltage, it may even cause a fire.
In standard power socket strips and intermediate connectors, gas arresters that work in a similar way to flash tubes in electronic flash devices therefore supplement integrated surge and lightning protection. This removes the surge in a controlled flash.
The second kind of surge protection prevents overheating by ensuring that the power supply short circuits in the event of excess voltage and so the upstream mains fuse triggers.
How good is surge and lightning protection?
The important criteria to bear in mind when evaluating surge protection devices such as adapters, intermediate connectors and power socket strips are response time and maximum current that can be derived. High currents with up to several kiloamperes (kA) mainly occur in the event of a lightning strike in the power supply.
A short response time in the nanosecond range is important because even very brief spikes in voltage can damage electronic circuits. Normal fuses react too slowly in this respect.
Image source: Fotolia / 43569960 / Gewoldi
