Overvoltage protection ensures that devices and systems connected to the power supply are not damaged if the voltages are too high. Such high electrical voltages can occur, for example, due to lightning strikes or electrostatic discharges. Devices that are not protected by overvoltage protection can be damaged or destroyed in such a case.
Overvoltage protection protects all electrical equipment in the connected circuit so that lightning or electromagnetic discharges do not damage them. Such overvoltage protection can be done both for the entire course – and thus for all linked devices – as well as individually for individual devices. Using corresponding multiple sockets with integrated overvoltage protection, for example, all devices can be secured at the IT workstation in the home office.
For homeowners, it is recommended to go through the electrical equipment and to consider whether a system is particularly at risk. These include, for example, outdoor antennas, long data lines, and lines near power transmission facilities. In the case of particularly expensive devices, the safety achieved by overvoltage protection usually outweighs the cost of acquisition and installation.
It is essential to observe the so-called protection circuit principle: the area within a mental protection circuit must be wholly secured because overvoltage protection is only valid if all accesses to the system are obtained.
Defects caused by overvoltage after lightning strikes occur most frequently: According to the Federal Association of the Energy and Water Industry (BDEW), the number of lightning strikes have been increasing for years. At the same time, the number of electronic devices has multiplied. In total, millions of euros of damage a year occur in Germany, which could have been avoided by adequate overvoltage protection.
Operation of an overvoltage protection
As soon as a so-called voltage peak (a high-voltage pulse up to 6 kV) occurs, it is discharged via the overvoltage protection directly to the neutral conductor of the circuit. In the derivation of such an average amount of energy, the function of the overvoltage protection is wholly retained.
If a higher amount of energy is dissipated, a temperature increase occurs at the switching component (varistor, VDR). In typical operation, the resistance of a varistor is considerable, while in the case of overvoltage, the resistance becomes very small, almost instantaneously, and dissipates charge. This protects switch boxes as well as data lines or antennas.
The protector against voltage surges derives the excess current to ground.
The function of the protector against power surges is to stop this situation if it is produced, being able to do it in two ways :
- Fuses: Many surge protectors have an integrated fuse, which is tared for a certain intensity. When the current that runs through the electric circuit reaches a specific value, the fuse melts and does not allow the electric current to reach the components.
- Derivation: other overvoltage protectors, what they do, is to derive the electrical current that exceeds specific parameters to the grounding of the plug to which they are connected. In this way, the connected components are protected.
Very broadly speaking, the surge protector works like the general switch in the lightbox of your home. The difference between the two is that the one in your house is tared for much higher amperage than the one for which the protector is usually tared.
Installation of surge protective devices
The overvoltage protection is connected in parallel to the circuit to be protected. Ideally, a homeowner secures the entire electrical circuit, including the control box, all devices, data lines, etc. directly during construction.
Old buildings can be retrofitted with overvoltage protection, but where appropriate, the security of individual components is more useful than overvoltage protection of all devices. For the so-called terminal protection, usually single or multiple socket strips are used with an integrated protection circuit.
For proper installation of the overvoltage protection, it is advisable to consult an electrician. This can also plan the surge protection of the entire house according to the needs of the owners. The costs are usually manageable: individual surge protection switches cost from 60 euros. Added to this are the costs for installation by a specialist.
Is overvoltage protection advisable?
Surge protection protects electrical and electronic equipment from the excessive voltage that would destroy or damage it. These include, for example, a lightning strike as well as electrostatic charging or voltage curves in photovoltaic systems.
An overview of the benefits and what to keep in mind:
- Protection of all switch boxes, devices, power and systems against overvoltage
- Avoidance of costs for device repair or acquisition of new equipment
- Individual terminals can be individually secured by adapter plugs or socket strips with integrated overvoltage protection.
To be considered
- Proper installation by an electrician is recommended. Most of the costs are profitable from a single failure due to overvoltage.
- Insurances usually do not pay for destroyed devices due to a lightning strike or electrostatic charge.