Historically this has not been an issue within domestic installations but more recently, installations are changing with the advent of new technologies such as electric vehicle charging, air/ground source heat pumps and speed-controlled washing machines have made transients much more likely to occur within domestic installations. Man-made transients appear due to switching of motors and transformers, along with some types of lighting. Transient overvoltages can be either naturally occurring or man-made. Transient overvoltages are defined as short duration surges of electricity which occur due to the sudden release of energy previously-stored or induced by other means. Items supplied by different manufacturers should be confirmed for compatibility, the installer and manufacturers of the devices are best placed to provide guidance on this.
Where multiple devices are required to protect the installation, they must be coordinated to ensure correct operation. They must only be installed as a supplement to Type 2 SPD. Type 3 SPD installed close to the protected load.(Combined Type 1 & 2 SPDs are available and are usually installed in consumer units).Type 2 SPD installed at sub-distribution boards.Type 1 SPD installed at the origin, e.g.There are three different types of Surge Protective Devices: It is important to remember that protecting the electrical installation alone and not the other services could leave another route for transient voltages to enter the installation. SPDs are usually installed within the consumer unit to protect the electrical installation but different types of SPD are available to protect the installation from other incoming services, such as telephone lines and cable TV. The effects of a surge can result in either instant failure or damage to the equipment only evident over a longer period of time. Equipment with sensitive electronic circuitry can be vulnerable to damage by transient overvoltages. They are also used to protect sensitive electronic equipment connected to the installation, such as computers, televisions, washing machines and safety circuits, such as fire detection systems and emergency lighting.