Surge Protective Devices (SPD)

Surge Protective Devices (SPD) are used to protect the electrical installation, which consists of the consumer unit, wiring and accessories, from electrical power surges known as 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. Equipment with sensitive electronic circuitry can be vulnerable to damage by transient overvoltages.

What is Type 1, Type 2, and Type 3 SPD surge Protective Device?

Type 1 Surge protective device: Type 1 SPD, also known as class l sPD, installed at the service
entrance of an electrical system, is designed to withstand high-energy surges, protecting severe
transient events for equipment and circuits within the electric system.

Type 2 Surge protection device: Type 2 SPD, or Class ll SpD, is typically installed downstream
from type 1 or at distribution panels. lt offers protection against residual surges and lower-energy
transients, working in combination with the type 1 surge protective devices.

Type 3 Surge protector device: Type 3 SPD, or Class ll spD, is installed at the point of use, near
or within significant or sensitive individual devices, providing accurate and localized surge
suppression against low-energy surges that is relatively minor but may enough to damage
specific equipment as well.