🌀 A surge protection device (SPD) or simply a surge protector is a device used to ensure protection against transient surges. It is used to protect the household and commercial applications from voltage transients. It is connected in parallel to the load it has to protect.

🌀A transient surge is a sudden increase in power (voltage and current) that lasts for a few microseconds. lightning ⚡ is the major external reason for transient surges.

🌀SPD are devices used to ensure protection from the above-stated dangers caused by transient surges. Surge protectors connected in parallel have a high impedance. This impedance drops as transient voltages appear in the system so that the current can be driven to the earth through them.

🌀 SPD types: The IEC 61643 standard defines 3 types of surge protective devices for low voltage electrical system.

🕯 Type 1 or Class I: Type 1 SPD can discharge strong lightning current and are installed in the main electrical switchboard when the building is protected with a lightning protection system (lightning
rod, down conductor and grounding).

🕯 Type 2 or Class II: These surge protective devices (SPD) is designed to discharge current generated by indirect lightning hit which causes induced overvoltage on the power distribution network. Typically, they are installed at the main distribution switchboard.

🕯 Type 3 or Class III: Type 3 SPDs are designed to reduce the overvoltage at the terminals of sensitive equipment and therefore has a relative limited discharge current capacity.