SPD is an electrical device typically installed in power distribution panels, process control systems, for the purpose of protecting againts electrical surges and spikes, including those caused by lightning. A surge protector attempts to limits the voltage supplied to an electric device by either blocking or shorting to ground unwanted voltages above a safe threshold.
- Class B : Lightning Surge Protection
- Class C : Switching surge Arrestors
- Class B + C : Lightning cum switching surge protection.
- Class D : Data & Telecom Surge Protection.