A surge protective device (SPD) is an appliance or device intended to protect electrical devices from voltage spikes in alternating current (AC) circuits. Lightning that hits a power line can give a spike of over 100,000 volts and can burn through wiring insulation and cause fires, but even modest spikes can destroy a wide variety of electronic devices, that happen to be plugged in at the time. Typically the surge device will trigger at a set voltage, around 3 to 4 times the mains voltage, and divert the current to earth or release it as heat.
In addition to CLC/TS 61643-12, the technical report in PD CLC/TR 50656 describes the principle of erecting SPDs to be connected to 50 Hz a.c. power circuits, rated up to 1 000 V r.m.s. in conjunction with Class II equipments. In addition to PD CLC/TR 50656, PD CLC/TR 50656 gives specific guidance for SPDs intended to be installed in class II equipments.
PD CLC/TR 50656 on SPD class 2 standard is useful for:
SPD is designed to limit transient overvoltage of atmospheric origin and divert current waves to earth, so as to limit the amplitude of this overvoltage to a value that is not hazardous for the electrical installation and electric switchgear and control gear.
SPD eliminates overvoltage
The Type 2 SPD is the main protection system for all low voltage electrical installations. Installed in each electrical switchboard, it prevents the spread of overvoltages in the electrical installations and protects the loads.
The sections on SPD assembly one SPD or a set of SPDs, in both cases including all SPD disconnectors required by the SPD manufacturer, providing the required overvoltage protection for a type of system earthing, SPDs connected to PE for the protection of Class II equipments, and SPDs not connected to PE for the protection of Class II equipments has been discussed in thorough details in PD CLC/TR 50656. Using PD CLC/TR 50656 guidelines, you can learn more about the principle of erecting SPDs to be connected to 50 Hz a.c. power circuits, rated up to 1 000 V r.m.s. in conjunction with Class II equipments. PD CLC/TR 50656 guidelines enable you to provide your operators with a hazard-free working atmosphere and your customers with safe, stable, and reliable services.
CLC/TR 50656:2016