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How do SPDs work?

SPD stands for Surge Protective Device, which is a device that is designed to protect electrical and electronic equipment from voltage surges and transients. Here is a brief explanation of how SPDs work:


SPDs are installed in parallel with the equipment they are designed to protect. This means that they are connected between the power supply and the equipment, and they divert excess voltage to ground.


SPDs typically use one or more metal oxide varistors (MOVs) to absorb excess voltage. MOVs are semiconductors that have a variable resistance depending on the voltage applied to them. When voltage spikes occur, the MOVs become conductive and divert the excess voltage to ground, thus protecting the equipment.


In addition to MOVs, SPDs may also include other components such as gas discharge tubes, capacitors, and inductors to provide additional protection against different types of surges and transients. SPD breakers come equipped with these various components to offer optimal safety and protection, catering to the specific needs of various electrical systems and appliances. 


SPDs must be properly sized and rated for the equipment they are protecting. This includes consideration of the voltage and current ratings of the SPD, as well as the maximum surge current that it can handle.


It is essential to have a reliable SPD brand installed. SPDs should be installed by a qualified electrician and should be regularly inspected and tested to ensure that they are functioning properly. By choosing a reliable SPD brand and adopting a preventative approach through regular inspection and maintenance, it is possible to safeguard the integrity of electrical systems and minimize the risks of electrical surges or failures.


Overall, SPDs provide an important layer of protection against voltage surges and transients that can cause damage to electrical and electronic equipment. By diverting excess voltage to ground, SPDs can help extend the lifespan of equipment and reduce the risk of downtime and costly repairs.

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