Know Your Surge Protection Terminology

Picking the right surge protectors for the valuable electronic equipment you depend on throughout your organization can be a challenging process. The first step is having a thorough understanding of what type of surge protection is necessary for each of your systems, and what devices can provide the protection you require.

Learning the terminology can help you to make an informed decision about which surge protectors will provide optimal protection for your devices and give you peace of mind that they will continue to operate and not be damaged in the event of a surge or spike in power.

Here is a helpful glossary for your convenience. The terms listed below are used often on datasheets and other product descriptions, and will give you a better understanding of how individual surge protectors operate.

• Clamping level. The clamping level describes the maximum voltage level that will cause a surge protector to turn on and begin diverting the surge energy away from your connected equipment.
• Ground refers to any electrical connection to the earth, either directly, through a facility ground network, or through other means, such as a driven ground rod.
• Joule rating. The joule rating tells you how much energy the surge protector can absorb before it fails. There is no industry standard for joule rating—no two manufacturers rate their devices the same way. A more definitive measurement standard is Amp rating, which measures a device in maximum amps, which makes it easier to do an apples-to-apples comparison to other surge protectors.
• Let-through voltage. Let-through voltage is the amount of electricity that a surge protector will allow to pass through to the protected devices. The better the surge protector, the lower the let-through voltage. 
• MCOV. MCOV, or maximum continuous operating voltage, is the highest amount of voltage the device will allow to pass through continuously.
• MOVs, SADs, and GDTs. Common components (metal-oxide varistors, silicon avalanche diodes, and gas discharge tubes) used in surge protection devices to divert surge energy away from the connected equipment.
• Response time. Response time is the amount of time it takes for the surge protection device to turn on and start diverting energy. Surge protection components typically have a reaction time 100 to 1000 times faster than the duration of a surge event. 
• Underwriters Laboratories, or UL, is the regulating body and safety agency for surge protective devices.

Becoming familiar with these terms when choosing surge protection devices for your vulnerable systems will help ensure that you choose the device that works best with your system. When you are making your purchase decisions, you should ask your sales professional for clarification to be sure you understand exactly what you are choosing and why it is the best choice for your needs.