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Sine Wave Technologies
559 Davidson Gateway Suite 201 Unit 8
Davidson, NC 28036




Bruce Watson
Managing Member
Julie Hannon
Inside Sales

How to Select a Surge Protection Device  

While technology and the complex design of surge protection devices (SPDs) has improved, the amount of confusion over their specifications has not. So, how do you select the proper device for your application? The best course of action is to call our office and let us assist you; however, following these parameters will help you make an informed decision:

When selecting a device:

  • Make sure you know the system voltage and where the SPD’s should be installed. If the application leads to a series (vs. parallel) device, make sure the current rating for the SPD exceeds the system’s current rating including in-rush.
  • Understand what you are protecting against. Whether it is an internally generated transient (Category A) or direct lightning (Category C) will determine the ‘KA’ Rating.  The ‘KA’ Rating is the peak surge current (per phase or mode).
  • Understand what you are protecting. How sensitive is this piece of equipment? How critical is it to your operating process? (From a CNC Lathe to a home business PC) How costly is it to repair the equipment?

If you are reacting to past experiences, reviewing the last 24 months of power related disturbances (board failure, loss of electronics, power outages) will help in determining the level of protection needed. This will also determine if an active tracking filter (ATN) is needed.

When shopping different products it is critical that you follow these guidelines:

  1. Compare Manufacturers
    When comparing manufacturers, it is imperative that they provide the following information: IEEE C62.41 Measured Limited Voltage Chart. A1 through C3. This is the only way to compare the performance of one SPD product against another. During testing, it is highly critical that a parallel connected device have a 6” lead length to simulate actual installation. This lead length will demonstrate the true performance of the product when performing in your application. A UL 1449 test should also be listed. This will differentiate the ‘arrestor’ from the ‘suppressor’.
  2. Determine Peak Surge Current (strength of device)
    Many manufacturers provide confusing or vague information pertaining to their product specifications. The claims they make need to be backed up with proper documentation. The information collected by the manufacturer should originate from a U.L. listed laboratory and conform to IEEE, UL, and Nema standards.
  3. Determine IEEE let through voltages (the amount of excess voltage which is “let through” to your equipment)
  4. Determine which SPD is correct for your application (gas tube, silicon avalanche diode, MOV, capacitor)
  5. Review the Warranty
    Read and completely understand the warranty. Ironically, many manufacturers exclude surge related events in their warranty! This may be your biggest surprise in the process! Beware of warranties that do not cover:  lightning, “acts of God”, normal wear and tear, etc. 

Should you have a competitors surge suppression device and would like us to cross reference it to an Innovative Technology device, please call our office.  We will show you the specific comparison between the two units and will guarantee, spec to spec, the lowest price. 

Please feel free to contact us with any questions or concerns you have regarding power quality. . . And happy selecting!

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