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FAQ 4: What are Surge Suppressors?

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FAQ 4: What are Surge Suppressors?

ee surge suppressorsSurge suppressors (also known as surge protectors) are devices for protecting electronic equipment in homes and businesses. In commercial and industrial applications, where they protect entire panels, they are sometimes known as transient voltage surge suppressors (TVSS). Their main function is to limit sudden high voltage inputs (called “spikes”) and stray electrical signals not intended (“trash”) to provide “cleaner” power—i.e., steadier, more consistent voltage.


Unless you like playing Russian roulette with your power, yes. Lightning strikes, power surges from or outside the power company, or faults within your own building can take out electronic components in TVs, computers, circuit boards in newer appliances, etc. in a heartbeat. All of a sudden, it’s “not working”—and you won’t even know what hit you.


You can get individual strips (like those in the top image) for protecting individual computers or home theater systems, but usually it is more cost effective overall to protect the entire home with a unit like that in the bottom image. Some manufacturers include insurance protection, but be careful and do your homework—some are restricted to their own products as far as warranty coverage. Be sure the installation is done correctly—by a professional if that is stipulated by the manufacturer. When in doubt, call reputable electrical supply houses and electrical contractors, but be aware that they also may represent specific product lines and be limited in that way. Shop around. Check out online reviews. Ask your friends and family.


Unless you are an electrical engineer, the primary thing you need to know is that they protect your expensive equipment by limiting (“suppressing”) harmful voltage spikes. Beyond that, it is best to consider the main factors in choosing the right suppressors. These are:

  • CLAMPING VOLTAGE: How high does it let voltage go? The lower the better, but it is a trade-off between protection and life expectancy—the better the protection, the less likely it will survive higher spikes.
  • JOULES RATING: This is a measure of the capacity of the device to absorb a single surge and survive—but this is something difficult for a layman (and even competent electricians) to understand adequately.
  • RESPONSE TIME: How quickly does it work? Is it quick enough, and how often?
  • STANDARDS RATINGS: There are organizations (like UL, the best-known) that test, evaluate, and publish ratings. This is probably the best way to evaluate quickly.


Long story short: Trust the experts. Find out who they are and get their opinions. Call someone who KNOWS electricity, and someone you TRUST for advice.

—Ken Stewart, Easley Electric Inc.
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