How do Surge Protectors Work?

By Nicole Tinkham

Pictured: Innovera Surge Protector, 6 Outlets

Simply put, surge protectors (also called surge suppressors) protect devices from surges, or sudden spikes in voltage. They can be plugged into your ordinary electrical outlet with the device that needs protecting plugged into the surge protector. While these often resemble power strips with several outlets, it’s important to realize that not all power strips are surge protectors. Now that we understand the basics, let’s move on and discuss the technical aspects of surge protectors starting with defining a surge.

What is a surge?

A surge is a high voltage electricity flow above the standard 120 volts. There are two ways to classify a high voltage flow: a surge and a spike. An increase that lasts three nanoseconds or more is considered a surge while a spike only lasts one or two nanoseconds. When a surge or spike occurs, it can cause damage to the device, if not completely destroying it – which is why surge protectors are so important!

How a surge protector works

A surge protector acts as a normal power strip until there is a surge that goes above the accepted level. When this happens, the excess energy is diverted away from the devices plugged into the protector and goes into the grounding wire (within the surge protector). In most surge protectors, the part that diverts this excess energy is called a metal oxide varistor (or MOV) which connects the hot line with the grounding line. Even when the MOV diverts the current, other machines plugged into the surge protector can still run on the standard current.

Do you need a surge protector?

If it’s for a computer, we definitely recommend a surge protector. Computers are filled with voltage-sensitive parts which can be easily damaged with a power surge. This can damage your computer and wipe any stored information at the very least. As we all know, computers and replacement parts can be pricey so investing in a surge protector is a smart choice. You may also want a surge protector for any other expensive devices that you would not want to replace in the event of a power surge. Surge protectors are not necessary when it comes to smaller items though, like lamps. The worst a power surge can do is burn out your light bulb.

Buying a surge protector

When purchasing a surge protector, you have many options. One thing to look for is an indicator light. Sometimes the MOV can burn out in which case your surge protector is no longer doing its job. An indicator light tells you that the surge protector is functioning properly. Other options include the number of outlets, the level of protection, cord length, and more.


Surge protectors often come with 4, 6, 8, 10, and 12 outlets. It’s important to consider how many outlets are needed as a 12 outlet strip would be a waste if only 2 or 3 outlets are being used. Transformer plugs are often wider than the standard plug so keep this in mind when purchasing a surge protector. Many will be set up to accommodate this larger size without blocking other outlets.


Think about what you need to plug into a surge protector. Consider telephone lines and computer cables. Many surge protectors include these types of outlets.


Electrical energy is measured in joules. A surge protector’s joule rating lets you know how much energy the surge protector can take. When looking through the catalog or on Keeton’s website, look at the joule rating. The higher the number, the more protection it provides. Joule ratings can range anywhere from 140 to 3,000+.


To ensure your surge protector will reach devices needing protection, pay attention to the cord length. You will notice a range of 2ft to 25ft.


If your surge protector does fail resulting in damaged devices, the insurance covers the replacement of these devices. Make sure the amount of insurance on the surge protector is enough to cover your equipment!


Another thing to pay attention to is the manufacturer’s warranty. Some surge protectors offer a limited one-year warranty while others offer a lifetime warranty.


Style plays a big part in your options and we’re not talking about color choices (which are limited to various shades of gray, black, and white). See below for some awesome styles for extra convenience.

ECO-Surge Energy-Saving Surge Suppressor: Reduces energy waste, saving you up to $40 a year!

Double-Sided Surge Suppressor: A space-saving surge protector with a right-angle plug.

Direct Plug-In Surge Suppressor: Provides direct plug-in without a cord.

Travel-Size Surge Suppressor: A compact surge protector ideal for portable devices such as laptops. USB ports also allow for convenient charging for cell phones and other portable devices.

Conserve Surge Protector with Timer: Has a built-in timer that automatically shuts off for devices that don’t need constant power (2 outlets are always on).

Pivot Plug Surge Protector: Outlets pivot to accommodate AC adapters.

SmartSockets: Color coded outlets provide easy identification.

Mighty 8 Surge Protector: This 8 outlet surge protector is surprisingly compact, accommodating 5 AC adapters.  

Metal Split Surge Protector: This one comes with two strips that can spread up to 1 ½ feet apart.

Wall Mount Surge Protector: This surge protector can be wall mounted, saving floor space.

Surge protectors may not seem necessary – until your equipment gets damaged due to a power surge. Play it safe and invest in a surge protector, using this blog as your guide. Feel free to give us a call (941-747-2995) or stop in for further assistance!

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