Do Surge Protectors Really Work? Here’s Everything You Need to Know!

what do surge protectors help prevent in the workplace

Almost everyone knows that power fluctuates constantly. Although most appliances and electronic devices are designed to handle slight surges and dips in electricity voltage, most will sustain damage if the voltage spikes are too high. In such cases, the sudden hike in voltage can fry circuit boards. 

Surge protectors will protect the internal components of electronic equipment and home appliances when the voltage rises far beyond what these devices can accommodate. 

What is a Surge Protector?

Some people think that a surge protector is no different from an ordinary power strip; worse, they may assume that a strip will protect their electrical devices from a power surge. Let’s differentiate the two, so you’ll better understand what surge protectors do. 

A surge protector may look like a power strip, but it does more than allow you to plug several electrical devices and appliances into one electric outlet. The surge protector has a more critical function, which is to protect your electronics from the excess voltage in the line that occurs due to certain events, such as a lightning strike. 


A surge protector isn’t designed to work forever. It’s bound to fail somewhere down the road. Unfortunately, knowing when it wears out can be challenging, which means that you could be lulled into a false sense of security. You might think your appliances and electronics are protected against power surges when, in fact, they aren’t. 

Surge protection devices can overheat, resulting from damaged metal oxide varistors and semiconductors in the unit. Overheating affects the performance of the surge protector, which can lead to its failure. 

To play it safe, replace your surge protectors every 3 to 5 years to ensure they continue keeping your devices safe from damaging spikes in voltage. 

How Do Surge Protectors Work?

Surge protectors work by pulling the electrical current from one outlet and passing it to the various devices that are plugged into them. What protects the electronics and appliances is a metal oxide varistor or MOV that’s in the surge protectors. The MOV diverts the excess current into the power outlet’s grounding line to ensure the electronics and devices get a consistent power level.  

When the MOV detects high voltage levels, it siphons the excess energy to reduce electrical pressure. If the voltage dips, the MOV in a typical surge protector increases resistance. The MOV kicks in automatically to redirect the excess electricity while allowing the electrical devices and appliances to keep operating. 

Not all electrical devices need a surge protector. However, many big-ticket appliances and electronics in your home require protection from destructive power surges. Because not all surge protectors are created equal, you’ll have to look at several factors when you shop for one. Here are some of them 

Joule Ratings

A joule is a measure of energy that’s released over a period of time. One example is a lightning strike which discharges about 1 billion joules of energy over a fraction of a second. 

The joules rating of surge protectors tells you how much energy the equipment can absorb before it stops working. Surge protectors with higher joules ratings can provide surge protection better and longer than those with lower ratings. For example, a surge protector with a rating of 1,000 joules will last longer than one with a 500 joules rating. 

The joules rating you need will depend on the type of device requiring protection. For delicate electronics and high-ticket appliances, such as laptops or air conditioners, avoid surge protectors with joules ratings under 1,000. However, if you’re protecting less sensitive devices, such as a blender, a lower rating will suffice.  

Clamping Voltage

Clamping voltage is the level where the surge protector’s MOV begins siphoning off the excess voltage to the ground to reduce it to a manageable level. For example, a surge protector might suppress or limit a 6,000V surge to only 600V. A lower number indicates better protection. However, it also means a lower lifespan for the unit.  

A clamping voltage of 400V or greater is too high. Look for surge protectors offering around 330V or less. 

Response Time

Because the device is reacting to an electrical force, the surge protector doesn’t kick in immediately. There is a slight delay, measured in nanoseconds before it can respond to the excess electricity that comes through the power line.  

Response time refers to how long it takes for the surge protector to begin redirecting the transient voltage spike to the ground. The lower number indicating the response time, the better because a longer delay means your equipment will be exposed to the surge for a more significant period. 

Anything above one nanosecond is too long and won’t provide sufficient protection for sensitive components. Also, a surge suppressor with an indicator light works best for these components, as the light will tell you that the protector hasn’t failed.  

Surge Protector vs Power Strips

A surge protector and a power strip may look alike, which is why some people think they work the same way. Well, they both provide you with multiple outlets to plug in your devices and appliances. However, a power strip’s function ends there. It only allows you to expand your wall outlet by giving you more sockets for your electronics. Some power strips have a circuit breaker with an on-off switch. However, that won’t prevent most electrical issues. 

Meanwhile, a surge protector keeps sensitive components safe from the extra voltage coming through the electrical lines. These extra voltages or surges not only damage appliances and electronics but can lead to an electrical fire as well. 

Sometimes it’s hard to tell the difference between a surge protector and a power strip just by looking at them. You can check the packaging to figure out what you’re purchasing. If you see information about the joules rating, that indicates that the unit is a surge protector.  

Power Surge vs Power Spikes

Some people interchange the two, but a power surge and spike differ slightly from each other. When the increase in voltage lasts for only 1 to 2 nanoseconds, that’s a power spike. But when the rise in voltage continues for 3 seconds or more, it’s called a power surge.

The difference in duration may seem minimal, but the excessive current flowing way for even just a billionths of a second more can inflict severe damage on an appliance if the surge is way beyond normal levels. 

Common Causes of Power Surge

Power surges are common occurrences, and several reasons are behind these events. The most common cause of surges are the following: 

  • Electrical overload: Occurs when you draw too much power from a single circuit, such as when you plug an appliance that’s beyond the circuit’s amperage rating or plug too many devices into one circuit. By drawing more power than what the circuit can provide, you overload it, which, in turn, leads to electrical surges. 
  • Faulty wiring: Old and worn insulation can expose the wires. When the exposed wires make contact, they can drive up the current flowing through them. 
  • Power outage: It’s not the power outage per se that causes a surge, but rather it’s the possible jump in current when the power returns that trigger the spike in voltage. 
  • Lightning strike: A lightning strike disrupts the flow of electricity in an electrical system because of the massive amount of heat it creates. The heat can melt the components in the system, causing a surge in power and damaging all appliances and devices connected to your outlets. 
  • Events within the home: The voltage jump caused by an appliance kicking on can lead to spikes in electric current. These appliances include refrigerators and air conditioners, which have compressors or motors that draw a significant amount of electricity. When the motor or compressor switches on, the brief but high electricity demand disrupts the steady voltage flow. 
  • Utility Company’s equipment: Issues with the power lines, transformers, and other equipment can lead to electrical surges. 

Common Causes of Power Spike

Power spikes are similar to power surges, so most things that cause power surges can also be behind power spikes, which are actually smaller surges.  

Electronics & Appliances that Needs Surge Protection

A surge protector is one of the most affordable yet essential pieces of equipment you can buy. Don’t risk frying your devices and appliances by leaving them unprotected from excessive electricity. 

But what should you plug into your surge protector?  

Keep in mind that modern devices are more sensitive to fluctuations in power than older models as they employ the newest and most advanced technology. Also, those with microprocessors are prone to the damaging effects of surges. For example, the stress components experience during sudden shutdowns when the power goes off is the leading cause of hardware failures in computers and other electronics.   

As a general rule, use protection for expensive or irreplaceable appliances and electronics. These include: 

  • Video game systems 
  • Computers/laptops 
  • High-end audio equipment 
  • Televisions 
  • Modems/routers 
  • AC units 
  • Refrigerators 

Tips before Buying a Surge Protector

Most surge protectors will work most of the time. How much protection they offer depends on the size, type, and quality of the device. Also, note that no surge protector inside the house will protect against a nearby lightning strike. Protection against lightning and other serious surges requires a whole-house surge protector installed before your main electrical panel.

Don’t fret if you can’t afford to install a whole-house surge protector. Fortunately, power surges caused by lightning strikes are uncommon, so you can go for whole-house surge protection when your budget permits. In the meantime, here’s what to consider when you purchase a surge protector strip. 

  • What do you want to protect: High-priced appliances and electrical devices require protection. So the more expensive devices you have, the more you need a surge protector. 
  • The number of ports you need: How many appliances or devices do you have that require protection? The answer will tell you how many ports the surge protector should have. 
  • The UL seal: The UL (Underwriters Laboratories) seal ensures that the device is safe and meets the necessary standards. The device should meet the minimum 1,449 standards. 
  • The clamping voltage and energy absorption rating: The ratings will depend on the equipment you want to protect. Ideally, the unit’s clamping voltage should be 400 volts or less, while the energy absorption rating should be a minimum of 700 joules.  
  • Presence of an indicator light: The indicator light will tell you that the device is operating as it should and that your appliances are protected from sudden spikes in voltage. 
  •  Warranty: Some surge protectors come with a lifetime warranty. Read the fine print to determine what the warranty covers. 


What Not to Do with Surge Protectors?

To ensure that the surge protector protects your appliances from damaging power events and the risk of fires, avoid a daisy chain connection. This means plugging other surge protectors or power strips into another surge protector. In addition, make sure the electronics or appliances you plug in don’t exceed the surge protector’s wattage capacity. Doing so could overload the unit. An overloaded surge protector won’t prevent a power surge and can even start fires. 

What Triggers a Surge Protector?

The metal oxide varistor (MOV) in surge protectors draws off extra voltage to provide a consistent power level to the devices plugged into it. The MOV is like a pressure-sensitive valve that gets triggered when it detects high voltage levels. 

How Do I Know What Size Surge Protector I Need?

The joule rating of a surge protector indicates the amount of protection it can provide, and how much joule rating you need depends on the device you want to protect. The more expensive the equipment, the higher the joule rating you’ll want to get. Surge protectors rated for 1000 joules are optimal for protecting small kitchen appliances, digital clocks, and lamps. But if you want the best protection, opt for the highest joule rating available, 2000+ joules. Also, consider purchasing a model with the highest response time. One that responds in less than a nanosecond offers the optimum level of protection. 

Is Turning off a Surge Protector the Same as Unplugging?

Turning a surge protector off is not the same as unplugging it. When you turn the device off, you shut off the electricity supply to that outlet. However, when an appliance remains plugged into a socket, it continues drawing power whether it’s turned off or not. So, pulling the plug from the socket is a better option if you aim to save electricity. Doing so can lead to approximately 10% savings on electricity consumption. 


Surge protectors keep your electronics and electrical devices safe from damaging spikes in voltage. But to ensure you get the best protection, you’ll have to know how they work. Also, you’ll need to find the type, size, and model that suits your needs to get the most for your money. 

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