Do You Really Need a Surge Protector?

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Back when I didn’t know any better, I thought “surge protector” was synonymous with “power strip,” and I thought “power strip” was just a fancy multi-plug extension cord. Learn from my mistakes: they are not the same things! A surge protector is more than just an apparatus for turning one outlet into six – it plays an important role in electronic device maintenance, such as protecting your laptop.

Why are surge protectors important? Do you need a surge protector? If so, how do you go about selecting one that works for you without blowing huge wads of cash? Keep reading to find out.

How Surge Protectors Work

Before we can define how a surge protector works, we need to define an electrical surge. Think of the flow of electricity as the flow of water running through a pipe. Water moves from one end of a pipe to the other end due to water pressure – water moves from high pressure to low pressure. Electricity operates in a similar way, moving from areas of high electric potential energy to areas of low electric potential energy. In this case, it’s from one end of a wire to the other end.


Voltage is a measure of this electric potential energy – more specifically, the difference in electric potential energy. When the voltage increases above the norm for at least 3 nanoseconds, it’s called a surge. If the surge is high enough, it can cause wear and tear on your electronic devices, or in severe cases even destroy them.

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Let’s go back to the water pipe example. If the water pressure within the pipe is too great, the pipe will burst. The same thing is true for electrical wiring. If the voltage of the wire is too great – meaning the difference in electric potential energy from one end to the other is too high – then the electricity will surge through. This heats up the wire, and if hot enough it can burn, rendering it useless.

The surge protector, then, has one job: detect excess voltage and divert the extra electricity into the grounding wire. This is why all surge protectors will have a grounding pin (the third prong on a plug) and all surge protectors must be plugged into a properly grounded outlet for them to work as intended.

When to Use A Surge Protector

So what causes an electrical surge? Most people think that the main culprit of electrical surging is lightning, but that’s not true at all. Yes, lightning can and does cause electrical surges, but the voltage of lightning is so great that most surge protectors won’t be able to withstand their power. During a lightning storm, the only way to be absolutely sure that your devices won’t be surged is to unplug them.


The main culprit of electrical surges? Electrical devices that require lots of power to operate. Depending on the wiring of your home, you may notice at times that your lights flicker when powerful devices turn on and off, e.g. your air conditioner. When these devices are switched on, they demand a lot of electricity, which puts a lot of strain on the grid and can cause surges.

When should you use a surge protector? All the time. The real question is really which devices you should connect to a surge protector. You don’t need a surge protector for your desk lamp or your standing fan, but you do want a surge protector for expensive devices that have intricate microprocessors, like computers, televisions, stereo systems, media centers, high-tech kitchen appliances, etc.

Think of it this way: if there was an electrical surge that destroyed all of the devices connected to your outlets, which lost devices would pain you the most? Plug those into a surge protector. It’s better to be safe than sorry.

On an offbeat note, surge protectors can be useful for reducing cable clutter and improving organization with your electronics. All of the cables end up being directed to the same destination, making it much easier for you to handle them all neatly.

Choosing the Right Surge Protector

It can be difficult finding the right surge protector for your needs at a good value, mostly because people don’t talk about it very often. What makes a surge protector good? And why are some surge protectors much more expensive than others? Are there any features you should be looking out for?


The first thing you’ll want is an indicator light. Do not compromise on this. Surge protectors will not last forever – in fact, even when the surge protector properly diverts a surge so your electronics aren’t damaged, the protector itself can be damaged in the process. An indicator light will let you know that your surge protector is working fine. Is the indicator light not working? Time to buy a new surge protector.

As for protection power, good surge protectors will come with a UL rating, a rating put out by the independent Underwriters Laboratories that tests the safety of electronic devices. Don’t bother with a surge protector that doesn’t have a UL rating. Also make sure that the product is a “transient voltage surge suppressor” as many UL-rated power strips still might not offer surge protection.

And there are a few other considerations to make:

  • Clamping voltage is the voltage measurement that prompts the surge protector to start redirecting the excess electricity away from the plugged-in devices. In other words, a surge protector will a lower clamping voltage will trigger earlier, thus better protecting your devices. Any surge protector with a clamping voltage below 400 volts should be good enough for home use.
  • Joule rating is the maximum amount of energy the surge protector can absorb. If the surge breaches this maximum, the surge protector will be rendered useless. The higher the joule rating, the more energy can be absorbed by the surge protector, so a higher joule rating will often indicate a longer lifespan for the product. For best household protection, you’ll want a surge protector with a joule rating of at least 600.
  • Response time is how long it takes for the surge protector to detect a surge in electricity. A lower response time means a faster response time, which reduces the time that your plugged-in devices are exposed to the surge, thus protecting them better. Ideally, you’ll want a surge protector with a response time of 1 nanosecond or faster.

Recommended Surge Protectors

If you need some help getting started with finding a good surge protector, here are some that I recommend. All of these have a UL rating of 1449, which is what you should be looking for:

  • Maruson SUG-B706NT ($20): A strong 7-outlet surge protector with indicator lights, a clamping voltage of 330V, a joule rating of 720, and a response time below 1 nanosecond. Perfect for an everyday household.
  • Tripp Lite TLP606 ($10): Another strong surge protector with 6 outlets, an indicator light, a clamping voltage of 150V, a joule rating of 790, and a response time below 1 nanosecond.
  • Tripp Lite SPIKECUBE ($6): Here’s an interesting surge protector with only 1 outlet. It has two indicator lights – one for grounded, one for protected. It has a clamping voltage of 150V, a joule rating of 600, and a response time below 1 nanosecond.


The take away? All electrical grids experience electrical surges, some more than others. These surges can damage electronics and surge protectors are there to keep those surges under control as much as possible. You’ll want to use surge protectors for complex and valuable electronics, such as computers, appliances, and media centers. Keep in mind that it’s not enough to have a surge protector; you need one that’s properly rated for your needs.

Do you use surge protectors? If not, why not? Have any interesting electrical surge stories to tell? Please share your thoughts with us in the comments!

Image Credits: Holiday fire safety Via Flickr, Electrical Grid Via Shutterstock, Air Conditioner Via Shutterstock, Surge Protector 2 Via Shutterstock

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Matt Smith

A friend of mine recently lost a television, a stove and a few other items to a power surge. The surge was so powerful a power meter at a house near to him blew up. I don’t know if the cause was ever determined; it happened on a sunny day with little wind and no reported accidents.

The story had a happy ending, though, because home owner’s insurance covers this sort of thing.

Joel Lee

Blown up power meter? Holy crap! That’s pretty weird, especially since it was on a sunny day without accident. Not sure if a surge protector would’ve protected against that, but good to hear that insurance covers it!

Lisa O

That sounds like something out of urban legend, the kind would like to see. He’s a lucky guy, your friend. Imagine if he didn’t have that kind of insurance.


Serra Stone

As seen in this picture, yes you do need a surge protector! If I wouldn’t have had one, a huge amount of money in computer parts would have been fried!



The way most surge protectors are linked internally, the surge will fry the outlet closest to the power cord first. The second outlet provides a little more protection because the surge has to go through two levels of protection. Expensive or more sensitive devices should be furthest from the surge protector power cord. Theres no reason not to use one if you value your electronics.

Joel Lee

I never knew that about the “frying the closest outlet first.” It was always something that I thought might be true, but to hear someone else verbalize it and confirm it is quite interesting. I have a few surge protectors that I need to rearrange now!

Serra Stone

I also didn’t know that! But as seen in my pic above your post, it looks to be true. It fried the outlet closest to the power cord!



This may sound a little dumb, but are surge protectors the same as regular power strips? By power strips I mean the white bars that have multiple outlets with an on/off switch on one end.
It seems like a surge protector would need more room, so I’m assuming regular power strips just connect multiple outlets together to make more outlets than is available in the wall, and thus wouldn’t provide any more protection than just plugging it into the wall. Is this right?

Achraf A

Unfortunately, yes. Those “white bar” power strips just link up a few more outlets in parallel to the main power cord. In Contrast, a surge protector has actual circuitry to let it fire-up the protection if a surge is detected, in less than 1 nanosecond, lower than what it takes a voltage change to become a surge, which is 3 nanoseconds.


Mike C

This is why I have a power conditioner. Long live Furman.


Eric B

We lost some electronic equipment that was on a surge protector that was supposed to be good. The only equipment that survived was what was plugged into a philips SPP7345WA Turned out we had a bad “negative?” I think it was. Caused the whole house to surge off and on. I wish I could still find these. They are the best surge protectors we’ve ever had.



The best protection against electrical surges are UPCs. Those devices are powerful or smart enough to protect electronics from lightening. Top of the line UPCs generate graphs of electrical surges and then use algorithms to disconnect from the grid when surges peak.
A good UPC is expensive so the cheap alternative is to daisy chain surge protectors. The more surge protectors you have connected, the more protection you have (not to mention outlets)! I personally connect at least two surge protectors together for every device.

Achraf A

If you use more than 3500 W from a single outlet connected to multiple surge protectors, you are in real danger.

Shane E

I could be wrong, but you may want to do a little research on that. I’ve always read that daisy chaining surge protectors was a no no because it gives them a less direct path to ground.

Joel Lee

I have no idea what the right answer is here, but this one sounds the most reasonable to me. Time to do some research.


David Payne aka The Computer Guy

nothing can protect you from a direct hit of Lightning and with that said surge proctors and save you ALOT of money. But, if it is storming hard unplug or you may have to end up buying new equipment. The most common thing that people forget to unplug, on their computer is the Lan cable.


Exactly, must unplug electronic devices and specially, Lan Cable while lightning and storms. I learnt a lesson from of this painful experience in the past just couple of months ago. :)

Joel Lee

Yes, lightning is just too powerful. It might be an inconvenience to unplug everything whenever it storms, but that’s the best way to protect your electronics!



Great Info, thank you. However, this info would be useful 6 months ago…Had 2 computers condemned by lightning strikes last year and bought a Belkin . Happened to be the only brand available in the market and costs 3 times the price of the Maruson. Has 6 outlets. Imported from USA.
More brands are available now from Korea, Taiwan, Singapore. Belkin does give a guarantee and claims up to 20k USD for this model. How about the ones listed here?


Steve Conant

I guess I am surprised that anyone is having (not protected against) electrical events with their electronics. More surprised that this got to me through makeuseof. What is next week… backing up 3.5″ disks?

Shane E

Glad you know everything. This article was useful for me. I didn’t know what clamping voltage was, etc. Also, a lot of people know to put a surge protector in front of the PC or TV, but as this article points out kitchen appliances often need them too. I opened my new fridge one morning to be greated by a bunch of flashing lights on the control panel. The service tech told me to put it on a surge protector and it likely wouldn’t happen again.

Joel Lee

Agreed. There’s a difference between knowing THAT you should use a surge protector and knowing WHY you should use a surge protector and HOW to choose a good one. A lot of people don’t even know the difference between an outlet strip and a surge protector, so I wouldn’t call this stuff common knowledge.


Leland W

If you want better protection but no battery backup I would go one better and get an AVR (automatic voltage regulator) which has capacitors in it to even out the power whether there is a sag or surge in power. The sags are the thing that tend to kill high end electronics like computers. Surges of course too especially with lighting. However for a computer a good UPS with AVR is the best choice.

David Payne aka The Computer Guy

AVR’S are good for spikes and blackouts from the electric company, which happens alot down here in Florida, The Lighting Capital of the world, But nothing, absolutely nothing can block or stop a direct hit from lightening on your computer. I love bad weather, every time it rains, I make money. The sad thing is it is so simple to prevent. Unplug or pay.

Lisa O

Indonesian cities, like Pekanbaru, can compete with Florida for blackouts rate. It can happen even in the sunniest of days. Much better lately, tho.



The recommended surge protectors are rated 600…790 Joule. Can it be true???
Such cheap surge protectors are based on a disk varistor. In the best case, I mean a varistor 20 mm diameter, the maximum Joule are 100…200 Joule.
How can those surge protectors be rated 600…790 Joule?


Michael F

Why does nobody speak of Noise Filters on surge protectors anymore? I see it mentioned occasionally in the specs, but it’s a lot harder to spot than back in the late 90s when I used to sell them regularly in retail.

Line Noise occurs when other devices on your electric wiring generate, well, noise. The best example is an old analog television when you’d run the vacuum cleaner and suddenly there’d be static or lines and stuff. The noise filter in a surge protector would filter that out and protect your device from that interference.

Joel Lee

It might be because analog is a thing of the past and everything is moving towards (or has already moved towards) digital. I don’t think noise really interferes with digital, but I could be wrong.



Don’t just protect your mains connection, surges can also arrive via the telephone line. When buying a surge protector or a UPS, look for one that will protect your incoming telephone signal(s) as well.

Joel Lee

Good point. Not only the telephone line but also the ethernet cord!


Geoffrey Richardson

Maybe I have been lucky, but I have used surge protectors for at least 20 years and have survived lightning storms, power surges and sudden blackouts due to fallen branches across lines and strikes on sub-stations without losing any equipment.
Having no special knowledge of their workings, this article was of great interest to me. Thanks, Joel.

Joel Lee

It’s great that you went 20 years without a problem. Hope you didn’t just jinx yourself, ha!


Meidimi S

i once had to replace my mother board because a lighting storm fried it up. i don’t think a surge protector would have helped but i find them useful

Lisa O

My UPS was fried the week we needed it the most. A week of very frequent blackouts and my mainboard was fried, along with other small things. No joke indeed. Surge protector will replace power strips after this.


Paul V

Great article, I’m buying a couple Tripp Lite TLP606 next week.


Ole Tange

Neither I nor any of my friends use surge protectors and have never lost any device due to surges.

Could this be due to the fact that we have excellent wiring (e.g. the light never flickers if we turn on power demanding devices) and an electricity company that has an electricity drop out at most 1 time every 5 years?

Can you elaborate a bit more on what causes the surges? Is there a way to measure how many surges you have?

Joel Lee

The excellent wiring might have something to do with it. Surges don’t have to be big flashy events, though. Small surges that happen every once in a while can gradually deteriorate the quality and condition of your electronic devices.

I’m not really qualified to elaborate on the causes or measurements involved with surges, but maybe MUO Answers can help!



If you were to loose the neutral on your house and have a potential of 240 volts to an outlet would 240 volts smoke a computer? Yes , so how does the computer that is plugged into a surge protector with a clamp of 300 volts get saved? Im confused.



I am sorry to butt in but I am looking for an outlet extension that has outlets on the sides, for behind my TV. A lot like the Side Socket you see advertised.
It is called a surge protector, but is it any good? Is it possible to get a surge protector that has outlets on the sides like this?
I want to plug in my TV, Nintendo Wii, internet modem and internet router. Also my DVD player but it is only used rarely. Is a surge protector even necessary?
Thank you in advance for any advice.



I recently found out that you can buy whole-house surge protectors. In the UK I found one for £46 and it fits easily into a spare slot on the mains consumer unit (main fuse board)

That means you whole house is protected – every single circuit – lighting, sockets etc for not much more cost that a good quality six-outlet surge protected power strip. And, unlike most surge protected power strips, you don’t throw it away if a power surge occurs, you just have to reset it!

Most people probably plug their laptop into one of many sockets around the house and with a whole house surge protector all those sockets are protected too – as well as lighting and any other circuits.

You can also get whole house surge protectors that protect against lightning strikes too but I read you only need this (type 1) surge protector if you have overhead power cables feeding the house and/or you have a lightning rod fitted to your house. As I have neither, I will be going for a type 2/3 device.

Similarly, if you have overhead telephone lines feeding your property these need to be protected against lightning as well as they can destroy any equipment connected to them.

UPS (Uninterruptible Power Supplies) may also protect against power surges and the one I am thinking of getting, even offers a guarantee against lightning strikes and can also be reset after a power surge:

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