Surge Protectors

Why use it?

Components in today's electronic devices (including everything from computers and entertainment systems to home appliances like microwave ovens) are smaller and more delicate than their predecessors, and thus more sensitive to fluctuations in current. Microprocessors, in particular, require stable current at the right voltage -- a nice, steady flow of 240V mains power. Unfortunately, electrical power quality changes frequently, even hourly. Anything over the standard voltage is called a "transient" and, depending on its severity and duration, can also be called a "spike" or "surge". Even though they may be so brief that they are measured in nanoseconds (billionths of a second), they can still damage your equipment. A surge lasts three nanoseconds or more; a spike only lasts 1-2 nanoseconds but both can cause damage. Surges, spikes and sags occur daily. Many are virtually unnoticeable, but inevitably, some stronger power pulses will cause damage -- either immediately or over a period of time. The time before and after an outage (blackout), especially during a thunderstorm, is characterised by noticeable surges and sags, much like how tremors are felt before and after an earthquake. Even if you do not personally notice these fluctuations, your unprotected electronic equipment will.

How surge protection works

A surge protector usually works by channelling any extra voltage into the electrical outlet's "earth" or "ground" wire, thus stopping it from reaching your equipment. At the same time, it still allows the normal voltage to continue. In the most common type of surge protector, the extra voltage is diverted by a component called a metal oxide varistor, or MOV. A MOV provides strong surge protection, but degrades each time. It may even last only once. Another common (and cheaper) type of surge protection is provided by a gas discharge arrestor (gas tube). It uses an inert gas which only becomes conductive under a strong surge of electricity, then diverts the excess harmlessly to "ground". Silicon Avalanche Diodes (SADs) are known for their fast response time and low voltage clamping level. Clamping voltage is the maximum amount of voltage that a surge protector will let through before it suppresses the surge by conducting electricity to the ground line. The lower the clamping voltage the better the protection. A plus for SADs is that unlike MOVs, they don't degrade with repeated surges so they last longer. But MOVs provide better strong-surge protection. The best -- but naturally, more expensive -- surge protectors include a combination of SADs and MOVs and possibly gas tubes as well.

Blow a fuse, not your equipment

Some models also have a fuse within the surge protector. When a surge occurs, the protector routes the increased voltage to the grounding wire, but if the voltage is too great, it will blow the fuse. The unit can be re-used when the fuse is replaced. Happily, so too can your equipment. While computers typically come with some measure of surge protection built into the power supply unit (PSU), this is nowhere near as robust as a dedicated surge protection device, which may also include line conditioning and data line protection, along with surge protection for several devices. TIP: A power filter device can be, and should be, used for more than just protecting your computer. To be safe from harm, ALL electronic equipment around the home or office should be connected to mains power via a power filter, as all this equipment is sensitive to power fluctuations and can be damaged.

Insidious spikes and sags

It is important to note that not all damage to electronic equipment is caused by a massive electrical surge. Most often, power-related equipment failure is due to the "wearing down" of your components over months or years of exposure to relatively mild electrical spikes until, eventually, they burn out. Sags, also known as brownouts, also cause long-term damage. These are momentary drops in voltage often shown by dimming or flickering lighting. Like spikes, they are very common and can cause hardware crashes and even damage. On a computer, they can also create instability such as computer "freezes" or unexpected reboots, lost settings or even data corruption.

Line noise

Some surge protectors have a line-conditioning system for filtering out "line noise" (smaller fluctuations in electrical current). Noise can be generated by equipment on the same power circuit or by nearby devices, such as heavy machinery, motors, compressors, radio transmitters etc. Like spikes and sags, noise can cause intermittent and hard-to-trace problems with equipment, and eventually cause equipment failure.

Join the Good Gear Guide newsletter!

Error: Please check your email address.

Our Back to Business guide highlights the best products for you to boost your productivity at home, on the road, at the office, or in the classroom.

Keep up with the latest tech news, reviews and previews by subscribing to the Good Gear Guide newsletter.

GoodGearGuide Staff

Good Gear Guide
Show Comments

Essentials

Lexar® JumpDrive® S57 USB 3.0 flash drive

Learn more >

Microsoft L5V-00027 Sculpt Ergonomic Keyboard Desktop

Learn more >

Mobile

Lexar® JumpDrive® S45 USB 3.0 flash drive 

Learn more >

Exec

Lexar® Professional 1800x microSDHC™/microSDXC™ UHS-II cards 

Learn more >

Lexar® JumpDrive® C20c USB Type-C flash drive 

Learn more >

HD Pan/Tilt Wi-Fi Camera with Night Vision NC450

Learn more >

Audio-Technica ATH-ANC70 Noise Cancelling Headphones

Learn more >

Budget

Back To Business Guide

Click for more ›

Most Popular Reviews

Latest News Articles

Resources

PCW Evaluation Team

Azadeh Williams

HP OfficeJet Pro 8730

A smarter way to print for busy small business owners, combining speedy printing with scanning and copying, making it easier to produce high quality documents and images at a touch of a button.

Andrew Grant

HP OfficeJet Pro 8730

I've had a multifunction printer in the office going on 10 years now. It was a neat bit of kit back in the day -- print, copy, scan, fax -- when printing over WiFi felt a bit like magic. It’s seen better days though and an upgrade’s well overdue. This HP OfficeJet Pro 8730 looks like it ticks all the same boxes: print, copy, scan, and fax. (Really? Does anyone fax anything any more? I guess it's good to know the facility’s there, just in case.) Printing over WiFi is more-or- less standard these days.

Ed Dawson

HP OfficeJet Pro 8730

As a freelance writer who is always on the go, I like my technology to be both efficient and effective so I can do my job well. The HP OfficeJet Pro 8730 Inkjet Printer ticks all the boxes in terms of form factor, performance and user interface.

Michael Hargreaves

Windows 10 for Business / Dell XPS 13

I’d happily recommend this touchscreen laptop and Windows 10 as a great way to get serious work done at a desk or on the road.

Aysha Strobbe

Windows 10 / HP Spectre x360

Ultimately, I think the Windows 10 environment is excellent for me as it caters for so many different uses. The inclusion of the Xbox app is also great for when you need some downtime too!

Mark Escubio

Windows 10 / Lenovo Yoga 910

For me, the Xbox Play Anywhere is a great new feature as it allows you to play your current Xbox games with higher resolutions and better graphics without forking out extra cash for another copy. Although available titles are still scarce, but I’m sure it will grow in time.

Featured Content

Latest Jobs

Don’t have an account? Sign up here

Don't have an account? Sign up now

Forgot password?