About Surge Protection Devices

It’s not something everyone knows about, but your home is under attack on a daily basis by an invisible threat. If you have any electronics in your home, and most people do – your LCD or plasma television, any media peripherals like DVD players or Xbox 360s, your computer, even your microwave – they are susceptible to the dangers of power surges. Any electronic device in your home can be damaged either slowly or instantly by an electrical surge.

It’s not only your electronics that stand being disabled, either. Your entire home wiring can be affected. From outlets to garage door openers, power surges can strike anything with an electrical current. These highly charged spikes in power flow can burn up the circuits of appliances and even cause old wiring to ignite. Fires from wiring issues are the number one cause of home fires across the country.

It seems alarming and makes your home sound vulnerable but there is a defense. Surge protection devices can stop surges and protect your home. While they have many names (voltage limiters, overvoltage protectors, surge arresters, surge suppressors, transient voltage surge suppressors (TVSS), or secondary surge arresters), the all have the same function. With that said, they can be broken down into two categories. The first is an electrical panel surge protector, installed at what is considered the service entrance portal where your power comes into the house, the breaker box. And the second, point-of-use surge protectors, which connects directly to an appliance or other electronic. The most common point-o-use device is the surge strip that plugs into your wall outlet.

What They Protect

While most residences aware of surge protection implement some sort of point-of-use device for their electronic equipment, and while that may be enough protection for most homes, many professionals recommend both types of devices to be installed.

Service Entrance Surge Protection

Whole house surge protection stops surges coming into your home on your power lines, phone lines, cable television lines and satellite dish systems. They are installed either at the meter side of your main panel or between your breaker panel and the incoming lines. In essence, they protect items that are hard wired into the house. Motors, lights, outlets, light switches are all examples of hard wired items. You can still guard each line separately with a single surge protector set up with the appropriate capabilities and other specifications (RJ11, RJ 45 phone and Ethernet lines, coaxial connections, and standard outlets), but the whole house surge protector will stop much larger surges.

A typical point-of-use (will refer to these as appliance surge protectors) device will have a clamping voltage of 330 volts. This is the point at which your surge protector realizes there is a surge and acts to stop it. The reason these are recommended along with a whole house device is that this low clamping voltage (330-volt is the best) will catch smaller interior surges that start within the home from things like air conditioners turning on and off.

An appliance surge protector can safeguard any electronic item that plugs into a wall outlet. This includes any item that starts with a push button: digital clocks, radios, stereos, televisions, computers, microwaves, etc.; anything with a digital display. It can also protect phone lines, cable lines, Ethernet connections, modems, etc.

While these surge protective devices can stop large surges, they are not capable in extreme cases. No surge protector can stop ALL surges. Lightning, as the best example, will overpower even the best surge protector, as its strength is just too much for a device to bear on a direct blast. That’s not to say that a whole house surge protector can’t lessen the influence of an indirect hit, however. It can. And that can reduce the effect further by the time the surge reaches your individually protected appliances.

How They Protect You

At the center of the surge protection device is its functioning mechanism, the MOV. MOV is an acronym for metal oxide varistor. It is a little semiconductor of various granular metals (zinc, bismuth, cobalt, manganese) coated in ceramic. The granules are arranged in such a way that they create a one-way flow of current in a diode. As there is only so much room in a surge protector, there can be only so many MOVs. The more and the larger they are, the greater the protection the device offers.

Metal Oxid Varistors (MOVs)

When a surge is detected, the MOVs attract the excess flow of electricity (called shunting) and redirects it to the grounding system until there is no longer a threat. In other words, it acts as a valve. It opens to let through the excess power to a safe area and closes when that excess returns to normal. This is called clamping voltage.

In the process of redirecting excessive current, the MOV heats up. The larger the surge the hotter the MOV gets as it works harder to move the energy away from your equipment. This causes it to degrade over time and means that your surge protector is more of a sacrificial device because eventually the MOVs will no longer function. However, you can get several good years out of a surge protector as the MOVs can withstand several hundred degrees before degradation sets in.

Tips For Purchasing Your Surge Protection Device

Service Entrance Surge Protection

These devices are manufactured in one of two kinds: a Transient Voltage Surge Suppressor (TVSS) or a secondary surge arrestor. TVSS devices are made for indoor use only and can include point-of-use devices. Secondary surge arrestors are made both indoor and outdoor use. While both are more than capable of protecting your home, they are not easily compared to each other as each has its own set of standards. TVSS devices fall under the Underwriters Laboratory (UL) 1449, 2nd edition. Secondary devices use the Institute of Electrical and Electronics Engineers (IEEE) C 62.11. These two organizations have their own sets of quality control to ensure each device they test meet their particular safety standards. Instead you can base your choice on individual specs.

Surge Protector Specifications:

• Fuse protection: A TVSS device will offer thermal fuse protection; SSA devices are already fused.
• Clamping voltage: This is the point at which your surge protector detects and stops surges. While there are no standards set for maximum protection, clamping voltage on most quality surge protective devices ranges from 330 volts to 800 volts with 330V being the best. Clamping voltage is a UL standard of testing.
• Line Protection. The best TVSS units will have protection for all lines. These are line-to-neutral (L-N), line-to-ground (L-G) and neutral-to-ground (N-G). SSAs, since there are installed only on the utility side of your panel, use L-N protection.
• Coax and RJ11/RJ45 Protection: Either designed as part of an outlet surge protector or as individual devices, all phone lines and cable lines should be protected.
• Indicator Light(s): Most devices today have alert systems to let you know the device is functioning as it should. This is important because your device will still act as a conduit for electricity even if it isn’t protecting you.
• Joules rating: This number determines how much of a surge your device can handle at once. Obviously the higher the number the more protection is offered. The Joules rating is found on the package of the device.
• Warranty: All quality products will have an endorsement by the manufacturer in the form of a warranty. Most of the time a TVSS warranty covers connected equipment that has been damaged as a result of a faulty device. This is called a Connected Equipment Warranty (CEW).

Point-of-Use Surge Protection

Again these fall under the subcategory of TVSS, meaning they should all carry the UL 1449, 2nd edition or UL 1449 3rd edition standard.

Surge Protector Specifications:

• Thermal Fuse Protection: This should be a standard to look for. It protects devices up to a predetermined temperature reducing the risk of electrical fires caused by power surges.
• Clamping Voltage: Again, 330Volts is the best rated clamping voltage for a TVSS UL 1449 device. Look for the lowest possible CV you can find. It will be listed on the device’s rating plate.
• 3 Line Protection: L-N, L-G, N-G. (see above for details.)
• Media Protection: Phone and coax protection should be included in devices used to protect VCRs, DVD players, Stereo systems and home theater systems.
• Power Flow Control: It is important to find a device that stops the flow of electricity when it reaches its critical mass of protection and stops working.
• Indicator Light: Either power, ground or both indicator lights are suggested. Ground wire indicator lights will let you know if your device is properly grounded and working as it should.
• Joules Rating: The higher the better. Though Joules ratings have not been standardized, 300 Joules is the minimum suggested for small appliances.
• CEW: Connected Eequipment Warranty.

It is important that you do not use extension cords or even another surge protector to daisy chain devices. The protection offered by one device will be diminished or negated. Warranties will not cover this kind of loss.

How Much Does Surge Protection Cost?

In regards to service entrance protection, it is advised to have a professional installation to ensure proper connection. You may also have to get permission from your utility company to have this done as many companies provide street side protection as part of their equipment, either as a standard or for a small fee. Some service entrance devices (between panel and home lines) are manufactured as snap-on devices that can easily be installed yourself.

Depending on the company, installation costs will vary. Costs of the actual surge protection device can range from $30 to more than a couple hundred dollars. Check the reputation of the manufacturer before you make your purchase as price does not always determine quality.

Because there are so many variations for different appliances, point-of-use devices can cost anywhere from $5 to over a hundred dollars.

Why Has Surge Protection Become So Important Recently?

Power surges have existed since the standardization of electricity in homes in the 19th century. Why they have become so prevalent today is because of advances in technology creating smaller and more sensitive electronic circuitry. Circuits are more centrally located to one another creating a greater susceptibility to surges. Networking of equipment also creates vulnerability. Phone lines, cable lines, all electrical conduits make surges more likely, which in turn makes damage more likely. Knowing which surge protection devices you need to protect yourself, your home and your electronic equipment is becoming more and more important with each advance we make.

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