The Guide to Surge Protectors (Page 2)

By: Jonathan Z. Kremer

How can you protect yourself?

Your electrical equipment can be protected by using a surge protector or UPS (To learn more about UPSs see "Do You Need A UPS?"). A surge protector (also called a surge suppressor, surge arrestor, transient voltage surge suppressors (TVSS), secondary surge arresters, or surge strip) is a device which is specially designed to absorb any voltage spikes or surges. This prevents the voltage fluctuation from being passed on to delicate electronic circuitry. Some filter out the electromagnetic interference (EMI) and radio frequency interference (RFI) too.

There are basically two types of surge protectors.

Service entrance surge protectors - These are hard wired to the service panel (main electrical panel) where your circuit breakers are located, or next to your electric meter. These devices are designed to stop harmful surges before they can travel towards the electronic equipment in your home.

Point-of-use surge protector - These devices are used near the appliance that is being protected. It includes the type of surge protectors that plug into a wall outlet.

Surge protectors are rated for different purposes and uses, which fall under two categories:

Transient Voltage Surge Suppressor (TVSS): TVSSs are rated and designed to be used after the main disconnect (main breaker or switch) in the service panel. In the US, they are tested according to Underwriters Laboratory standard (UL 1449). UL 1449 assigns a clamping voltage to the TVSS which can be used for comparison from one product to the next. The clamping voltage is the maximum amount of voltage that a surge protector will allow through itself before it will suppress the power surge.

These devices include the point-of-use surge protectors and service entrance surge protectors mounted on the electrical panel (after the main disconnect).

Secondary Surge Arrester: These devices are tested and rated for use before the primary disconnect to a facility (the main electrical panel). Unlike TVSS type protectors, secondary surge arresters can be connected both before or after the main-disconnect. In the US they are rated by the recommendations of the Institute of Electrical and Electronics Engineers (IEEE) standard C62.11. A clamping voltage is not assigned by the IEEE (C62.11) for secondary surge arresters, making it difficult to compare the capabilities of the different type surge protectors.

Secondary surge arresters include both the meter-mount surge protectors and the plug-on surge protectors that snap into the electrical panel.

Important note #1:

On some surge protectors you will see the term "Let Through Voltage". The "let through voltage" is the voltage that passes through the surge protector to your devices. Although the "let through voltage", is similar to the clamping voltage, they are not the same.

The clamping voltage will be equal to the "let through voltage" only if the power surge is exactly the size, shape and duration of the 6,000-volt surge required in the UL 1449 test standard. If the surge is higher, the "let through voltage" will most likely be higher too.

When protecting your home it's important to remember that a service entrance suppressor can't stop surges sufficiently by itself. Up to 15% of excess voltage may leak by. That's where "point-of-use" surge protectors come into play. They act as an additional buffer between individual appliances and wall outlets.

Surprisingly, there is a lot of controversy surrounding surge protector technology, causing flaming debates across the Web. Electronic experts are somewhat divided over the best way to deal with power surges, causing a situation where each manufacturer claims that their technology is inherently the best. One thing is for certain, no surge protector is 100% effective. Not only is it possible that a top of the line piece of equipment can have serious problems or defects, but those unlucky enough to experience a violent burst of voltage from a direct or very close hit of lightning, will probably find their surge protector fried and their appliances damaged never-the-less. A very close or direct hit of lightning is simply too much for your average surge protector (or UPS) to deal with. If your surge protector is in the way of the lightning's path, all or part of the lightning will just flash over or through the device - regardless of the number of capacitors and battery banks incorporated. Of course this does not mean that you should not use a surge protector (or UPS). Using top quality surge protectors will give you a very high percentage of protection from everyday power line spikes and distant lightning strikes. But when lightning hits directly or nearby, all bets are off.

Tip:

When a lighting storm is near, the best way to protect your appliances from a lightning strike is to unplug them from the outlets, together with your surge protectors and UPSs. A lightning bolt, that can melt holes in steel and jump through kilometers of empty air, isn't going to even notice the "surge protection" electronics in a power strip or UPS and it isn't going to be stopped by the tiny air gap inside an on/off switch. Don't forget to unplug telephone, cable, and antenna connections too.

Important Note #2:

A GOOD GROUNDING IS CRUCIAL for surge protectors and UPSs to work. Most Surge-Protection Devices or (SPDs for short) are composed of Metal Oxide Varistors (MOVs). These small MOVs are designed to "turn on" or activate at a given voltage level. When it detects voltages over a certain amount, it immediately diverts the surge to the ground. Therefore surge protectors must be plugged into three prong outlets and the grounding system must be in working order. If there are any grounding problems, a competent electrician should be brought in to make the necessary repairs and/or changes.

Many surge protectors have a ground indicator light which will show if your outlet is properly grounded or not.

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