INFORMATION ABOUT SURGE PROTECTORS
Most modern businesses and homes are supplied with 120/240 volt power systems.
The normal voltage flow for 120 voltage will often range from 110-117 volts.
Computers, printer, stereo
equipment and TV sets have internal circuits sensitive to voltage fluctuations
and are often protected by surge protectors. Heavy draw appliances such as air conditioners, dryers, and electric stoves
generally have no need to be protected by surge protectors.
Surge Protectors are designed to trap the voltage that exceeds those limits. Excessive voltage
occurs due to power spikes. When these spikes occur for a sufficient duration, this activates the trapping device, a Metal Oxide Varistor
(MOV), located in the surge protector.
The MOV is the heart of surge suppressors. The role of the MOV is to divert surge current. However, MOVs wear out with
use. As more surges are diverted, the MOVs life span shortens, and failure
There is no forewarning or visual indications given - just failure. And while failing, they can reach very high temperatures, and
actually start fires.
Most surge protectors will continue to function as a power strip, even
though the surge trap mechanism may have been destroyed by the power spike.
This presents two possible dangers:
1) If another power surge should occur, it can damage the equipment or appliances that are plugged into this surge
2) If sufficient voltage passes through the surge protector due to a second power spike, a resistant short may have been formed,
allowing heating to occur and a fire to ignite.
When buying this equipment, look for a surge protector with an indicator
light that tells you if the protection components are functioning. All MOVs
will burn out after repeated power surges. Without an indicator light, you
have no way of knowing if your protector is still functioning properly. Unfortunately due to manufacturing differences, the light may be "on" or
"off" during proper operation. It is important to review the operating instructions provided with the surge protector.
Every year, thousands of fires result from surge protectors, power strips
and electrical cords. Listed below are some suggestions to help prevent a
possible fire from igniting.
USE ONLY SURGE PROTECTORS OR POWER STRIPS THAT HAVE AN INTERNAL
These units will trip the breaker if the power strip is over loaded or
shorted to prevent overheating and fire.
All surge protectors or power strips need to be UL approved. Be sure that
the product is listed as a TRANSIENT VOLTAGE SURGE SUPPRESSOR. This means that it meets the criteria for UL 1449, UL's minimum performance
standard for surge suppressors. There are a lot of power strips listed by UL
that have no surge protection components at all. They are listed only for
their performance as extension cords. On a UL listed surge protectors, you
will find a couple of ratings. Look for:
* Clamping voltage. This tells you what voltage will cause the MOVs
to conduct electricity to the ground line. A lower clamping voltage indicates better protection. There are three levels of protection in the UL
rating-- 330 V, 400 V and 500 V. Generally, a clamping voltage more than 400 V is
* Energy absorption/dissipation. This rating, given in joules,
tells you how much energy the surge protector can absorb before it fails. A
higher number indicates greater protection. Look for a protector that is at
least rated at 200 to 400 joules. For better protection, look for a rating
of 600 joules or more.
* Response time. Surge protectors don't kick in immediately; there
is a very slight delay as they respond to the power surge. A longer response
time tells you that your computer (or other equipment) will be exposed to
the surge for a greater amount of time. Look for a surge protector that responds in less than one nanosecond.
Visually inspect all surge protectors or power strips on a regular basis to
ensure that they are not damaged or showing signs of wear or damage. During
the visual inspection, ensure that the plug is fully engaged in their respective outlets. The surge protector or power strips should always have
either a polarized plug with one of the blades being larger then the other
one or a three-prong grounded plug. Never use a three to two prong adapter
to power the unit. Surge protectors or power strips should have a cord of no
more than 6 feet in length. When the surge protector or plug strip is not in
use, unplug the cord from the power source.
More information on