Choosing a Surge Suppressor
By Michael Seaforth
people protect their computer with a surge suppressor. So, how should
someone go about choosing one? Should you just buy the most expensive
one in the store? Should you assume that the $30 unit is better
than the $20 one? Ultimately, there is a limit to what each of us
is willing to spend on protection. By looking carefully at the specifications
on the package, we can put ourselves in a better position to make
a wise choice.
are used to provide some measure of protection from sudden increases
in voltage and current that could damage a computer or other electronic
device. We therefore want the suppressor to operate quickly, be
able to handle a lot of energy without being destroyed and keep
both the voltage and current in check.
factors contribute to the severity of the surge that might occur
at a computer. The design of the power system in the area you live
and the likelihood of lightning storms are beyond your control.
However, within the building, you can select the level of protection
the typical home user where the only protection available is the
suppressor at the computer and where cost is an important determining
factor, paying attention to certain key specifications (often
in very small print)
will increase the bang for the buck. A suppressor that is also equipped
with modem and fax protection will offer even greater protection
since surges can enter the home through the telephone line. The
values shown below pertain to the power section of 120 V surge suppressors
Time: This should be less than 1 ns (nanosecond).
Voltage: This should not be greater than 330 V
Surge Energy/Dissipation: This will determine whether your suppressor
survives or gives up the ghost. Pay close attention to this when
comparing suppressors. The higher the value, the better. The value
is expressed in Joules (J) and may vary from about 270 to 1200J
or more for your typical suppressor. In severe cases a suppressor
may become permanently damaged and have to be replaced after handling
a powerful surge.
Filtering: This is sometimes just shown as attenuation and is
expressed in decibels (db). This is a measure of how well it will
protect your system from power line disturbances that can cause
your computer to freeze up or data on your hard drive to become
corrupted. A higher number is better. Typical values range from
15 to 40 db for your home suppressor. However, unless the values
shown are at the same frequency, a proper comparison cannot be made.
Surge/Spike Current: This is a measure of the ability of the
unit to handle current surges without being destroyed. Usually shown
in kiloamps (kA), a larger number is better.
and most importantly, you should ensure that the device is approved
to the safety standards for the country you live in. Many people
neglect to do this and may be putting themselves at risk. Typical
markings to look for are the UL marking in the US and the CSA, cUL
or other marking in Canada. Users outside of North America should
enquire about the approval required for their country.
now that you have purchased and installed your suppressor, is your
computer safe from harm? Well, it is never totally safe but there
is only so much you can do without spending an arm and a leg.
Always make sure that the ground terminal on the plug is intact
and connected at the power bar or suppressor. You should also verify
that the ground terminal is also connected at the wall and that
all receptacles are properly grounded. For this, you will need the
help of a qualified electrician or you could purchase an inexpensive
circuit tester at a hardware or electronics store. The purpose of
the third terminal is to protect the user from electrical shock
and to enable the suppressor to perform its intended function correctly.
you've been chugging along for "donkey" years with just
a two pin plug. So, why should you change now? Well the answer is
very simple and very short. It could save your life.
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