Dear Jim: With all the electronic items I have, I thought about installing a whole-house electric surge suppressor. What are the various types, how can I compare the various models and do they save energy? – Kerry K.
Dear Kerry: Today’s homes have more sensitive electronic devices than the most people realize. Everyone thinks of televisions, computers, DVD players, etc., but even most modern clothes washers and dryers, toaster ovens and other small appliances have sophisticated electronic components.
It is wise to install a whole-house voltage surge suppressor to protect entire branch circuits throughout your home. This does not eliminate the need for also using a plug-in point-of-use surge suppressor for the most sensitive electronic devices. Using these two levels of protection is best.
Voltage surges in your home wiring are actually called transient voltage surges by professionals. There can be hundreds of these voltage spikes every day. They are very short in duration, but can exceed many hundreds of volts in magnitude. Instead of burning out the electronics with one surge, they typically slowly degrade components and wiring insulation. This causes the electronic device to fail prematurely.
There are many more sources of these voltage spikes than just lightning. If you live near commercial operations with large motors, such as large refrigeration units or pumps, surges occur when these motors switch on and off. Even the smaller motors in the clothes washer or vacuum cleaner inside your home can generate destructive surges throughout your house wiring.
Most whole-house surge suppressors use MOV (metal oxide varistors) components which absorb the electrical energy from the surge when it gets above a certain level (clamping voltage). Below this voltage, the surge suppressor has no effect. Some companies claim a surge suppressor can lower electric bills, but the primary purpose of one is protection.
If a very powerful surge comes through, it may burn out the surge suppressor and it must be replaced, but your electronic devices are saved. When selecting a surge suppressor, consider the manufacturer’s protection warranty. Some will replace any of your electronic devices, up to thousands of dollars, which are damaged by a surge that gets through.
The most common design of whole-house surge suppressor is mounted in the breaker panel. Another common design is used as a base under the electric meter and must be installed by a professional electrician or your utility company. When replacing or adding new circuit breakers, some include surge suppression circuitry.
The amount of protection a surge suppressor gives your devices depends upon the suppressor design. More expensive models have larger MOV’s (metal oxide varistor) components which are able to absorb a higher energy surge. When a surge is larger than the MOV can absorb, the MOV burns out. When this happens, the surge gets through to your devices. Some have an LED indicator light to let you know if the MOV has been burnt out by a surge.
When selecting a surge suppressor, the best method to determine the protection it offers is to compare its performance specifications. The energy in a surge is measured in joules. The maximum surge current energy dissipation rating indicates how large a surge it can handle without burning out. A rating of 1,000 should be the minimum for a home and some go as high as several thousand joules.
Another important protection specification is the clamping voltage (usually from 330 to 600 volts). This the magnitude of the voltage spike if lets through before the MOV stars to absorb the high energy. A lower clamping voltage rating generally provides better protection for electronic devices. Many new devices are very sensitive to even relatively low voltage spikes.
Even if you have a surge suppressor installed, it is still important unplug as many electronic devices as possible during a thunderstorm. A strong voltage surge from a lightning strike can easily jump across an open switch so don’t just switch things off. It is also wise to use a separate point-of-use surge suppressors at each sensitive device for a secondary level of protection.
The following companies offer efficient surge suppressors: Asco Power, (800) 288-6169, www.ascopower.com; Belkin, (800) 223-5546, www.belkin.com; Eaton, (800) 386-1911, www.eaton.com; Intermatic, (800) 391-4555, www.intermatic.com; and Meter-Treater, (800) 638-3788, www.metertreater.com.