What is a power surge?The power that is delivered to your wall outlet is known as "120 volt AC" (alternate current). While the power company tries to maintain uniform voltage, events occur that will cause that voltage to surge or "spike." The culprit might be lightning, short-circuits, or downed power lines that cause the voltage to jump hundreds or thousands of volts.
Potential dangers
Household appliances are designed to run on 120 volts with a little tolerance plus or minus. When a power surge hits an appliance designed to run on 120 volts the results can range from a simple blown power circuit - to damaging appliances and controls - to an outright fire. All of these are frustrating, disruptive, and potentially costly.
Normal power disturbances
We have become accustom to "normal" but occasionally, for a short time, voltage will deviate from the norm.
Sags - Sags occur when the power dips below the standard 120 volts. Generally, sags do little more than cause a computer to crash, confuse some digital clocks and cause other electronic appliances to scramble their settings.
Swells - Swells are a short-term increase in line voltage. A short swell might disrupt sensitive appliances a long duration swell could cause damage.
Noise - Noise is a catch-all phrase for an occurrence that is a non-damaging nuisance.
Outage - Outages (power blackouts) can be damaging when they are unexpected and unplanned for.
The more sophisticated the electronics, the more sensitive they are to power surges and/or interruptions.
There are multiple sources of power for services within your home and each offers a different path for surges and requires different methods of protections.
Power - Electronic appliances that are connected only to power usually come with an internal first-line of surge protection provided by the manufacture. Power strips that offer additional protection are easily available at the local home store.
Communications - Electronics that are connected to a signal in addition to power require additional protection. These would include telephones, cable TV, satellite receivers and to a lesser degree intercoms, automatic sprinklers, garage door openers, and intrusion or fire alarms.
Types of surges
There are two types of surges: lightning and switching surges.
Direct lightning - Direct lighting strikes are localized to a specific area and their effect is also generally localized. Lightning rods offer protection for physical structures such as buildings, trees and towers but they will not prevent surges in wiring. Well protected electronics can survive direct lighting with little to no damage.
Indirect lighting - While not as threatening as direct, indirect lighting can cause disruptions of many household electric appliances and have has been known to frequently open garage doors.
Switching surges - These surges generally occur when power is switched on or off in the home or by the power company. The switching causes a momentary power surge in the line that can be evidenced by a brightening in the lights or dysfunctions in other electron appliances.
Surge Protection
There are three points of protection to consider, in addition to that provided within your electronic appliances:
At the plug - purchase plug-in surge protectors for your critical appliances;
At the electrical panel - Install a surge protector at the service entrance panel;
At the meter - Have the power company install a surge protector next to the meter.