January 11, 2006
FOR IMMEDIATE RELEASE
Lightning Strikes, Inadequate Wiring, Poor Grounding and Transient Voltages are Concerns for Owners of High-Tech Homes
ORLANDO, FL— Not long ago, electrical power quality - or PQ for short - was a concern only for a select few in government, business and industry. Now, PQ is coming home.
The responsibility of most electrical utilities ends at the meter, where electricity enters the home. In most parts of the USA, barring brownouts or lightning strikes, the customer normally can purchase reasonably clean electricity by the kilowatt-hour from their local electric utility.
What happens inside the home is another matter. According to the Copper Development Association, electrical power quality can be compromised within a home in several ways, including lightning strikes, inadequate wiring, poor grounding and transient voltages due to motors or printers.
Lightning strikes are potentially the most damaging and the most difficult to protect against. A lightning protection system includes lightning rods, conductors, low-resistance grounding electrodes and several stages of surge protection. Anyone living in a lightning-prone area should consider investing in a complete system; for others, a good-quality surge protection system should suffice. A good source for information on lightning protection is the Lightning Protection Institute (www.lightning.org).
Inadequate wiring in the home can cause excessive voltage drops. Often, not enough branch circuits run back to the electric panel, or the wire gauge is too small. Some large appliances may share the same circuit as sensitive loads. When a large appliance such as a refrigerator, a unit air conditioner or laser printer is turned on in one location, then the voltage may dip someplace else, causing a computer to crash, for example.
The remedy is to run more branch circuits and/or use fatter wires (a lower AWG number; e.g., using AWG 12 instead of AWG 14), especially for long-distance runs. If wires are changed then breakers should be adjusted accordingly. A new high-end "tech home" may have 30 or more branch circuits compared with four or five branches for a 1950s vintage dwelling. The right number of branch circuits to ensure good PQ lies somewhere in between.
Transient voltage surge suppressors (TVSSs), also known as surge protection devices (SPDs), can be installed to filter out "transients," which are short-term deviations from normal voltage levels. Many kinds are available at many price points. SPDs can be used effectively throughout the home, and in some cases two layers of surge protection can be beneficial, for example: one for the whole house at the main breaker panel and one at the outlets serving your electronic equipment.
Inadequate grounding can also cause performance problems. All ground wires (third wires) must be ultimately connected to the earth through a low-resistance conductor. A "floating" ground, that is, an unconnected ground, can cause electronic equipment to malfunction.
The importance of proper grounding should not be overlooked. SPDs will not function properly unless properly grounded. Furthermore, many people do not realize that communications wiring systems also must be grounded, including phone lines, coaxial cables, structured wiring, television antennae and satellite dishes. Electrical wiring and communications wiring should be connected to the same grounding system.
"Good power quality begins with good wiring in the home," says David Brender, national program manager for the Copper Development Association.
"Older homes often lack the infrastructure necessary for optimal performance of today's electronics."
Call a local electrician to get a checkup for your home electrical wiring. Meanwhile, for more information about residential electrical wiring, visit the Building Wire section on the CDA website.
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