Originally Published: July 21, 2011 9:55 p.m.
Q: With monsoon madness, what should we do about lightning protection? - Harold and Margaret, Chino Valley
A: Surge protection has become a much more complex and important issue in recent years because the value of electronic equipment in a typical home has increased enormously. Our equipment is also more vulnerable to surges produced by lightning, because it is networked with other equipment inside and outside the home.
A single bolt of lightning can carry over 30 million volts of electricity. Lightning can rip through roofs, cause structural damage, ignite fires and wreak havoc with electronic equipment. Residential lightning losses exceed billions of dollars annually and represent 5-8 percent of all residential insurance claims.
There are four ways in which a lightning strike can damage residential equipment. The most common damage comes from a lightning strike to the network power - phone and cable TV - commonly known as CATV wiring. This network, especially if it is elevated, is a main collector of lightning surges. These surges are then transferred directly into the home and then to all of your connected equipment.
The next most common mode of lightning damage is when strikes travel through the ground and connect to your underground cables and pipes, and also connect to external wiring such as air conditioners, exterior lights, gate control systems, electronic dog fences, and security systems, all of which can be struck by lightning and then carried into the home.
A third scenario occurs when lightning strikes nearby objects, such as trees, flagpoles and signs that are close but not directly connected to the house. When this type of strike occurs, the lightning radiates a strong electromagnetic field, which can be picked up by wiring in the house and can damage equipment.
The last mode of damage is a direct lightning strike to the house. This type of strike is rare.
Our national electric code requires certain grounding, bonding and protection features that are intended to protect against lightning. These safeguards greatly reduce personal injury; however, they are somewhat inadequate to prevent damage to electrical and electronic equipment.
To protect your home, there are lightning protection systems, surge protectors on the AC power wiring, additional surge protections on signal wiring, and point-of-use protection at the equipment being used.
The lightning protection system is only useful in the extremely rare direct-strike scenario. The AC and signal surge-protection systems collect the major part of the lightning surge and then direct this surge harmlessly into the building ground. These protection systems greatly reduce the burden on the point-of-use protectors at the equipment. It is important to keep in mind that the effectiveness of this protection system depends on the integrity of the building wiring. A good surge-protection system installation should include testing of all receptacles to be used. Most new homes are built with power, phone and CATV entry points close to one another; this is very desirable and makes it easy to mount the AC protectors and signal protectors close to the main building.
Whole-house protection, sometimes called a complete home surge system, is becoming more popular. A lightning-protection system properly installed can protect and prevent potential lightning damage up to 99 percent.
Unplugging electronic and phone lines during storms is advisable, as recommended in an informative article by the Prescott Computer Society in the July 10 edition of the Courier.
If you have any concerns that your home is not properly protected, a YCCA member electrician will be happy to assist you to make sure your home is in a bubble of protection.
Yavapai County Contractors Association (YCCA) is a professional association representing licensed, bonded and insured contractors, suppliers, distributors and business entities. Call YCCA for information on hiring a contractor at 778-0040. Submit questions to email@example.com or through www.ycca.org.