Our previous article discussed personal lightning safety both outdoors and indoors and the need to observe When Thunder Roars Go Indoors! In this article discussion focuses on indirect lightning strikes that can enter your home via multiple paths and can cause damage to appliances and sensitive electronic equipment.
What is an indirect Lightning Strike?
A nearby direct lightning strike (proximity) may hit your neighbor’s house, a flagpole, a fence or wall, a tree, the ground, or some other nearby object. Because lightning is seeking the least resistant path to ground it can cause a surge into your home. Indirect lightning strikes are more frequent and less severe than direct lightning strikes which will be discussed in our next article.
The path into your home from an indirect lightning strike can be your electric service, cable/satellite service, telephone service, gas service, or even the water lines, and in some cases the powerful electromagnetic field can induce a surge into the home.
And because Lightning Loves Technology it is capable of destroying sensitive electronic components in computers, TVs, garage door operators, furnace and A/C controllers, motorized chairs and sofas, irrigation systems, refrigerators/freezers, sound systems, microwave ovens, telephone answering machines, corded telephones, car and golf cart charging stations, radios, electronic games, and other appliances.
In accessing your level of risk to your valuable appliances and electronic equipment you may wish to consider both Primary and Secondary Surge Protection.
What is Primary Surge Protection?
Primary Surge Protection protects the 220-volt “hard wired” equipment that you do not plug into a 120-volt wall outlet including your furnace, A/C, electric dryer. It also provides protection for motors in your refrigerator, freezer, and washing machine.
There are two ways to achieve primary protection. You can rent a Surge Protection Device that your electric utility will install behind your exterior electric meter. Alternatively, you can contract with a licensed electrician to install a surge protector on a 30-amp dedicated two-pole breaker on your electric panel in the garage.
WARNING! This is not “whole house” surge protection. As good as these surge protection devices are even a small surge may get past it on the electric service. Or a surge can come from the telephone or cable/satellite service. Therefore, you need Secondary Surge Protection.
What is Secondary Surge Protection?
Secondary surge protection is sometimes called “point-of use” (POU) or “plug ins” that you plug into a 120-volt wall outlet. The graphic below shows secondary surge protection to protect a TV. It is important that the cable or satellite coaxial cable be connected from the cable wall outlet to the surge protector and a second connection is made from the surge protector into the cable or satellite receiver. The same concept applies to telephone lines supporting a computer and a telephone answering machine.
The POU devices can be purchased at hardware, electronics, big box stores, and online. When purchasing POU devises consider only those labeled “Type 3, UL 1449”.
The above will NOT protect you from a direct lightning strike to your home and is the subject of the next article.
The above is the current state-of-the-art, but safety is never absolute. It should be recognized that anything man-made can fail but the equipment discussed above does function as designed an extremely high percentage of the time.
As a homeowner you should conduct your own due diligence for your lightning risk.
Villager Len Hathaway is a recognized expert on lightning.