Several years ago, when home computers came into wide use, consumers began to get into the habit of purchasing surge protection power strips to use with the computer system. In many homes, the computer, laptop, or HDTV system wis the main system with sensitive electronics that needed protection from power surges. The use of switchable surge protection power strips has been an inexpensive “low tech” solution due to the limited number of devices needing protection.
With the increasing popularity of smart home technologies, sensitive electronics are now found in several devices that are integrated throughout the home, including lighting and security systems, integrated home audio and video systems, and smart appliances. Many of these systems are hard-wired into the home power distribution system, making it impossible to use power strips with surge protection built-in.
Because most smart technologies in the home contain electronic components, they are vulnerable to power surges. Power surges in a home containing a number of programmable smart devices can result in damage to these systems, resulting in expensive repairs. Hence, homeowners with extensive intelligent systems in their home are well-advised to consider a surge protection system that will provide protection throughout the home, not just for specific devices or appliances at a single power strip.
Whole house surge protection units can be mounted near the breaker or fuse box, or on the rear of the electric meter. In some markets, the power company will provide a meter-based surge protection unit for a small additional monthly cost.
How serious a problem are power surges? According to the National Institute of Science and Technology (NIST) in the U.S., there are two sources of power surges – lightning surges and switching surges.
Lightning surges can occur due to a direct lightning strike, which usually has a short lived, minimal effect if the home electrical system is well protected, or indirect lightning strikes, which can propagate considerable distances along electrical or cable lines, and have undesirable effects. The frequency of lightning surges depends on the geographical location of the home and how often thunderstorms strike.
Another type of power surge is the switching surge, power surges within the home due to the switching on and off of high power usage devices. Sometimes, the switching of devices is due to an action by the homeowner – say, in the case of using power tools; while other times, the switching is automatic in the system, like a heater fan or blower whose switching is controlled by a thermostat.
While whole house surge protection units will protect the electrical power distribution circuits within the home, they may not protect against lightning surges that enter the home through the cable, phone, or satellite system. One of the most vulnerable systems in the home is the TV/set top box that has a cable or satellite connection, particularly if the cable enters the home at a different physical location from the electric power. When this is the case, there may be voltage differences introduced between the two systems, which are in close proximity in the home.
Homeowners can minimize the risk by checking with the service providers to see that the systems have a common earth ground and enter the home at the same point. The figure illustrates a practical arrangement for common grounding of multiple systems within a home that will minimize the risk of destructive power surges due to systems with more than one source of external connectivity.
Figure 1: Schematic of suggested grounding system. Source: NIST special publication 960.6.
As homes of the future become more connected, and structured wiring systems are used throughout the house for multiple applications, these homes will become more vulnerable to power surges. It is important that installers of these systems and building contractors understand the use of common grounding systems and whole house surge protection as integral parts of the future home.Log in to post comments