Question: We have many electronic gadgets in our house, and I am concerned about a voltage surge ruining them. How can I protect these sensitive devices?
Answer: Although rare, electrical surges — usually caused by lightning strikes—can damage more than sensitive home electronics like computers, game consoles, stereos and home entertainment systems. They can also fry basic household appliances. Nearly every electric item in a modern home, right down to kitchen ranges, dishwashers, vacuum cleaners, air conditioners and fans, has components that can be damaged by a sudden spike of current.
Whole-house surge suppressors are the best option for protecting your home electronics and wiring from the damage created by lightning strikes, and there are several types from which to choose. Some mount on the circuit breaker panel indoors or are built into a circuit breaker, while others are designed to mount at the base of the electric meter. Obviously, installing these devices should be left to a professional electrician. Call your electric cooperative for advice on the best type of surge protector for your home as well as recommended professionals who can do the job safely and efficiently. Some cooperatives even sell the devices and will install the unit for you.
Properly installed, whole-house surge suppressors work by diverting power spikes before the excess current gets to your internal wiring. To do this, they use metal oxide varistors (MOVs) that dissipate the excess current. You can conceptualize them as a floodgate. At normal voltages, the gate is closed, preventing leaks. But if the voltage gets too high, the gate opens, allowing the excess current to pass to ground, protecting the devices and appliances in your home.
The ability of an MOV to dissipate a power spike is measured in joules, and the higher the rating, the more protection it offers. Another number to look for when comparing devices is clamping voltage. This is the voltage that is required for the “floodgate” to open, and here a lower number is usually better. In the event of a large surge of power, the MOVs will likely burn out as they act to protect your electronics. Look for models that have an indicator light to let you know when the unit needs to be replaced.
One word of caution: The voltage and current spikes from a single lightning strike are enormous, and there are typically many strikes during a storm. If your house experiences a direct hit by lightning, even the best surge suppressor may be overwhelmed.
Whenever a storm is forecast and you begin to hear thunder in the distance, unplug as many of your electronic devices as possible. Just switching them off may not be adequate protection—a huge voltage surge can arc across an open switch and still fry the electronic components in an expensive device. Don’t forget to unhook other external lines like satellite, cable, phone and network connections. They can serve as a path for a surge to enter a sensitive device, and they bypass the circuits protected by surge suppressors installed on the power line.
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The following companies offer efficient surge suppressors:
Eaton, (800) 386-1911
Emerson Network Power, (800) 288-6169
Intermatic, (800) 391-4555
Maxivolt, (800) 583-04773
Meter-Treater, (800) 638-3788