A lot of homes probably have outdated power strips that provide little or no protection against power surges or in extreme cases, lightening strikes. The cost of providing some rudimentary protection is minimal when compared to the cost of replacing the electronic items themselves. The average retail purchase price of a 4-way surge protection strip is around 6, depending on the length of extension cable required with it. Individual surge plug adapters come in at an average price of 5.50. The price increases if you also require AV protection, which is designed to protect equipment connected to your phone line or coaxial cable connection.
Voltage spikes caused by fluctuations in the mains power supply from the power company are the main cause of damage to electrical devices. A surge protection device will harmlessly short the excess voltage to ground and away from sensitive equipment. Any surge suppression device will have a Joules rating associated with it. As a Joule is a measure of energy, this rating indicates how much of the energy caused by a voltage spike can be absorbed. The joules figure quoted on any surge strip or surge adapter can be confusing and misleading, but I would look for a figure in excess of 250 Joules and hopefully significantly more than that.
Surge suppression devices normally incorporate a Metal Oxide Varistor to divert any excess energy safely to ground. An MOV is a simple device comprising two metal oxide semiconductors that have variable resistance. When the voltage is high then the resistance in the MOV is low, therefore harmlessly directing the additional current to flow to ground. As the voltage returns to normal levels, the resistance in the MOV also increases, thus allowing normal current to flow to any attached electrical devices. The point at which the MOV will divert current away from connected devices is know as the clamping voltage, with common ratings being somewhere between 300-500 volts.
The time it takes for surge protection device to respond to an increase in voltage is known as the response time, which is normally measured in nanoseconds, whilst research has shown that voltage spikes take significantly longer to reach their peak voltage.
Now back to our original statement about the number of households with inadequate surge protection. It is important that the message goes out to the public about the advantages of using surge suppression equipment, and the possible consequences of not investing in it. A few pounds investment could save hundred or thousands of pounds in damaged equipment. Even if the devices are covered under an insurance policy, there is also the inconvenience of being without your treasured home entertainment system while an insurer processes the claim.
On a final note, surge protection devices that commonly use MOVs, have a limited lifespan depending on how many voltage spikes they experience and the severity of them. Good surge suppression products will have an indicator light to provide a visual indication that surge protection is being given. If those visual indicators suggest that the device is faulty or worn out, then it is time to replace the device. No real time period can be put on the life expectancy of a surge strip, because it is really down to the quality and reliability of the mains power supply itself. If you are not using surge protection, then I would seriously recommend that you consider It soon.