Surge protectors have a limited lifespan. When they’ve exhausted their strength, they may seem to be as good as ever, but they’re no longer able to do their job. To be sure your devices are protected against voltage spikes, you need to replace them periodically.
A protector’s lifetime capacity is measured in joules, a unit of energy. A protector rated at 5,000 joules will last five times as long as one rated 1,000 joules. Or to look at it another way, a fresh 5,000-joule protector will stop a surge of 2,000 joules and still have life left, while the 1,000-joule protector can’t fully stop even that one surge.
When a storm like Hurricane Irma comes through, high-voltage wires come down, causing short circuits, and buildings can get voltage spikes that are many times what’s intended. Unprotected devices in their path are toast — literally.
Normal current will keep flowing through a protector even when it’s exhausted. The next lightning bolt or transformer short could turn your computer or TV into an expensive doorstop. The way to avoid that is to get protectors with a high joule rating and to replace them on a regular schedule. Two years is long enough to keep them, less if you’re in a building with erratic power.
Today, everything has smart electronics in it, whether it’s a disk drive or a refrigerator. Inexpensive protectors can avoid the need for expensive replacements. Just as you replace the batteries in smoke detectors regularly to make sure you’re really protected, you should keep track of the age of your surge protectors and replace them when they’ve reached the end of their lives. You should also consider replacing them after a serious overvoltage incident. Get good-quality replacements so they’ll keep working as long as they’re in use. It saves money in the long run.