How long does a surge protector last?

A surge protector does not have a set lifespan in years. It lasts until its protective parts are used up, and that depends on how many surges, and how much high voltage, it has had to absorb. One protector can last a long time in a quiet house; another can be spent after one bad storm. The reliable way to know is the protector's own indicator lights, so the real maintenance job is knowing what they mean and checking them.

Why surge protectors wear out

NIST's homeowner guide puts it plainly: many, if not all, electronic components will age and have a limited life.^[1] It says well-designed surge protectors might reach the end of their life early if exposed to some exceptionally high and rare stress.^[1]

Surges are not the main killer, though. NIST reports the view among specialists that most of the rare catastrophic failures of surge protectors are caused by excessively high line voltage that can occur when there is a fault on the power system,^[1] and that failure from a very large surge is less likely than failure from high line voltage.^[1] For whole-house units, wiring matters too: Siemens's installation notes say neutral-to-ground bonding not done to the NEC will fail surge devices, and calls it the leading cause of their failures.^[3]

What the ratings tell you about life

A bigger rating gives more margin, not a set number of years. NIST explains that joules are a simplified measure of the surge energy a protector can dissipate without damage to itself, and the higher the value, the more energy it can handle,^[1] and that typical values range from about 100 joules to 1,000 joules or more.^[1] It also notes that somewhat higher clamping voltages, such as 400 volts or more, can still protect electronics while making the protector itself less susceptible to damage from swells.^[1]

Know what the lights mean

On one APC model, the user guide says: "If the LED is not illuminated the surge suppression circuitry has been compromised."^[2]

What the protector does at the end of its life varies. That APC guide says: "This device will disconnect the surge protective component at the end of its useful life. It will not continue to supply power to connected equipment."^[2] Other designs behave differently. NIST explains that some protectors cut off power when their protective element fails, while others disconnect the failed element and keep powering your equipment.^[1] With the second kind, the TV keeps working and nothing tells you the protection is gone except the light. NIST's own question is the right one: if the protector keeps power on, how often will you look under or behind your desk to check that the protection light is still on.^[1]

NIST adds that indicator lights are not standardized, so save any card that explains them.^[1] Some devices make it easier. Leviton says its surge receptacles have an audible alarm, so you are notified when you need to replace the surge outlet.^[4]

Whole-house units signal too. Siemens says its whole-house units let you know when they are worn out: the green lights go out, a red service light flashes and an alarm beeps.^[3] On those units, the same red light flashing and beeping with the green lights still on warns of a compromised neutral-to-ground bond,^[3] which is a wiring problem, not a worn-out protector. The unit in the photo above is labelled as protecting only when both of its green lights are lit.

Simple habits that make them last

• Check the lights on every protector now and then, and after any severe storm or power company fault.
• Watch for wiring warnings. On the APC model, a Ground OK light that goes out means the unit has detected a wiring fault,^[2] and the guide says to stop using it and have a qualified electrician correct the building wiring.
• Use it as designed. APC's guide says: "Do not plug extension cords into the SurgeArrest."^[2] It also says not to install it where there is excessive heat or humidity.^[2]
• Keep the paperwork. APC warrants that model against defects for the lifetime of the original purchaser, limited to repairing or replacing the product,^[2] and Siemens advertises a 10 year product and connected equipment warranty on its whole-house units, subject to its terms.^[3] Receipts and the card explaining the lights belong in the same drawer.
• Retire strips with no light. An old strip with no protection indicator gives you no way to tell whether it still protects.

When to call a licensed pro

A plug-in protector whose light is out is simply replaced. A whole-house unit is different: it is connected at the service panel, and CPSC tells homeowners not to remove the service-panel cover, because that is a job for a qualified electrician.^[5] Virginia defines an electrician as a tradesman who does the construction, repair, maintenance, alteration or removal of electrical systems regulated under the building code,^[6] and no individual may work as a tradesman unless licensed.^[7] Call one when a panel unit's lights go out or it alarms, when a protector reports a wiring or grounding fault, or after a storm that damaged equipment. Our answers on how a whole-house surge protector works and why electronics get damaged even with a surge protector explain what the electrician will look at.

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