Do Surge Protectors Go Bad?

A surge protector in a power strip can eventually lose its ability to protect electrical components over time, even though the power strip itself continues to transfer electricity. This situation can make consumers vulnerable to fires or short circuits.

Normal Operation

A surge protector uses a device called a metal oxide vaporizer, or MOV, to trap and divert excess voltage from electrical spikes. This diversion protects computers and other sensitive electronic devices from overloading.

Wear and Tear

After many electrical surges, the MOV in a surge protector will eventually wear out. A surge protector equipped with an indicator light will signal when the surge protection has failed.

Hidden Dangers

Some surge protectors do not come with warning lights, making it impossible to tell whether they still offer protection. In some cases, a failing MOV can even overheat the surge protector and start a a fire.


New Mexico State University recommends surge protectors rated for at least 600 joules of protection and a response under one nanosecond. A protector should also include an indicator light and a polarized or grounded plug.