Beware of zombie surge protectors
Many municipal offices and schools use power strips with built-in surge protectors to power and shield their laptops, computers, smart phones and other sensitive electronic equipment from voltage spikes or transients, caused by lightning or power line problems.

While very cost effective for most uses, the electronic components in surge protectors are only able to absorb a finite amount of electrical energy, and, once that limit is reached, the surge protector will no longer protect the equipment that is plugged into it -- even though the outlets may be LIVE-- and still supplying power. 

A typical surge protector is rated in units of energy called joules. If a surge protector has 1,000 joules of protection, that means it can absorb ten 100 joule hits, or one 1,000 joule hit. The more joules it is rated for, the more protection it provides.  

How to identify zombies
In many power strip models, an easily overlooked LED lamp is the ONLY indication that your surge protector is still protecting your expensive laptop, computer, or smartphone. In these models, the LED lamp turns OFF to indicate the end of surge protector life. Some models are designed to stop supplying ALL power to your equipment when the surge protector fails. Many models, however, will continue to function like a plain power strip, and unbeknown to you, aren't protecting your equipment. (A dark LED is especially easy to miss if the power strip/surge protector is out-of-sight on the floor or behind your desk.)

The living dead
The SURGE LED is off on this device, indicating that its surge protection circuity has burned out and is dead. However, the outlets are live -- and still supplying power to plugged-in equipment. The next victim? The device plugged into it during a voltage spike! 

When should you replace your surge protector?
Because their lifespan is measured in joules, not time, there is no simple answer. The older the surge protector is, the more likely it has failed or it is near the end of its service life. If your facility has weathered a serious electrical storm or other power line problem since you first plugged in your surge protector, consider replacing it now or inspect it to see if the LED indicates it is still working. 

The start of summer, with its more frequent thunderstorms and severe weather, is an especially good time to check your surge protectors so that your electronic devices are protected at a time when they are most needed for emergency response.

Some recommend replacing surge protector every two years, just in case. As for any electrical device, read the instruction manual for information on its specifications and proper operation.

Download the Surge Protection poster pdf.

Some common misconceptions about power surges

Myth: As long as my building or the power lines to it are not directly hit, my equipment should be ok.
Even if the lightning strike does not directly contact the building or the power lines into your building, the secondary effects of lightning, including earth current transients, atmospheric transients, secondary arcing, electromagnetic pulse or EMP and ground potential rise, (GPR) can degrade or destroy electrical system components. Current induced by a lightning ground strike close to a building has been know to flow in through the ground wire and destroy equipment.  

Myth: As long as I plug my devices into a surge protector, my equipment should be ok.
Voltage spikes can come in over any line, including phone and cable lines and damage equipment. Some higher-end surge protection devices offer protection for phone and cables lines. They may also include built-in EMI/RFI protection for these lines. All surge protectors must be adequately sized, rated, and fully functional to offer protection.

Unplugging the device offers the best protection of all.

If you are in an area or building that is prone to lightning strikes (for example, located on a hill) or you need surge protection for heavy equipment, data centers, etc, consult an electrical professional.