Why you should unplug your PC during a power outage

Power outages usually strike without warning, and most people think about finding a flashlight rather than protecting their electronics. But if a PC stays plugged into the wall, it can still be damaged even if it has already shut down on its own.

The issue is that a powered-off computer remains connected to the home's electrical wiring, and that connection is exactly how damage can occur, affecting sensitive parts like the motherboard, RAM and SSD. Voltage can fluctuate sharply both before and after an outage, and the surge that arrives when power is restored is often more damaging than the outage itself. Standard US household circuits run at 120 volts, and even a moderate spike above that level can permanently damage sensitive components.

Turning off isn't enough

Even a PC that was switched off before an outage isn't necessarily safe, since electricity can still travel through the cord once power returns. The most common cause is a power surge, often triggered by lightning or damage to nearby power lines, even a strike that doesn't hit the house directly. If a PC is running when power cuts off, the sudden loss can corrupt files being saved, potentially disrupting operating system updates, and can also damage the mechanical heads in hard disk drives.

How to protect a PC

When severe weather is expected or an outage has already occurred, it's advisable to shut down and unplug the PC from the wall. The same applies to routers and other expensive electronics like TVs. Stronger protection comes from a quality surge protector, which absorbs voltage spikes, or better still, an uninterruptible power supply (UPS), which combines surge protection with a battery backup, giving users time to save their work and shut down properly. For broader protection, a licensed electrician can install surge protection directly into the home's electrical panel.

When power returns, it's best to wait a few minutes before reconnecting devices, plugging in the surge protector first, followed by the PC and other peripherals.