Thunderstorm: how to protect your electrical devices

Unplug before it starts, then wait it out.

The answer in 2 lines. Lightning can cause power surges that come in through the mains, the phone or broadband line and the TV aerial cable. Before a thunderstorm arrives, unplug sensitive devices, including the router and aerial lead. During the storm, do not touch plugs or plugged-in devices, and avoid using a corded landline phone. Surge-protected extension leads help a little; for lasting protection of the whole home, ask a registered electrician about a surge protection device in your consumer unit.

The first 3 steps

Before the storm, unplug the broadband router, computer, TV and set-top box, including the aerial cable.
During the storm, stop touching sockets and plugged-in devices, and avoid using a corded landline phone.
Afterwards, plug things back in one at a time, and note anything that no longer works.

Stop: danger

During the storm, do not unplug or touch plugged-in devices or sockets: wait until it has passed.
Burning smell or smoke after a lightning strike: switch off at the main switch if you can do so safely, get out and call 999.

Which protection for what?

Unplugging before the storm: fully protects what is unplugged. You need to do it in time.
Surge-protected extension lead: limits small surges on the mains for the devices plugged into it. It does not stop a direct strike, and does not protect via the aerial or phone line unless it has those sockets too.
Surge protection device (SPD) in the consumer unit: fitted by a registered electrician, it protects the whole installation against surges from the mains. Many new or rewired installations already have one.

Staying safe in a thunderstorm

Stay indoors and away from windows.
Avoid using a corded landline phone during the storm.
If you are outside, go indoors or into a hard-topped car; stay away from trees, water and metal fences.
Check Met Office warnings before going out.

What not to do

Unplugging in a hurry when the storm is already overhead.
Relying on a cheap extension lead as your only protection.
Trying to repair a device damaged by lightning yourself.

Good to know

A surge protection device that has "worked" during a storm may need replacing: an electrician can check its indicator.
Device damaged by lightning: take photos, get a repairer's report, and contact your home insurer (accidental damage or storm cover depends on your policy).
Power cut during the storm? Call 105, free.

In Birmingham, the Met Office issues a yellow thunderstorm warning for the evening. Before it arrives, Josh unplugs his router, his TV and its aerial cable. During the storm, he leaves everything alone. Two houses down, a neighbour's router has died; Josh plugs his back in the next morning without a problem.

A made-up story, for illustration.

Bobby

Sources, verification, confidence

Verified on 18 October 2026, for England. Confidence: high for the safety advice during a thunderstorm; medium for how well each type of surge protection works, which depends on the installation. Whether a surge protection device is required depends on wiring regulations: ask a registered electrician. This guide describes common cases, not a diagnosis.