The Flicker Test: What £20 of Surge Protection Actually Buys You in a Storm

The lights dip, the router reboots, and somewhere in the house a games console makes a noise you’d rather not hear. British storm season has a habit of turning ordinary electrical sockets into a source of low-level anxiety. It’s also prime season for £20 surge-protected extension leads to be sold as if they’ll defend your entire home from lightning, brownouts and bad luck. They won’t. But that doesn’t make them useless.

What a £20 surge strip can actually do

A decent surge-protected extension lead is a local sacrificial layer. Inside, you’ll usually find metal oxide varistors—MOVs—that clamp sudden voltage spikes and divert some of that energy away from the sockets. Think of it as a bouncer for small transients on the mains, not a bunker.

For around £20, you should expect a BS 1363 plug and sockets, a sensible maximum load rating, and a surge indicator light. Some models quote a joule rating; others are vague. A higher joule number isn’t automatically better, but a strip with no clear rating, no brand and no indicator is closer to a placebo than protection. Look for a known manufacturer, a clear current rating, and a warranty that doesn’t read like it was written by a lawyer in a hurry.

This is the sort of device that can help protect a desktop PC, monitor, router or TV from modest switching spikes on the ring main. It is not going to stop a direct lightning strike, and it won’t keep your PC running when the power actually goes out. It also won’t fix a dodgy earth or a loose neutral. If your wiring is suspect, the answer is an electrician, not a power strip from the middle aisle.

Where cheap protection turns into a bad idea

A surge strip has a load limit for a reason. Plugging a kettle, heater or tumble dryer into one is asking for trouble—not because of surges, but because of current. Daisy-chaining strips is another classic own goal. One strip into another into another is how you create a hot plastic sandwich behind the telly.

Also check the indicator. Many MOV-based strips sacrifice themselves after a big hit. If the protection light has gone out, the sockets may still work, but you’ve lost the surge function. It’s now just an extension lead with a story. Replace it rather than pretending it’s still on duty.

And be sceptical of any £20 plug that claims to protect the whole house. It can’t. It only sees what happens at its own socket, downstream of your consumer unit. A surge arriving on the incoming supply, or through an aerial, phone line or network cable, has other routes into your gear.

The UPS question: when battery backup is worth it

If your concern is losing work, corrupting a NAS or having the router drop during a storm-related outage, a UPS is the more honest purchase. A basic standby UPS starts around £70-£100; a line-interactive model with pure sine wave output and USB monitoring costs more. For a desktop PC, NAS or home server, pure sine wave matters because some power supplies dislike stepped approximations.

A UPS gives you minutes, not hours. That’s usually enough to shut down cleanly or ride out a short flicker. It also gives you voltage regulation on some models, which can help in areas with grubby power. It will not protect against a direct lightning strike any more than a strip will, and its battery is a consumable. If the battery is four or five years old and the unit beeps under load, budget for a replacement.

Don’t buy a UPS for the whole house. Buy one for the kit that actually minds an unclean shutdown: the machine holding your files, the broadband router if you work from home, maybe the smart home hub that runs the heating. Everything else can probably cope with a brief outage.

Whole-house SPDs: the grown-up option

A surge protection device fitted at the consumer unit is the proper whole-installation layer. In the UK, a Type 2 SPD is typically installed by an electrician alongside your MCBs or RCBOs. It protects the wiring and appliances downstream from many incoming surges, and it’s the sort of thing worth discussing if you live in a rural area with overhead lines, have expensive built-in appliances, or just want a sensible belt-and-braces setup.

This is not a DIY job. It involves opening the consumer unit, checking earthing and bonding, and selecting a device that coordinates with your installation. Costs vary, but think in terms of a proper electrical job rather than a gadget purchase. A consumer-unit SPD also doesn’t make a £20 strip redundant. Local protection still has a role at the socket, especially for sensitive electronics.

Does your home insurance actually care?

This is where people often assume too much. Some home contents policies include accidental damage cover that may respond to a power surge; others exclude it, require a specific endorsement, or apply a hefty excess. The wording matters more than the advert.

Check three things: whether ‘power surge’ or ‘electrical damage’ is mentioned, whether accidental damage is included or excluded, and what proof you’d need to claim. Receipts, serial numbers and photos of the setup are boring until the day they aren’t. A £20 surge strip is not usually a policy requirement, and it won’t automatically make an insurer pay out. Don’t buy one because you think it ticks an insurance box. Buy one because it’s a reasonable local safeguard.

A sane storm-season plan

Start with the cheap wins. Use a reputable surge-protected strip for your desk and TV stack, keep it within its load rating, and don’t daisy-chain. If a storm warning is serious and you’re at home, unplug the expensive stuff—especially anything with an aerial or network cable attached. That’s still the most effective free protection.

Then decide whether your risk justifies more. A UPS for the machine that holds your work and files is sensible. A consumer-unit SPD is sensible for the house. A £20 strip is sensible for the socket. What isn’t sensible is expecting any one of them to do all three jobs. Storm season is a flicker test for your setup, not a test of how much confidence a plug can sell you.