How do I protect my devices from power cuts and surges?

Two different things get conflated here. A power cut is a loss of supply, and its main risk is to whatever was being written at the time. A surge is a brief spike in voltage — from lightning nearby, or from the supply being restored — and its risk is to the electronics themselves. They need different answers, and the honest position is that most households need very little.

Safety

Step by step

1. Be clear about what a power cut actually risks.Modern devices tolerate losing power. What does not tolerate it is a file part-written, a database mid-update, or a drive that was reorganising itself. Laptops, phones and tablets are effectively immune because they have their own battery.
2. Make backups the first line of defence.Everything else in this guide reduces the chance of a problem; a backup is what makes the problem survivable. A working backup is worth more than any protective hardware you can buy.
3. Use a surge-protected extension for the expensive corner.The television and AV rack, and the desk with the computer and monitors. A protected strip is inexpensive and takes the edge off spikes. It is not a guarantee against a direct lightning strike, which nothing plug-in will stop.
4. Know that surge protectors wear out.The component inside absorbs energy and degrades each time. Most have an indicator light showing protection is still active; if there is no light, it is an extension lead rather than a protector. Replace them after a serious event and every few years.
5. Consider an uninterruptible supply only where it earns its place.A small one gives a desktop and its screen a few minutes to save and shut down cleanly, and keeps the router and a network drive alive through brief cuts. It is worth it where outages are frequent, where a desktop holds live work, or where a network drive is doing the household's backups.
6. Protect what matters, not everything.A desktop, a network drive, and the router if you rely on it are the sensible list. Putting laptops, phones and printers on an uninterruptible supply achieves nothing useful; they either have batteries or do not care.
7. Set devices to restart correctly after power returns.A network drive, a desktop that runs backups and anything on a shelf that is awkward to reach usually has a setting for what to do when power is restored. Setting it to power on saves a trip and means overnight jobs still happen.
8. Remember the phone line in a cut.A digital phone service runs through the router and stops in a power cut unless a battery backup unit is fitted. Households where someone depends on a phone should raise this with their provider rather than solving it with a computer accessory.
9. Deal with a wet or storm-damaged device properly.If lightning has struck nearby and something is dead, do not open it looking for a fuse. Unplug it, note it for the insurance, and have it assessed. Damaged mains equipment is not a household repair.

Tips

• Frequent brief flickers are harder on equipment than one long cut, and are worth mentioning to the network operator — the fault is often on their side and they will investigate.
• If the household has a network drive doing the backups, that is the one device where an uninterruptible supply earns its keep, because a cut during a write is the worst possible moment.
• Check the batteries in any uninterruptible supply every couple of years. They are consumables and a failed one gives no warning until it is needed.

Common mistakes

• Assuming a surge-protected strip protects against everything — It reduces moderate spikes. A close lightning strike can arrive through the aerial lead, the phone line or the earth as easily as through the mains, and nothing plug-in will stop it.
• Daisy-chaining extension leads to reach a socket — It is a fire risk regardless of any surge protection, and it defeats the protection anyway. Use one properly rated lead of the right length.

If it doesn't work

Questions people ask