How to Prepare for a Power Cut or Blackout

On 28 April 2025, shortly after midday, the entire electricity system of Spain and Portugal shut down. Power was out for around ten hours across most of the peninsula, and longer in places. Trains stopped, traffic lights went dark, mobile networks struggled and card payments failed. Nobody had any warning.

Most power cuts are shorter and more local than that, but they share its most important feature: they arrive without notice, so whatever you do about them has to be done beforehand. This guide covers what to prepare, what to do in the first hours, and how to get through a longer outage safely.

Before: the ten-minute version

If you do nothing else, do these. Each is drawn from UK Government or US Ready.gov advice.

• A torch in a known place, with spare batteries. The UK Government notes torches are safer than candles. One by the bed and one near the fuse box is a good start.
• Save the number to report a cut. In England, Scotland and Wales it is 105, free from any phone. In Northern Ireland it is 03457 643643. Elsewhere, find your network operator's number now.
• Keep a power bank charged, and a battery or wind-up radio for updates if the mobile network struggles.
• Some bottled water and food that needs no cooking, plus a manual tin opener.
• Some cash. Card machines stop working when the power does.

If anyone depends on electricity for their health

If someone in your home uses powered medical equipment, such as a home oxygen concentrator or a ventilator, the UK Government advises making a plan with their care team now. In Great Britain, sign up to your energy supplier's free Priority Services Register so they know you need extra help during a cut. In the US, Ready.gov advises talking to your medical provider about a power outage plan. Do not wait for an outage to find out what the battery backup lasts.

During: the first hours

• Check whether it is just you. Look at your fuse box or consumer unit for a tripped switch, then check whether neighbours or street lights are also off.
• Report it on 105 in Great Britain, or to your network operator.
• Keep the fridge and freezer closed. The USDA says a closed fridge keeps food safe for about 4 hours, and a full freezer holds its temperature for about 48 hours, or 24 if half full.
• Unplug sensitive electronics so a surge when power returns does not damage them. Leave one light switched on so you know when it is back.
• Save your phone battery: low power mode, low brightness, messages rather than calls.
• Use torches, not candles.
• Check on vulnerable neighbours, as the UK Government suggests, and share blankets or supplies if you can.
• Keep away from fallen power lines and report them to the emergency services.

A longer outage

Once a cut runs past a few hours, the priorities shift from inconvenience to food safety, warmth and water.

Food

Eat from the fridge first, then the freezer, then your shelf-stable supply. The USDA's rule is to discard perishable food that has been above 4 °C (40 °F) for more than two hours. Ready.gov's summary is shorter: when in doubt, throw it out. Do not taste food to check it.

Warmth, or keeping cool

In winter, gather everyone in one room, close the doors to the rest of the house, and use layers and blankets. See our guide to extreme cold. In summer, stay on the lowest floor, keep curtains closed during the day and drink regularly.

Water

Mains water usually keeps flowing in a power cut, but not always. Homes on a private well with an electric pump, and some tall buildings that rely on pumps to reach upper floors, can lose water with the power. If that applies to you, your stored water is your supply. Our water calculator shows how much to keep.

Communication

Mobile networks rely on power too, and during the Iberian blackout they were disrupted across both countries. Agree in advance where your household will meet if you cannot reach each other, and keep a battery or wind-up radio for official updates.

When the power comes back

• Plug things back in gradually rather than all at once.
• Check the fridge and freezer are cooling, and go through the food using the two-hour rule above.
• Recharge everything: power banks, torches, phones.
• Replace what you used and write down what you wished you had. That list is the most useful preparedness document you will ever own.

That last step is where most households fall down, because the list gets written on the back of an envelope and lost. The Power Outage plan in StayReady Kits is free, walks through the before, during and after steps on this page as a checklist, and keeps your supplies and their expiry dates in one place so restocking is a matter of looking at what is missing.

Common questions

Who do I call in a power cut?

105 in England, Scotland and Wales, free from any phone, or 03457 643643 in Northern Ireland. Elsewhere, your network operator. For danger to life, the emergency services.

How long does food last in a power cut?

About 4 hours in a closed fridge, and about 48 hours in a full closed freezer (24 if half full), according to the USDA. Discard perishables that have been above 4 °C (40 °F) for over two hours.

Are candles safe?

The UK Government advises that torches are safer than candles.

Can I run a generator in the garage?

No. Outdoors only, at least 6 metres (20 feet) from any door, window or vent, according to the CDC.