Why do repeat power cuts happen?
Repeat power cuts can happen for many reasons, most often, they’re caused by a fault on an underground cable. Underground cable faults are caused by damage to the cable, which can be difficult to find. This may be the result of third‑party damage (such as digging), general wear and tear, or changes in weather conditions.
Faults on overhead lines are usually caused by strong winds, trees touching or falling onto the lines, third‑party damage, or objects coming into contact with the network.
In most cases, power cuts are repaired when the fault first happens, however, some faults are more difficult to locate. These are uncommon, but they can be challenging to repair because they don’t always leave clear signs once the power is restored.
When power cuts happen, we carry out investigations to understand what’s causing the problem. This may include:
Installing fault‑finding equipment at your local substation:
We may install specialist equipment that can automatically replace fuses, helping to restore your power more quickly if another power cut happens. You may experience this as a short power cut, lasting up to 3 minutes. At the same time, the equipment sends us data that helps us understand how the fault behaves over time and tells us where it’s likely to be.
Monitoring electricity usage:
We may take load readings or install additional equipment at your local substation to monitor electricity usage and check how the network is performing.
Analysing past power cuts:
We review data from previous power cuts, looking at patterns such as when and where they occurred, to help identify possible causes.
Using advanced detection techniques:
In some cases, we drill small holes in the ground to detect gases released when a fault occurs. We may also use thermal imaging equipment to look for signs of heat underground that could indicate a fault.
Inspecting overhead power lines:
Our engineers may visit the area and walk along overhead power lines to check for anything touching or interfering with them, such as trees or other objects.
Sometimes this work helps us rule out certain causes before we can identify the exact problem. While this can take time, it helps ensure the correct and long‑term repair is put in place.
Once we’ve located the fault, we’ll first assess the situation to make sure it’s safe.
If the fault needs urgent repair because it could cause a potential safety risk:
We’ll switch the power off and carry out the repairs as soon as possible. Turning the power off is necessary to keep you, the public, and our engineers safe.
If the fault is safe to manage, we’ll:
- Plan a date for the repair work to be completed
- Contact customers registered with our Priority Services Register to make sure they have the support they need while the power is off
- Deliver letters to all affected customers so they know the date and time their power will be turned off
This approach allows us to carry out repairs safely, with as little disruption as possible.
This is what the letter looks like:
If we’ve installed fault‑finding equipment, it will stay in place for a short amount of time. This allows us to keep monitoring the network and ensure there are no further issues.
Power cuts can happen for many reasons, including weather conditions, general wear and tear, or damage to the network. When we find a fault, we always work to repair it, however, there are some situations where the issue may temporarily resolve itself.
In most cases, an underground cable fault will only occur again if water or dirt finds its’ way into the cable. It may take a while for this to occur and it may occur occasionally, which can make it seem as if it was previously resolved even though the underlying issue still exists.
Overhead lines are exposed to the elements, such as weather, trees, third‑party damage, and objects coming into contact with them. To keep customers safe, equipment is installed on the network that automatically switches the power off if it detects a problem. This could happen if:
- Strong winds cause the line to move or pull against the electricity pole
- Tall vehicles or machinery come into contact with overhead lines
- Trees or branches touch or fall onto the line
In most cases, your power cuts will have stopped because we’ve repaired the problem. This may be through a permanent repair or by temporarily rerouting the electricity supply while further work is carried out.
We understand that an unexpected power cut can be disruptive, affecting your day‑to‑day routine, medical equipment, your business, or working from home. The tips below may help make things easier if it happens again.
Staying safe and comfortable
- Keep warm and use safe lighting such as torches rather than candles.
- Avoid moving around in the dark where possible.
- Switch off appliances and equipment to help prevent damage when the power returns.
Fridge and freezer
- Most fridges and freezers will maintain their temperature for up to 12 hours if the doors remain closed.
- Always check the manufacturer’s guidance for specific advice.
Staying in touch
- Use a charged mobile phone to receive updates.
- Call 105 if you need help, information, or reassurance during a power cut.
Restarting equipment
- Wait until power is fully restored before switching appliances back on to help prevent faults or damage.
Are you a Priority Services customer?
Medical or care needs
- If you rely on medical or care equipment, check that battery back‑up is available.
- Let us know if you need additional support during a power cut.
Extra support
- If you’re struggling to cope, please tell us, we can provide welfare support and practical advice.
- Customers registered on the Priority Services Register can receive extra support and regular updates during power cuts.
Do you have a business?
Business continuity
- Follow your emergency or business continuity plan so staff know what to do. This may include adjusted opening hours, use manual processes, or temporarily relocating activity.
- If you don’t yet have a plan, consider putting one in place for the future.
Alarms and systems
- Some alarms or security systems may activate or reset after a power cut. Contact your supplier if needed.
Are you working from home?
Protect your work
- Use auto‑save where possible to reduce the risk of losing work during an unexpected outage.
Use battery power wisely
- Switch to a laptop or mobile device and reduce screen brightness to help batteries last longer.
Keep others informed
- If the power cut affects your ability to work, let your employer or colleagues know as soon as possible so plans can be adjusted, for example, flexible hours or offline tasks.
