If your extension lead is not working, it can prevent appliances from receiving power and may indicate a fault within the lead, plug, or socket. This guide explains the most common causes, safe checks you can carry out, and when the issue should be investigated by a qualified electrician.
If you’re unsure where the fault is, using a simple Socket tester can quickly help identify whether the issue is with the socket, appliance, or wiring.
Common Reasons an Extension Lead Is Not Working
An extension lead may stop working due to internal faults or issues with the power supply.
Common causes include:
- Faulty or blown fuse inside the plug
- Damaged or broken cable
- Loose internal wiring
- Worn or faulty extension lead sockets
- Fault with the wall socket supplying power
- Overloaded extension lead causing failure
Safe Checks You Can Carry Out
Some simple checks can help identify the cause of the problem.
- Check the wall socket is working by plugging in another device
- Inspect the extension lead for visible damage
- Check and replace the fuse in the plug if needed
- Try plugging the extension lead into a different socket
- Avoid overloading the extension lead with too many appliances
- Use a Socket tester to quickly confirm whether the socket is wired correctly — this can immediately rule out common faults without needing to remove the socket.
If the extension lead still does not work, it should be replaced.
If you’re comfortable carrying out basic checks, using a simple tester can help quickly identify whether the fault is with the socket, appliance, or wiring.
Before calling an electrician, many common electrical faults can be quickly identified using a few simple tools at home. These are the same types of testers electricians use to diagnose problems safely.
Recommended Tools
If you’re confident carrying out basic checks, these tools can help identify electrical faults safely:
- Socket tester – quickly shows if the socket is wired correctly and safe to use
- Multimeter – helps check voltage, continuity, and identify faults
- Voltage tester pen – detects live wires instantly without contact
- Surge protected extension lead – provides safer power distribution and helps protect appliances from electrical faults and overloads
- Spare fuse kit – allows you to safely replace blown fuses in plugs when appliances stop working
For a full list of tools you can use, see our guide on best electrical tools for homeowners.
Using these tools can help you identify the problem in minutes and avoid unnecessary call-out costs.
Many homeowners use a simple socket tester first before deciding whether an electrician is needed.
These tools are widely available online and can be useful for basic fault finding in the home.
When to Call an Electrician
Contact a qualified electrician if:
- Multiple sockets in your home are not working
- The circuit breaker has tripped and will not reset
- There are signs of burning or overheating
- You are unsure whether the issue is with the wiring
Electrical faults should always be investigated safely.
Need an Electrician?
If this issue keeps happening or you’re unsure what’s causing it, a qualified electrician can safely diagnose and fix the problem. Electrical faults can worsen over time, so it’s best to get professional advice rather than risk damage or injury.
UK Electrical Safety Advice
Electrical faults can be dangerous. If you are unsure, always seek advice from a qualified electrician. This guidance is for general information only and does not replace a professional inspection.
For general guidance on household electrics, see our electrical advice for UK homes.
Related Electrical Problems
You can view other electrical faults on our Common Electrical Problems (UK) page.