What is this?
A burning plastic smell from electrical fittings is a sign that insulation on wiring, the plastic casing of a socket or switch, or the internal components of an appliance are overheating and melting. Electrical cable insulation is made from PVC or similar thermoplastics, and when it overheats, it produces a distinctive sharp, acrid smell. This is a clear indication that something is seriously wrong and immediate action is needed.
Common causes
- Overheating wiring connections causing PVC cable insulation to melt
- Socket or switch plastic casing overheating due to internal arcing
- Faulty appliance with melting internal components
- Overloaded extension lead or adaptor overheating
- Light fitting ballast or driver overheating
- Cable damaged during building work now carrying current through compromised insulation
Is it dangerous?
This is an emergency. Melting plastic insulation means temperatures have exceeded 70 degrees Celsius (the rated temperature for PVC cable) and are likely much higher. At these temperatures, there is a real and immediate fire risk. The fumes from burning PVC are also toxic, containing hydrogen chloride gas. Take immediate action to identify and isolate the source.
Can I fix it myself?
No. Try to identify where the smell is coming from — sniff around sockets, switches, the consumer unit, and appliances. If you can identify a specific socket or fitting, turn off the circuit at the consumer unit. If you cannot locate the source, turn off the main switch. Ventilate the area by opening windows. Call an emergency electrician.
When to call an electrician
Call an emergency electrician immediately. A burning plastic smell from electrics is never trivial. If you can see smoke, melted plastic, or flames, call 999 first. Do not delay — electrical fires can spread rapidly through cable routes in walls and ceilings.
What will an electrician do?
Locate the source of the overheating using thermal imaging and systematic testing
Isolate the affected circuit and inspect all connections
Replace any damaged sockets, switches, or fittings with melted or charred components
Inspect and replace any cable with damaged insulation
Test the circuit insulation resistance to ensure no further damage exists
Investigate the root cause — loose connection, overload, or cable damage — and fix it
Typical cost
£100 – £350
Emergency callout rates typically apply. Costs depend on the extent of damage — replacing a single melted socket is cheaper than replacing damaged cable runs.
