Fire Protection· Warning Signs· Reviewed October 2026
Why is my electrical panel showing a burning plastic smell when it's cold outside?
Quick answer
A burning plastic smell from your electrical panel in cold weather most commonly means insulation on wiring inside the consumer unit is overheating due to a loose connection or overloaded circuit. Cold temperatures can cause metal components to contract, worsening already loose terminals. Turn off your main switch immediately, do not use the panel, and call a registered electrician today. This is a fire risk and should never be ignored or left overnight.
🏠Homeowner view
If you can smell burning plastic coming from your electrical panel, also called a consumer unit or fuse box, take it seriously. This smell almost always means something inside is getting hotter than it should be, and that heat is breaking down the plastic insulation on the wires or components inside the unit.
Why does cold weather make it worse? When temperatures drop, the metal parts inside your panel contract slightly. If a screw terminal was already a little loose, that contraction can open the gap just enough to cause arcing. Arcing is when electricity jumps across a small gap, and it generates intense localised heat. That heat is what you are smelling.
What you should do right now:
1. Do not ignore the smell or assume it will go away on its own.
2. If the smell is strong, smoke is visible, or the panel feels warm to the touch, turn off your main switch and call 999 before calling an electrician.
3. If there is no smoke and the smell is faint, turn off the main switch as a precaution.
4. Do not open the consumer unit yourself. The internal components carry live voltages even when the main switch is off, and only a qualified electrician should work inside it.
5. Check whether the smell started after a period of heavy electrical use, such as running heaters, which can point to an overloaded circuit.
What an electrician will look for:
A registered electrician will open the unit safely, inspect every terminal for signs of heat damage, scorching or discolouration, check that all connections are torqued to the correct tightness, and carry out insulation resistance tests to confirm no wiring has been permanently damaged.
Common causes they will investigate include loose neutral or live terminals, a failing MCB or RCD that is running hot, undersized cables for the load they carry, or an old plastic consumer unit that has deteriorated with age.
Do not delay calling a professional. A burning smell from a consumer unit is one of the most reliable early warning signs of an electrical fire. Act today.