Short answer
Switch off the circuit concerned, pull out the plug and leave it off. A scorching smell or a warm socket is almost always caused by a bad connection, and that gets worse by itself. If you smell it in the meter cupboard, switch off the main switch and call straight away. Do not wait until tomorrow.
Who this article is for For the moment you smell or feel something that is not right. Read this first, then call.
What to do straight away
- Pull out the plug of whatever is connected, if that can be done safely.
- Switch off the circuit in the meter cupboard.
- If you smell it in the meter cupboard itself, switch off the main switch.
- Leave it off and do not switch anything back on to see whether it happens again.
- Call.
Do not put water on anything electrical. If there is visible fire, call 112 and only use an extinguisher that is suitable for it.
Why heat is the problem
Electricity creates heat where the resistance is high. In a good connection that resistance is virtually zero. If a contact deteriorates, through a weakened spring, a loose screw or oxidation, heat builds up at exactly that point.
That heat makes the contact worse still, so it gets even hotter. It is a process that speeds itself up, and that is why you do not wait with this. From the first discolouration to smouldering is often only a few weeks.
The places where it happens
| Place | What is usually going on |
|---|---|
| Dryer or oven socket | weakened contact springs from heavy loads |
| Junction box | push-in terminal from an old installation |
| Consumer unit | screw terminal that was never re-tightened |
| Extension lead or power strip | too heavy a load, coiled-up lead |
| Grid operator's service head | old terminal, work for the grid operator |
Four places where a bad connection gets hot.
What you can see yourself
- discolouration from white to yellow or brown around a socket opening
- a deformed or slightly melted plug
- soot marks or a black edge
- a ticking sound or sparks when plugging in
Take a photo of it before you pull out the plug, that helps with the assessment.
What I do when I come
I measure and look with a thermal imaging camera under load. That shows straight away which terminals are getting hot, even where nothing is visible to the eye yet. At a burnt point I do not just replace that one part but also check the rest of the same circuit, because the same terminals are just as old.
With old installations with push-in terminals or cloth-covered wiring, this is often the moment to look further. What to look out for is in recognising an old installation.
From my own work
A customer in Schinnen called about a faint smell of burning in the utility room. The dryer socket felt warm and was slightly yellowed. In the socket the spring contact had weakened, so the plug no longer sat tight. That creates resistance and therefore heat. A few more weeks and it would have become a smouldering fire behind a skirting board.
When to call an electrician
- There is a scorching or burning smell, even if it fades again
- A socket, switch or plug is warm or discoloured
- You hear ticking or see sparks when plugging in
This is a fault that takes priority. Call +31 43 204 18 26 during the day and outside office hours through the fault service.
Frequently asked questions
Can I wait until tomorrow?
No. A bad connection gets hotter by itself, and from the first discolouration to smouldering is often only a few weeks.
What do I do if there is already smoke?
Circuit or main switch off, and if there is visible fire, call 112. Do not use water on anything electrical.
Why do you replace more than that one part straight away?
Because the terminals in the same box are just as old and have been just as hot. Replacing only the burnt point does not solve the cause.
Further reading
RCD keeps tripping: how to find the cause yourself
Usually it is one appliance and not your installation. In four steps you find out yourself which one, and you read exactly where it stops and you need to call.
Lights flickering or dimming: what it tells you
Flickering in one light is usually the bulb or the dimmer. Flickering throughout the house is a reason to measure.
The circuit breaker trips: overload or short circuit
A breaker that only trips after a while points to overload. If it trips straight away, it is a short circuit.
Questions and comments
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