Burning smell from the fuse box

Do this first

A burning smell at the consumer unit (the fuse box, where your circuit breakers or fuses live) is one of the few electrical problems that cannot wait until morning.

1. If you see smoke, flames or glowing, get everyone out, close the door behind you and call 999. Do not go back for anything.
2. If there is only a smell, and the area is dry and you can reach it without touching anything hot, switch off the main switch on the consumer unit. It is usually the large switch at one end, often marked “main switch” or “isolator”.
3. Do not take any covers off. Do not touch the meter or the black sealed box beside it.
4. Unplug heavy appliances if you can do it safely, so they do not restart when power returns.
5. Get an electrician to look before anything is switched back on. Our burning smell, sparking or hot sockets page covers how that visit runs.

If someone has had a shock, do not touch them while they may still be in contact with the supply. NHS inform advises switching off at the mains or meter point if possible, then phoning 999.

Whose equipment is it?

Under the stairs or in a meter cupboard you will usually find three separate things. Who you call depends on which one the smell is coming from.

Part	What it looks like	Who owns it	Who to call
Cutout (service head)	Black or grey sealed box where the street cable comes in, with the main fuse inside	Network operator (UK Power Networks across Bromley)	105 or 0800 31 63 105
Meter	The box with the display or dials	Your energy supplier or their meter operator	Your supplier, or 105 if it is an emergency
Meter tails	Two thick cables from the meter to your consumer unit	Usually the property owner	An electrician
Consumer unit and circuits	The box with switches or fuses, and all wiring after it	The property owner	An electrician

If the smell or heat is at the cutout or meter, you cannot switch that off yourself, because it is before your main switch. Call 105. UK Power Networks also asks people to call 0800 31 63 105 to report anything dangerous on its equipment.

What causes it

The usual cause is heat at a connection that has worked loose. Copper and the screws holding it expand and shrink a little every time a heavy load runs. Over years, a terminal that was tight can loosen. A loose terminal runs hot, the plastic around it chars, and you smell it.

Common spots:

• Main switch or meter tail terminals. These carry the whole house load. A loose tail on a busy winter evening with heating, cooking and a shower running is a classic case.
• A breaker or fuse holder for a heavy circuit. Cooker, electric shower, immersion heater or an EV charger.
• Old rewireable fuse carriers. The ceramic holders with fuse wire in them can loosen in their sockets.
• A failing breaker. Breakers wear out and their internal contacts can overheat.

London Fire Brigade lists scorch marks and breakers that trip for no obvious reason among the signs of loose or dangerous wiring.

Why Bromley homes see this

Bromley has more detached houses than anywhere else in London we cover. The VOA Council Tax stock of properties 2025 puts 14.4% of Bromley homes as detached and 5.3% as bungalows, with 29.8% built between 1919 and 1939 and 26.6% between 1945 and 1972. Large houses in Chislehurst, Keston and Bickley, and the interwar semis of Petts Wood and West Wickham, often carry big loads: extensions with underfloor heating, garden offices on long cables, hot tubs, EV chargers. All of that current passes through the same meter tails and main switch.

When those homes have had a new kitchen or a garden building added over the years without the consumer unit being reviewed, the main connections can end up working harder than they were set up for. Read more about the borough on our Bromley page.

What the electrician will do

1. Confirm the supply is off and safe to work on. If the fault is at the cutout, they will tell you to call 105 and will not touch it.
2. Look for heat damage: browned plastic, melted insulation, discoloured copper, a breaker that feels hot.
3. Tighten or remake connections that are sound, and replace parts that are damaged.
4. Test the circuits before switching back on, so they know the heat was not caused by a fault further along.
5. Explain what they found. If the board itself is damaged or very old, they may recommend a new consumer unit.

A new consumer unit is notifiable building work under Approved Document P, so it must be done by someone registered with a competent person scheme, or notified to Bromley Council building control. Ask to see the electrician’s scheme registration and check it on the scheme’s register. Our consumer unit replacement page explains that job.

The price is confirmed after a look at the job. A remade terminal and a new board are very different pieces of work.

After the scare

Once the immediate fault is fixed, it is worth knowing what else might be weak. Electrical Safety First recommends owner occupiers have the installation inspected at least every 10 years. If the smell came from a socket rather than the board, see burning smell from a plug socket.