What is this?
A burning smell from the consumer unit (fuse box) is extremely serious. The consumer unit is the central distribution point for all your home's electricity, carrying the full load of the property. Overheating here means a connection is failing under the full electrical demand of the house. Consumer unit fires are a significant cause of domestic electrical fires in the UK, which is why BS 7671 now requires all new consumer units to be metal-clad (non-combustible).
Common causes
- Loose busbar connections overheating under load
- Failing MCB or RCD with degraded internal contacts
- Corroded main switch connections
- Overloaded consumer unit carrying more current than designed for
- Poor workmanship from a previous installation — loose terminals, exposed conductors
- Old rewirable fuse carriers with incorrect fuse wire ratings
Is it dangerous?
This is an emergency. The consumer unit carries the highest currents in your home, and a fault here can escalate into a fire rapidly. If you smell burning from the consumer unit, turn off the main switch immediately if it is safe to do so. If the unit is visibly damaged, smoking, or you cannot safely reach it, evacuate and call 999. Do not touch the unit if you can see damage or melting.
Can I fix it myself?
No. If it is safe to do so, turn off the main switch at the consumer unit. If the unit is hot to the touch or smoking, do not touch it — evacuate and call 999 and then an emergency electrician. Do not attempt to open the consumer unit cover under any circumstances.
When to call an electrician
Call an emergency electrician immediately. If there is visible smoke, flames, or you cannot safely turn off the main switch, call 999 first, then call the electrician. This is one of the most serious domestic electrical faults.
What will an electrician do?
Safely isolate the supply (may need to contact the DNO to pull the main fuse)
Open the consumer unit and inspect all connections for overheating damage
Identify the source of the burning — loose terminal, failing device, or cable issue
Replace any damaged MCBs, RCDs, or the entire consumer unit if compromised
Torque-test all connections to the correct specifications
Issue a Minor Works Certificate or Electrical Installation Certificate as appropriate
Typical cost
£150 – £650
If the consumer unit is repairable, costs are at the lower end. If a full consumer unit replacement is needed (common with older or damaged units), expect £350–£650 including certification.
