Most electrical niggles can wait for a routine visit - a dead socket here, a flickering bulb there. But a handful of faults are your home's early-warning system for a fire or a shock, and they need acting on the moment you notice them. Electrical fires often start inside walls or sockets where you can't see them, so by the time you smell or feel something, the problem is already well advanced. Here are the seven signs that mean stop, isolate, and call.
If you smell burning or see scorching, switch the affected circuit - or the whole supply - off at the consumer unit and stop using it until an electrician has checked it. No repair is worth a fire.
The 7 Signs That Can't Wait
Each of these points to heat, arcing, or a breakdown of insulation somewhere in your wiring. Individually they're warnings; together they're an emergency.
- 1. A burning or fishy smell
- Overheating plastic gives off a sharp, fishy odour. If you can smell it near a socket, switch or the fuse board, there's heat where there shouldn't be - isolate it now.
- 2. Scorch marks or browning
- Discolouration or black marks around a socket or plug mean arcing or overheating has already happened. Stop using that point immediately.
- 3. Warm or hot sockets and switches
- Accessories should never feel warm. Heat means a loose connection or an overloaded circuit quietly cooking behind the faceplate.
- 4. A board that keeps tripping
- One trip is a fault doing its job. A breaker that won't stay on, or trips the instant you reset it, is telling you something is genuinely unsafe.
- 5. Buzzing or crackling
- Electricity should be silent. A buzz or crackle from a socket, switch or the consumer unit is the sound of arcing - a serious fire risk.
- 6. Flickering or dimming lights
- If lights dim across the house when an appliance kicks in, or flicker for no reason, the supply or a main connection may be struggling.
- 7. Any shock or tingle
- A tingle from a tap, appliance or switch means current is finding a path it shouldn't. This is a direct shock risk and always an emergency.
What's Actually Going On
Nearly all of these come down to one of two things: a loose connection, or insulation breaking down. A loose terminal behind a socket creates resistance, resistance creates heat, and heat chars the surrounding plastic and cable until it arcs or ignites. Breakdown of the insulation around a cable lets current leak to earth or across conductors - which is what trips your RCD and what gives you a shock. Neither gets better on its own, and both get worse with use.
What to Do the Moment You Notice
Switch off the affected circuit at the consumer unit. If you smell burning and can't tell which circuit, switch off the main switch.
A single faulty appliance is a very common cause. Unplug everything on that circuit before you reset anything.
Never remove a socket faceplate or open the consumer unit. This is notifiable Part P work for a registered electrician.
What an Emergency Electrician Will Do
When the electrician arrives, the first job is always to make it safe - isolate the fault and confirm nothing is live that shouldn't be. From there they'll trace the cause, repair or replace the faulty part, and test the circuit before signing it off.
- Make the installation safe and confirm what's affected
- Trace the fault with test equipment rather than guesswork
- Replace the failed socket, cable section or breaker
- Test and issue the right certificate for notifiable work
What It's Likely to Cost
An emergency call-out is usually £75-£120 in the day and £120-£180 out of hours, with most make-safe jobs done in the first hour. A full consumer-unit replacement is the bigger-ticket item at £450-£900. Our emergency electrician cost guide breaks down every common job and what pushes the price up.
How to Stop It Happening Again
- Don't daisy-chain extension leads or overload sockets
- Replace any socket or plug that's cracked, loose or browning
- Have an EICR safety inspection every 10 years (5 for a rental)
- Fit RCD protection if your board doesn't already have it
If your power has gone out rather than something smelling hot, work through our what to do in a power cut guide first - it's often a single tripped appliance. And if you've spotted any of the seven signs above, don't sit on it: get an emergency electrician on the way out to you, day or night.