Electrical wiring doesn't last forever. Most UK homes built before the 1990s are running on wiring that's approaching — or has already passed — the end of its safe working life. The problem is that wiring hides behind walls, under floors, and above ceilings, so you can't just look at it and know whether it's safe.
What you can do is watch for warning signs. The seven signs below are the ones qualified electricians encounter most often when called to properties with dangerous wiring. If you recognise even one of these in your home, it's worth getting a professional inspection. If you recognise several, treat it as urgent.
1. Frequently Tripping Circuit Breakers
Every modern consumer unit (fuse board) has miniature circuit breakers (MCBs) and a residual current device (RCD). These are safety devices — they trip to cut the power when they detect a fault. An occasional trip is normal. If your toaster and kettle are on the same circuit and you run both at once, the MCB might trip because the circuit is momentarily overloaded.
Frequent tripping is a different matter entirely. If the same breaker trips repeatedly, or your RCD cuts out every few days, something is wrong. The most common causes are:
- Deteriorating cable insulation — old cables with cracked or degraded insulation allow current to leak to earth, triggering the RCD.
- Overloaded circuits — older homes were wired for far fewer appliances than modern households use. A ring main designed in the 1970s wasn't built to handle a dishwasher, washing machine, tumble dryer, and microwave simultaneously.
- Loose connections — wiring connections can work loose over decades, creating intermittent faults that trip breakers unpredictably.
If your breakers trip more than once or twice a month, call a qualified electrician for an Electrical Installation Condition Report (EICR). Don't just keep resetting the breaker — it's tripping for a reason.
2. Flickering or Dimming Lights
A single flickering bulb is usually just a loose bulb or a failing LED driver — swap the bulb first and see if it stops. But if multiple lights flicker across different rooms, or lights dim noticeably when you switch on a high-draw appliance like a washing machine, the problem is almost certainly in the wiring rather than the bulbs.
Flickering across multiple circuits typically points to a problem at the main supply or within the consumer unit itself — loose busbar connections, corroded terminals, or deteriorating main tails. Dimming when appliances kick in usually means circuits are overloaded or the main supply cable is undersized for the property's current demand.
Neither issue is something to ignore. Loose connections generate heat, and heat in electrical connections is how fires start.
3. Burning Smell or Discoloured Sockets
This one is urgent. If you can smell burning plastic, hot metal, or a fishy odour near sockets or switches, switch off the power at the consumer unit and call an electrician immediately. Do not wait.
A burning smell means something is overheating. The most common causes are arcing at a loose connection, an overloaded socket, or insulation that has broken down and is allowing a short circuit. Brown or black scorch marks around socket faceplates are visible evidence that overheating has already occurred.
Electrical fires in UK homes cause around 14,000 call-outs for fire and rescue services each year, according to Electrical Safety First. Many of these start behind walls, in the exact spots homeowners can't see. A burning smell or discoloured socket is your early warning — take it seriously.
4. Warm or Buzzing Sockets and Switches
Touch the faceplate of your sockets and light switches occasionally. They should be cool to the touch. If a socket feels warm — not just slightly from a plugged-in appliance, but noticeably warm even when nothing is plugged in — there's excessive resistance in the wiring behind it.
Resistance in electrical connections generates heat. Common causes include:
- Loose terminal screws inside the socket or switch
- Corroded copper connections
- Backstab connections (push-fit terminals) that have worked loose over time
- Cables that are undersized for the load they're carrying
Buzzing from a socket or switch is another red flag. A faint hum from a dimmer switch is normal, but audible buzzing from a standard socket or light switch indicates arcing — electrical current jumping across a gap in a loose or damaged connection. Arcing is one of the primary causes of electrical fires.
5. Your Wiring Is More Than 25–30 Years Old
The Institution of Engineering and Technology (IET) recommends that domestic electrical installations are inspected at least every 10 years, and the expected lifespan of a properly installed wiring system is around 25–30 years. If your home was wired (or last rewired) before the mid-1990s, the cables are likely reaching the end of their intended service life.
Older properties present specific risks:
- 1960s–1970s properties may contain aluminium wiring, which oxidises at connections and creates high-resistance joints that overheat. Some properties from this era also used rubber-insulated cables which become brittle and crack with age.
- 1950s and earlier properties may still have lead-sheathed or vulcanised rubber cables — both are well past their safe lifespan and should be replaced immediately if found.
- 1980s properties often used early PVC-insulated cables that, while better than rubber, may not meet current standards for fire resistance or energy efficiency.
If you're not sure how old your wiring is, look for clues: round-pin sockets, black cables (modern cables are grey or white), fabric-covered flex at light fittings, or a wooden-backed fuse board. Any of these suggest wiring that's well overdue for replacement.
6. You Have a Fuse Box with Rewirable Fuses Rather Than MCBs
If your home still has an old-fashioned fuse box with rewirable fuses — the type with a thin piece of fuse wire stretched between two screws — your electrical installation predates modern safety standards. Rewirable fuses were common until the 1980s and are still found in many UK homes today.
The problem with rewirable fuses is that they're imprecise. They'll eventually blow if there's a serious overload, but they don't offer the same level of protection as modern MCBs and RCDs. Critically, they can't detect earth leakage faults at all — that's what an RCD does, and old fuse boxes don't have one. An RCD can detect a fault and cut the power in 40 milliseconds, potentially saving a life. A rewirable fuse might let a dangerous fault persist for much longer.
Upgrading from an old fuse box to a modern consumer unit with MCBs and dual RCD protection typically costs between £350 and £600, depending on the number of circuits. It's one of the most cost-effective safety upgrades you can make to an older property. Most electricians can complete the upgrade in a single day.
7. You're Adding High-Demand Circuits
This isn't strictly a sign of faulty wiring — it's a sign that your existing wiring may not cope with increased electrical demand. Modern additions to UK homes frequently require significant electrical capacity:
- EV charger (7kW) — needs a dedicated 32A circuit from the consumer unit, plus earthing arrangements that meet the latest BS 7671 regulations.
- Hot tub (13–32A) — requires a dedicated circuit with RCD protection, often with heavier cabling than a typical domestic circuit provides.
- Kitchen extension — a modern kitchen with induction hob, double oven, dishwasher, and multiple socket outlets can easily draw 40–60A across its circuits.
If your home's existing wiring is already near capacity — especially in older properties with a 60A or 80A main fuse — adding these loads without upgrading the wiring could trip your main supply fuse or, worse, cause cables to overheat. A qualified electrician will carry out a maximum demand assessment to determine whether your existing installation can handle the additional load, or whether a partial or full rewire is needed first.
How Much Does Rewiring Cost?
Rewiring costs vary significantly by property size, age, and location, but here are typical 2026 prices for UK homes:
- 1-bed flat: £2,500 – £3,500
- 2-bed terrace: £3,500 – £5,000
- 3-bed semi-detached: £5,000 – £7,000
- 4-bed detached: £7,000 – £10,000
These prices include labour, materials, a new consumer unit, and the Electrical Installation Certificate you'll receive on completion. They don't usually include redecorating after the work — chasing cables into walls leaves marks that need filling and painting. Budget an additional 10–20% for making good and redecorating.
For a more detailed breakdown, see our domestic rewiring service page.
What to Do If You Recognise These Signs
If any of these warning signs sound familiar, here's what to do — and what not to do.
Don't Attempt DIY Electrical Work
Electrical work in England and Wales is governed by Building Regulations Part P. Most work beyond changing a light fitting or replacing a socket faceplate must be carried out by a qualified electrician or notified to your local building control. DIY electrical work is not only dangerous — it can invalidate your home insurance and create serious problems when you come to sell the property.
Get an EICR (Electrical Installation Condition Report)
An EICR is a formal inspection of your home's electrical installation by a qualified electrician. They'll test every circuit, check the condition of cables, connections, and protective devices, and issue a report grading any defects found. An EICR for a typical 3-bed house costs between £150 and £300 and takes 2–4 hours.
Choose a Part P Registered Electrician
Always use an electrician registered with an approved competent person scheme: NICEIC, NAPIT, ELECSA, or STROMA. Registration means they're qualified, insured, and their work is regularly assessed. They'll provide proper certification and notify building control on your behalf.
Read our guide on how to choose a qualified electrician for a complete checklist of what to look for before hiring.
If you're unsure whether your home needs rewiring, the best first step is an EICR. It gives you a clear, professional assessment of your wiring's condition — and peace of mind if everything turns out to be fine.