Electrical wiring doesn’t come with an expiry label, which makes it easy to ignore. But an outdated or poorly maintained electrical installation is one of the leading causes of house fires in the UK — responsible for around 20,000 fires per year according to the Electrical Safety Council. Knowing the signs that your wiring needs attention, and understanding what a rewire involves, could save both money and lives.
How Old Is Too Old?
There is no fixed legal lifespan for domestic wiring, but general guidance from the Institution of Engineering and Technology (IET) and BS 7671 (the Wiring Regulations) indicates:
- Rubber-insulated wiring: pre-1960s, insulation turns brittle and cracks — replace immediately
- Lead-sheathed wiring: pre-1950s, highly dangerous — replace immediately
- Aluminium wiring: 1960s–1970s, corrodes at connections — requires specialist inspection
- PVC-insulated wiring (1960s–1980s): may still be serviceable but inspect urgently
- Modern PVC/XLPE (post-1985): expect 25–40 years of serviceable life; inspect every 10 years
The IET recommends periodic inspection of domestic wiring every 10 years for owner-occupied homes and every 5 years for rental properties (or at change of tenancy).
Warning Signs to Look For
The Fuse Box (Consumer Unit)
The consumer unit is the best single indicator of wiring age and condition:
- Old-style ceramic or re-wireable fuses rather than modern MCBs (miniature circuit breakers): the installation is likely 40+ years old
- No RCD protection (residual current device — a device that trips in milliseconds if current leaks to earth): modern wiring requires RCDs on socket circuits and all circuits in bathrooms and kitchens under BS 7671 2018 (18th Edition)
- Overfused circuits: anyone can fit an incorrectly rated fuse in an old ceramic holder, creating a fire risk
Around the Home
| Warning Sign | What It Suggests |
|---|---|
| Black rubber insulation on cable ends (visible at sockets/switches) | Pre-1960s rubber wiring — needs urgent inspection |
| Round-pin sockets or old bakelite light switches | Pre-1967 installation |
| Scorching, burn marks or discolouration around sockets | Loose connections or overloaded circuits — immediate risk |
| Flickering lights (consistent, not bulb-related) | Loose connections in circuit |
| Sockets or switches feel warm to the touch | Overloaded circuit or failing connections |
| Burning or fishy smell from sockets or consumer unit | Arcing — turn off and call an electrician today |
| Frequently tripping MCBs or blown fuses | Circuits at or over capacity, or failing cable insulation |
| No earthing on metal light fittings or sockets | Missing earth continuity — shock risk |
| Extension lead chains and adaptor plugs throughout | Insufficient sockets for current usage — circuit overloading |
| Only two pins in older-style sockets | No earth — pre-1977 standard |
What an Electrical Inspection Reveals
An Electrical Installation Condition Report (EICR) — the formal inspection and test — is carried out by a qualified electrician (registered with NICEIC, NAPIT, or Elecsa). It tests every circuit for:
- Insulation resistance
- Earth continuity and bonding
- RCD tripping times
- Loop impedance (the ability of the fuse or MCB to operate in a fault)
- Visual inspection of all accessible components
The report grades observations:
- C1 (Danger present): immediate action required
- C2 (Potentially dangerous): urgent remedial action needed
- C3 (Improvement recommended): not dangerous but advisory
An EICR costs £150–£350 for a typical 3-bedroom house. Landlords in England are legally required to hold a valid EICR and provide it to tenants; the legal maximum interval is 5 years.
Do You Need a Full Rewire or Just Remedial Work?
Not every old installation needs a complete rewire. The decision depends on the EICR findings:
- Consumer unit upgrade only: if circuits are sound but the fuse board lacks RCD protection, a new consumer unit installation (£600–£1,200) may be all that’s needed.
- Partial rewire: if specific areas (kitchen, bathroom, extension) have dangerous wiring but the rest of the house passes, those circuits alone may be rewired.
- Full rewire: if wiring is rubber-insulated, aluminium, or lead-sheathed throughout, or if there are pervasive C1/C2 observations across multiple circuits, a full rewire is the appropriate response.
Signs pointing to full rewire:
- Rubber or lead insulation anywhere in the installation
- No earth on any circuit
- Widespread C1/C2 observations in EICR
- Major renovation (kitchen, loft conversion, extension) that requires re-routing most circuits anyway
- Property built before 1970 that has never been rewired
What a Rewire Involves
A full rewire means replacing every circuit from the consumer unit outward — all cables, socket and switch faceplates, junction boxes, and the consumer unit itself. For an occupied home, it typically requires:
- An electrician chases cable runs into walls (or surface mounts in conduit)
- First fix: all cables installed, consumer unit replaced
- Plastering over chased runs (usually a separate trade, or the homeowner’s responsibility)
- Second fix: sockets, switches, and light fittings connected
- Testing and certification — an EICR is issued on completion
The work must be signed off by a Part P registered electrician, who self-certifies the notifiable work with Building Control. You receive a BS 7671 Electrical Installation Certificate on completion.
Cost of a Rewire
| Property | Full Rewire Cost (all-in, 2026) |
|---|---|
| 1-bedroom flat | £2,500–£4,500 |
| 2-bedroom house | £3,500–£5,500 |
| 3-bedroom semi | £4,500–£7,000 |
| 4-bedroom detached | £6,000–£10,000 |
| 5+ bedrooms, complex property | £9,000–£18,000+ |
Costs vary significantly by:
- Whether it’s occupied (harder access)
- How much plasterwork is needed after chasing
- Whether consumer unit upgrade is included
- Number of circuits and special circuits (kitchen ring, EV charger, outbuildings)
Add £1,500–£3,000 if you’re simultaneously installing new sockets throughout (going from 1 double per room to 3–4) or adding USB, smart, or outdoor sockets.
After the Rewire
A newly rewired house with a modern 18th Edition consumer unit will have:
- Full RCD protection (split-load board at minimum, RCBO per circuit on quality installs)
- Correct circuit sizing (T&E cable rated for the load)
- Surge protection device (now required by 18th Edition for new consumer unit installations)
- An EIC (Electrical Installation Certificate) for insurance and mortgage purposes
Keep the EIC safely — it’s often requested when selling the property.
