Your house probably needs rewiring if it still has rubber, lead-sheathed or fabric-covered cables, an old fuse box with rewireable fuses, no earth on the lighting circuits, or signs of overheating such as scorch marks and warm sockets. Wiring that is simply old is not automatically unsafe, though, so the only reliable way to decide is to have the installation inspected and tested.
Below we go through the most common warning signs we see in London homes, what a rewire typically costs, and how to find out for certain whether you need one.
10 signs your house may need rewiring
1. Rubber-insulated or fabric-covered cables
Cables insulated with vulcanised rubber were common until around the 1960s. Over time the rubber dries out, cracks and crumbles, leaving bare conductors inside walls and ceilings. If you see black, brittle cable at the back of a light fitting or in the loft, it is a strong sign a rewire is due.
2. Lead-sheathed cables
Some older properties, particularly Victorian and Edwardian houses across London, still have lead-sheathed wiring. The sheath was sometimes used as the earth path, which is unreliable, and the insulation inside is usually rubber. It is long past its expected life.
3. An old fuse box
A wooden-backed board, a cast-iron switch or a fuse box with rewireable fuses (the type you repair with fuse wire) suggests the installation hasn't been significantly updated in many years. On its own that might mean a consumer unit replacement rather than a full rewire, but it often goes hand in hand with older cabling.
4. No RCD protection
Residual current devices cut the power quickly if current leaks to earth, for example through a person. Homes without them lack an important layer of protection against electric shock. Adding RCD protection to very old wiring can also reveal faults, because it is much more sensitive than old fuses.
5. No earth on lighting circuits
Many older lighting circuits were installed without a circuit protective conductor (earth). That might not matter with plastic fittings, but it makes metal light fittings and switches potentially dangerous.
6. Scorch marks, warm sockets or a burning smell
Discolouration around sockets and switches, plugs that feel hot, or a fishy or burning smell are signs of overheating. Stop using the affected outlet and get it checked. If you smell burning and cannot find the cause, switch off at the main switch and call an emergency electrician.
7. Frequent tripping or blown fuses
Occasional trips happen, but regular tripping can mean overloaded circuits, deteriorating insulation or a fault that keeps recurring. Our guide on what to do when your RCD keeps tripping explains how to narrow it down safely.
8. Flickering or dimming lights
Lights that flicker when appliances switch on can indicate loose connections or circuits that are struggling with modern loads. It is worth investigating rather than ignoring.
9. Too few sockets and lots of extension leads
Homes wired decades ago weren't designed for today's appliances, chargers and home offices. Relying on chains of extension leads and adaptors increases the risk of overheating and is a sign the installation no longer fits how you live.
10. Old round-pin sockets or light switches on skirting boards
Round-pin sockets, round toggle switches and sockets mounted in skirting boards are telltale signs of very old installations. If you see them, assume the wiring behind them is of a similar age.
The definitive answer: an EICR
Visual signs are useful, but they can't tell you the condition of cables buried in walls. An Electrical Installation Condition Report (EICR) involves testing insulation resistance, earth continuity, polarity and the operation of protective devices across the installation. The report then records any defects using observation codes, from C1 (danger present) to C3 (improvement recommended).
An EICR will tell you whether you need a full rewire, a partial rewire or just a few targeted repairs. Sometimes older-looking wiring tests perfectly well; sometimes a fairly modern-looking installation has serious faults. Our EICRs start from £79 for a studio flat up to £149 for a four-bed house, and you receive a digital certificate the same day with photos, observations and a remedial cost breakdown. For more on how the codes work, read EICR codes explained.
How much does a rewire cost in London?
We don't publish fixed rewire prices because every property is different. The figures below are typical market ranges for London and the Home Counties, and are a guide only:
| Property | Typical market range |
|---|---|
| One-bed flat | £3,000 – £5,000 |
| Two to three-bed house | £5,000 – £9,000 |
| Four-bed house or larger | £9,000+ |
The main factors are the size of the property, the number of sockets and lights you want, whether the home is occupied or empty, floor and wall construction, access in period properties, and whether you add extras such as data cabling, outdoor circuits or an EV charger supply. Plastering and redecoration are often priced separately, so check what your quote includes.
Full rewire or partial rewire?
A full rewire replaces all fixed wiring, accessories and usually the consumer unit. A partial rewire replaces only the circuits that are in poor condition, for example the lighting circuits in an older house where sockets were rewired more recently. A good electrician will recommend the option that suits the condition of your installation, not the one that earns the most.
Rewiring and Part P
A rewire is notifiable work under Part P of the Building Regulations. Using an NICEIC registered contractor means the work is self-certified and building control is notified for you. You receive an Electrical Installation Certificate and a Building Regulations compliance certificate, both of which are important when you sell the property. If you are buying or selling, see our guide to EICRs when buying or selling a house.
Landlords and older wiring
If you let a property, the Electrical Safety Standards in the Private Rented Sector (England) Regulations 2020 require the installation to be inspected and tested at least every five years. Old wiring that is found to be potentially dangerous must be put right within 28 days, or sooner if the report says so. Planning a rewire between tenancies is usually far less disruptive than reacting to an unsatisfactory report mid-let.
Find out whether you need a rewire
If you've noticed any of the signs above, the first step is an inspection. Polarity Electrics' NICEIC-certified engineers cover all of London and the Home Counties, with same-day and next-day appointments available. If a rewire is needed, we will give you a fixed written quote. Call 0203 908 4790 or book online. You can also find out more on our rewiring London page.
Frequently asked questions
How do I know if my house needs rewiring?
Warning signs include rubber, lead or fabric-covered cables, an old fuse box with rewireable fuses, scorch marks or warm sockets, no earth connection on lighting circuits and frequent tripping. The only reliable way to know is an Electrical Installation Condition Report (EICR) carried out by a qualified electrician.
How much does a rewire cost in London?
As typical market ranges, a full rewire of a one-bed flat in London often costs around £3,000 to £5,000, and a two to three-bed house around £5,000 to £9,000, with larger homes costing more. We give a fixed written quote after surveying the property.
How long does wiring last?
Modern PVC-insulated cables can last for decades if they are not damaged or overloaded, but rubber-insulated wiring from before the 1960s has usually deteriorated badly. Age alone is not the deciding factor; condition, as found by testing, is what matters.
Can I live in my house during a rewire?
It is possible in some cases, especially if the work is phased room by room, but it is disruptive because floors and walls are opened up and power is off for periods. Many people move out for the first-fix stage, particularly in smaller homes.