Signs your home needs rewiring (and what it costs in London)

Rewiring is the job homeowners put off longest, partly because of the cost and partly because it is hard to know whether you actually need it. Wiring is hidden, it fails gradually, and a house with serious electrical problems can look completely normal from the outside.

The good news is that wiring usually gives you warnings before it becomes dangerous, and there is a cheap, reliable way to find out where you stand before committing to anything. This guide covers the warning signs we look for, how to check the age of your installation yourself, what a rewire costs in London in 2026, and how to survive the work with your sanity intact.

The warning signs

No single item on this list proves you need a rewire, but the more of them you recognise, the more urgent a proper inspection becomes. The first few are things you can notice day to day; the rest are things to look for around the house.

• Frequent tripping. Breakers or RCDs that trip regularly without an obvious culprit often point to deteriorating insulation somewhere in the wiring.
• Buzzing sockets or switches. Healthy accessories are silent. Buzzing or crackling means a loose or failing connection.
• Discoloured or hot outlets. Brown marks around sockets, or faceplates that feel warm, mean heat is being generated where it should not be.
• A burning smell you cannot trace, especially a fishy or acrid plastic smell near sockets or the fuse board.
• Flickering lights, particularly when appliances switch on, beyond the brief dip a heavy load can cause.
• Old rubber or fabric insulated cable. Both were common before the 1960s, and the insulation becomes brittle and crumbles, leaving live conductors exposed.
• Round pin sockets, which indicate wiring from the 1950s or earlier that has never been replaced.
• A cast iron fuse board or one mounted on a wooden backboard, both signs of an installation that predates modern standards by decades.
• No RCD protection anywhere in the installation, leaving you without fast disconnection to protect against electric shock.

How to check the age of your wiring

You can learn a lot without lifting a floorboard. Start at the fuse board: a modern metal consumer unit with RCDs suggests recent work, while a plastic board without RCDs or a rewirable fuse box points to wiring that is decades old. Look at the cable where it enters the board. Grey or white PVC flat cable is the modern standard; black rubber, lead sheathing or fabric braiding means original mid century wiring.

Check a couple of sockets and switches too. Lift the cover of a light switch (with the circuit off) and look at the cable colours. Red and black conductors were used before 2006; brown and blue after. Red and black wiring is not automatically a problem, but combined with other signs it tells you the installation is at least twenty years old.

The definitive answer comes from an Electrical Installation Condition Report (EICR). An electrician tests every circuit, measures insulation resistance and earth continuity, and codes every defect found. It typically costs £150 to £250 in London and tells you precisely what state the installation is in.

Full rewire or partial rewire?

A full rewire replaces every cable, every accessory and the consumer unit. It is the right call when the wiring is uniformly old, when insulation resistance readings are poor across the board, or when you are doing major renovation work anyway and the walls are already open.

A partial rewire replaces the circuits that need it and keeps the ones that test well. It is common in houses that have been extended or partly modernised over the years, where a 1980s kitchen circuit might be fine while the original lighting circuits upstairs are rubber insulated relics. There is no shame in a partial rewire done for the right reasons, but be wary of anyone proposing one without test results to justify which circuits stay.

The EICR is what makes this decision honest. Without test data, choosing between full and partial is guesswork, and guesswork tends to be expensive in one direction or dangerous in the other.

What rewiring costs in London

For a full rewire in London in 2026, realistic budgets run from £4,000 to £8,000 depending on the size of the property and the level of finish. A two bed flat with standard white accessories sits at the lower end. A large house with a high socket count, designer switch plates, new lighting design and smart home provision pushes towards the top and sometimes beyond it.

Partial rewires start from around £1,800 for a couple of circuits, again depending on access and finish. Every full rewire should include a new consumer unit, full testing and an Electrical Installation Certificate, and the work is notifiable to building control. Making good the walls afterwards is usually priced separately, so check whether plastering is in your quote.

As with any building work in London, quotes vary widely. The cheap ones usually achieve their price by chasing fewer walls, reusing more old cable or skipping the making good. Get the scope itemised so you are comparing the same job.

How disruptive is it really?

Honestly: quite disruptive, but for a shorter time than most people fear. A full rewire on a two or three bed home typically takes five to ten working days. Floorboards come up, walls are chased, and there is dust despite everyone's best efforts. Carpets need lifting in most rooms, and furniture needs moving away from walls.

The disruption is very front loaded. The first stage, running the new cables, is the messy part. Second fix, when sockets and switches go on and circuits go live, is much calmer. Power is off in sections rather than the whole house for the whole job, and a good electrician will sequence the work so you keep a working kettle, fridge and a couple of sockets each evening.

Planning around the work

A few decisions made early make the whole job smoother and cheaper. Decide socket positions and lighting before work starts, because moving things once cables are run costs real money. If you are ever going to want an EV charger, an electric shower or a garden supply, say so now, because provision is cheap during a rewire and expensive after it.

• If the house is empty, rewire before you move in or decorate. It is the single biggest saving available.
• If you are living through it, clear one room at a time and agree the sequence with your electrician.
• Book the plasterer for immediately after first fix is inspected, not weeks later.
• Keep pets and children away from open floors, and expect some rooms to be out of action for a few days each.
• Ask for the certificate and building control notification before making the final payment.

Start with an EICR, not a quote

If you recognise several of the warning signs above, the sensible first step is not to collect rewiring quotes. It is to get an EICR. For a modest fixed cost you find out whether you need a full rewire, a partial one, or just some targeted remedial work, and you get test results that any electrician can quote against accurately.

We carry out EICRs and rewires across Greater London, and a fair share of the inspections we do end with us telling the owner they do not need a rewire yet. That is the point of testing first: you spend money on facts before you spend it on cable.