How much does a fuse box replacement cost in London? (2026 guide)

If you have been quoted anywhere from £300 to £1,500 for the same job, you are not alone. Fuse box replacement (the correct term is consumer unit replacement) is one of the most commonly mispriced jobs in domestic electrics, and the spread of quotes in London is wider than almost anywhere else in the country.

This guide sets out what we actually charge and see charged across Greater London in 2026, what makes the price move, and how to tell a proper quote from one that will cost you more in the long run. We fit consumer units across London every week, so these are working numbers, not guesses.

The typical London price range

For a straightforward consumer unit replacement in a London home, expect to pay between £550 and £900. That covers supply and installation of a modern metal consumer unit, full testing of your circuits, certification and labelling. Most three bed houses with a healthy installation land somewhere in the middle of that range.

Below £550 you should start asking questions. Above £900 there is usually a specific reason, such as a large number of circuits, remedial work on the existing wiring, or difficult access. A good electrician will tell you exactly which of those applies before you commit.

What pushes the price up

No two installations are the same, and a few factors reliably move the price. When we survey a job, these are the things we are checking for.

• Number of circuits (ways). A one bed flat might have six circuits; a large Victorian house can have twelve or more. More ways means a bigger board, more protective devices and more testing time.
• Condition of the existing wiring. A new consumer unit must only be connected to circuits that are safe. If testing reveals faults, those need fixing first, and that is extra work.
• Earthing and bonding upgrades. Older London properties often lack main bonding to gas and water pipes, or have undersized earthing conductors. BS 7671 requires these to be brought up to standard before the new unit is energised.
• Surge protection and arc fault detection. Current editions of BS 7671 require surge protection devices (SPDs) in most domestic installations, and arc fault detection devices (AFDDs) are required or recommended in certain situations. These add to the parts cost.
• Tight access. Consumer units in cramped cupboards, under stairs or behind boxing take longer to work on safely.
• Older properties needing remedial work first. Rubber or fabric insulated cable, shared neutrals and borrowed lighting circuits are common in pre war London stock and must be dealt with before a new board goes in.

What a proper job includes

The board itself is only part of the work. A consumer unit replacement done properly always includes testing of every circuit before and after the change, because connecting a new board to faulty circuits just hides the problem behind a shiny front.

You should receive an Electrical Installation Certificate covering the work, with full test results for every circuit. The new unit should be clearly labelled so anyone can identify which device covers which circuit, and the work should be notified to building control, which is a legal requirement for this type of work in England.

If your quote does not explicitly include testing, certification and notification, it is not a quote for the same job. Ask directly, in writing, before you accept.

Warning signs your fuse box needs replacing

Plenty of older boards are still safe. But some tell you clearly that their time is up, and a few of these signs mean you should act quickly rather than putting it off.

• Rewirable fuses (fuse wire you replace by hand) rather than modern circuit breakers.
• No RCD protection, meaning nothing on the board trips fast enough to protect you from electric shock.
• A wooden backboard, cast iron switchgear or visible scorch marks around the unit.
• Buzzing, crackling or a warm smell near the board.
• Breakers that trip repeatedly for no obvious reason, or a board with no spare capacity for new circuits.
• An EICR that has coded the consumer unit C2, meaning it is potentially dangerous.

Why cheap quotes go wrong

The £300 consumer unit swap exists, and we regularly get called to put it right. It usually goes wrong in one of three ways. First, no proper testing, so existing faults are carried over and the new RCDs trip constantly, or worse, a dangerous fault stays live. Second, no bonding upgrade, so the installation still fails the standard it was supposedly brought up to. Third, no certificate and no notification, which becomes your problem when you sell the house and the buyer's solicitor asks for paperwork you do not have.

A low price is only a saving if the job is the same job. Once you add the return visit to fix nuisance tripping, the missing certificate and the bonding that should have been done first, the cheap quote is usually the expensive one.

What to expect on the day

A straightforward replacement takes most of a day. The power will be off for several hours while the old unit comes out, the tails and circuits are connected to the new board, and everything is tested. Plan around no kettle, no wifi and no fridge for that window, and let us know in advance if anyone in the house relies on powered medical equipment.

We start by testing the existing circuits, so if anything is going to complicate the job we know in the first hour, not the last. The old unit comes off the wall, the new one goes up, every circuit is dead tested and then live tested, RCDs are timed, and the board is labelled. You get the certificate once the paperwork is complete, and the building control notification follows.

Getting a straight quote

The honest answer to "how much?" is that nobody can price a consumer unit replacement accurately without knowing the number of circuits, the earthing arrangement and the general condition of the installation. Photographs of your existing board, the meter position and the main earth connection get you a realistic figure quickly.

If your board is old but you are not sure it is dangerous, an EICR is a sensible first step. It tests the whole installation, tells you exactly what needs doing and in what order, and stops you paying for work you do not need. Either way, get the scope in writing, make sure certification is included, and be suspicious of any price that seems too good for London.