Ask three electricians what a fuse board replacement costs in Central London and you will get three different answers, and none of them is being evasive. The reason is simple: the board itself is the smallest part of the job. What you are really paying for is what happens around it — how many circuits feed off it, where it sits, how easy it is to get to, and above all what condition the wiring behind it turns out to be in once the cover comes off. Two flats on the same landing in the same Marylebone block can produce very different jobs, because one was partially rewired in the 1990s and the other was not.
This page explains what actually moves the number, so that when you get a quote you can read it properly and ask the right questions. It does not give a range, because a range invented before anyone has looked at your board is a guess dressed up as information. Our electrical work starts from £80 and the set prices are published on the electrical services page; for a board replacement we look first, then give you a fixed price before anything is switched off.
What a consumer unit replacement actually involves
The old term is a fuse board. The current term is a consumer unit. Whatever you call it, it is the point where the supply from your meter is split into the circuits that run round the property, and where each of those circuits gets its protection. Replacing it is not a swap of a plastic box. It is a controlled disconnection of the whole installation, a re-termination of every circuit into a new board, and then a round of testing on each of those circuits to prove that what you have reconnected is safe to energise.
That testing step is where the surprises live. An electrician cannot sensibly re-energise a circuit that fails its tests. So the job is not "fit board, done" — it is "fit board, test everything, deal with whatever the tests reveal". On a 2015 flat, the tests confirm what everyone expected and the job closes the same day. On a 1930s mansion block flat that has never been fully rewired, the tests can find a lighting circuit with degraded insulation that must be dealt with before it can go back on. That is not the electrician inventing work. It is the board doing the job it exists to do — modern protective devices are far more sensitive than old rewireable fuses, and they surface faults the old board tolerated quietly for years.
The things that genuinely move the price
Rather than a made-up figure, here is what an honest quote is actually weighing up.
- Circuit count. A studio with four circuits and a five-bedroom house with twenty are different jobs. Every circuit has to be identified, re-terminated and individually tested. The board is priced by the number of ways it needs.
- Board position and access. A board at chest height in a hallway cupboard is straightforward. A board above a kitchen wall unit, behind a boiler, at the top of a stairwell, or in a communal meter cupboard three floors down is not. Time on ladders or in cramped cupboards is still time.
- Condition of the existing wiring. The single biggest variable. Sound modern cable re-terminates cleanly. Old cable with brittle insulation at the tails may need remedial work at the board end or, in the worst case, tells you the circuit itself needs replacing.
- What gets exposed once it is open. Missing earthing to the gas and water services, no main protective bonding, a supply arrangement that is not what the paperwork claims, junction boxes buried in inaccessible places. Any of these must be corrected as part of a compliant installation.
- Whether remedial work or a partial rewire becomes necessary. Sometimes the answer to a failed circuit is a repair. Sometimes it is a new circuit. That is a conversation, not a fait accompli — see our guide to rewiring a period property for how that decision gets made.
- Certification. The job is not finished until the paperwork is. Testing time and the certificate are part of the work, not an add-on.
- Occupied or vacant. An empty flat can be worked through in one clean run. An occupied home means staged isolation, working around people, keeping a fridge and a router alive, and often finishing later than a bare property would allow.
Why Central London stock makes this less predictable
In much of the country, an electrician can put a fairly narrow price on a board change because the housing stock is fairly uniform. Prime Central London is not uniform. The flats we work in around W1, W2, NW8 and W9 are frequently conversions of Victorian and Edwardian buildings, or purpose-built mansion block units, and the electrical installation in them is an archaeology of every previous owner's decisions. It is common to open a board in a period conversion and find three eras of cable meeting in one enclosure: something modern from a kitchen refit, something from a 1980s update, and something original enough that its insulation crumbles when you flex it.
Rubber-insulated and lead-sheathed cable still turns up in older Central London properties. So do lighting circuits with no circuit protective conductor at all, which is one reason so many period flats still have plastic light switches — a metal one would have nothing to earth to. None of that is visible from the outside of a board. It is the reason a responsible electrician wants to test before pricing, rather than after.
The access problem in flats and blocks
The physical location of the equipment in a block adds a layer that houses do not have. Your meter and your incoming supply may sit in a communal cupboard on the ground floor, on a landing, or in a basement intake room — and that cupboard may be locked, may be the freeholder's or the managing agent's responsibility, and may need a porter or building manager to open it. If the main isolator has to be pulled to work safely, that can involve the distributor rather than your electrician, on their timescale rather than yours.
Practically, that means a board change in a mansion block often needs a phone call before it needs a van. Many blocks in Maida Vale and St John's Wood also restrict working hours and require works to be booked with the managing agent in advance. None of this is difficult; all of it is time, and time that is not planned for is time that turns into a second visit.
Regulation: what applies and what it means for you
Electrical work in dwellings falls under Building Regulations Part P, and installations are designed and tested to BS 7671. Replacing a consumer unit is notifiable work. In practice that means it must be carried out by someone competent and it must be certified, with the local authority notified through the appropriate route. You should end up holding a certificate for the work. If a quote does not mention certification, that is a question worth asking before you accept it, not after.
If you are a landlord, the board sits inside a wider duty. Rented homes in England require an EICR at least every five years under the Electrical Safety Standards in the Private Rented Sector (England) Regulations 2020, and it is very often the EICR that triggers the board conversation in the first place. Our guide to EICR certificate costs covers that side. An EICR is an inspection; it produces coded observations. A board replacement is one of the possible responses to those codes — not automatically the right one, and worth understanding before you commission it.
Leaseholders have one extra thing to check. Most leases require the freeholder's or managing agent's consent for alterations, and while a like-for-like board replacement inside the demise is usually less contentious than moving it, "usually" is not "always". If the board is being relocated, or if the work touches anything outside your demise, confirm the position with your managing agent before you book. Where a whole block is doing electrical works communally, Section 20 consultation under the Landlord and Tenant Act 1985 can come into play for works over £250 per leaseholder — that is a building matter rather than a flat matter, but it is worth recognising which one you are in.
Reading a quote properly
A board replacement quote should tell you, at minimum, how many ways the new board has, what protective devices are going in it, whether the price includes testing and certification, what happens if a circuit fails its tests, and how long the power will be off. That last one matters more than people expect in an occupied flat. If the quote is a single number with no scope behind it, you have no way of knowing what is included, and no basis for comparing it with anyone else's single number.
Be particularly careful with quotes that are conspicuously cheap. The way to make a board change cheap is to skip the testing, and the testing is the part that keeps you safe. A board fitted without proving the circuits behind it is a new lid on an unknown problem.
When a board change is the wrong answer
Sometimes people arrive at a board replacement because something keeps tripping and a board change sounds like a fix. Usually it is not. A board that trips is often a board correctly reporting a fault on a circuit or in an appliance, and replacing it will not remove the fault. If that is where you are, start with our guide to no power and a tripping fuse box, or with proper electrical fault finding. Diagnosing first is cheaper than replacing first, and far more likely to solve the problem you actually have. Equally, if the installation behind the board is genuinely at the end of its life, a new board on old wiring is money spent at the wrong end of the job.
The technical background to what a modern board must do, and why older ones fall short, is covered in our guide to consumer unit upgrades and regulations.
How we price it
We publish set prices rather than improvising them on a doorstep. Electrical work starts from £80, and the published rates are set out there. For a consumer unit replacement, the sequence is: look at the board and the installation, test enough to understand what is behind it, then give you a fixed price in writing before any work starts. If the testing reveals something that changes the scope — degraded cable, missing bonding, a circuit that will not pass — you get told before it becomes a cost, with the options laid out and a price against each.
What we will not do is quote a number over the phone for a board nobody has seen, then revise it upwards on the day. That is the practice that has made people distrust electrical quotes, and it is entirely avoidable. If you would like the board looked at properly, send us the details or WhatsApp a photo of the board with its cover on and of the meter cupboard, and we will tell you what we can see and what we need to check. If the property is a rental or a managed block, ongoing electrical items across a portfolio usually sit better under planned maintenance than as a series of emergencies.