Why boards get replaced
A consumer unit is the thing everything else depends on. When it is old, it is usually the cheapest single change that makes a real difference to safety.
The usual reasons
- A rewireable fuse board, or one with no RCD protection at all
- An unsatisfactory EICR listing the board itself as a C2
- Circuits added over the years until the board is full and unbalanced
- A plastic board in a location where a metal enclosure is now required
- Adding something substantial — an EV charger, a kitchen, an outbuilding supply
A modern board does not just protect the wiring. RCD and RCBO protection is what protects a person who drills through a cable or cuts a mower lead.
What a modern board gives you
Current boards are built to a different standard from what most houses still have.
- Metal enclosure — required in domestic premises, and it contains a fault rather than feeding it
- RCBOs on individual circuits — a fault takes out one circuit rather than half the house, which matters more than people expect at eleven o'clock at night
- Surge protection — increasingly worth having given what is now plugged into a house
- Spare ways — so the next addition doesn't mean starting again
- A legible circuit schedule — labelled properly, so anyone can see what does what
What a consumer unit replacement costs
There isn't a single price that applies to every property, because the cost depends on the installation rather than the address. As a guide:
What moves the figure:
- The number of circuits
- Where the existing board is located and how accessible it is
- The condition and arrangement of the existing installation
- The type and size of consumer unit required
- Whether additional work is needed to bring the installation up to standard
- The type of protection — a split-load board, or individual RCBO protection on every circuit
Individual RCBOs cost more than a standard split-load arrangement, but they mean a fault takes out one circuit rather than half the house. We'll explain the difference and let you decide.
We use consumer units from reputable manufacturers, with quality accessories and components throughout. It is not a place to save twenty pounds.
Why we inspect before changing a board
We will always carry out a periodic inspection or EICR before replacing a consumer unit, and it is worth explaining why, because not everyone does.
Changing the board does not make the rest of the installation safe or compliant. The new board simply protects whatever is already there — and if there are faults on the existing circuits, a modern RCD will find them the moment it is energised.
Without inspecting and testing first, a board change becomes an open-ended cost. Problems get discovered halfway through, with the old board already out and the power off, and suddenly the price is a moving target.
Inspecting first means we can tell you exactly what work is required and what it will cost before the replacement goes ahead. You get a clear picture of the total figure, and unexpected charges are avoided wherever possible.
It is a little more up front and considerably less painful than the alternative.
What the day looks like
The power goes off for a good part of it, so plan around that. Freezers are fine for a few hours; home working is not.
- The existing installation is tested first. There is no sense fitting a new board to circuits with faults on them — the new RCDs will simply trip and reveal problems that were always there.
- The old board comes out and the new one goes in, with the circuits transferred and identified.
- Earthing and main bonding are checked and upgraded if they don't meet current requirements. This is very often needed on older houses and is worth knowing about in advance.
- Everything is tested circuit by circuit, energised, and the schedule labelled.
- Certificate issued and the work notified to building control.
Occasionally the pre-test finds a genuine fault on an existing circuit — usually damaged cable or moisture in an outside light. We tell you before we go further rather than discovering it once the board is out.
Common questions
How much does a consumer unit replacement cost?
There's no single price, because it depends on the installation. As a guide, an average 10-way split-load board is around £395 including materials and installation. Individual RCBO protection on every circuit costs more. We're not VAT registered, so there's nothing to add to the quote.
Do I need an inspection before a board change?
We always carry one out first. Changing the board doesn't make the rest of the installation safe, and a modern RCD will find existing faults the moment it's energised. Inspecting first means you get a firm total cost rather than an open-ended one.
How long does it take?
Most of a day for a straightforward replacement. If the earthing and bonding need upgrading too, or there are faults on existing circuits, it can run into a second day.
How long will the power be off?
Several hours. We'll give you a realistic window when we book so you can plan around it.
Can you quote without visiting?
Usually. Send a photo of the existing board with the cover off if it's safe to do so, plus a photo of the meter position, and we can normally give you a firm price.
Why did my new board start tripping?
Because it's now detecting faults the old one couldn't. That's the point of it. We test before fitting precisely so this comes up beforehand rather than afterwards.
Do I need surge protection?
It isn't compulsory in every case, but given what's plugged into a modern house it's usually worth the modest extra cost. We'll tell you what it adds.
Is the work notified to building control?
Yes. Consumer unit replacement is notifiable under Part P and we handle it as part of the job.
